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Full text of "The Peanut, the unpredictable legume; a symposium"

New York 
State College of Agriculture 
At Cornell University 
Ithaca, N..Y. \, , 



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SB 351.P3P35"""'™""'"-"'™^^ 
^'iSmilliiiiiiim* unpredictable legume; i 




3 1924 002 811 366 




PRINTEDINU.S.A. 




Cornell University 
Library 



The original of tiiis book is in 
tine Cornell University Library. 

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the United States on the use of the text. 



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THE PEANUT— 
THE UNPREDICTABLE LEGUME 



THE PEANUT 

THE UNPREDICTABLE LEGUME 



A SYMPOSIUM 



Prepared by 



FRANK SELMAN ARANT 
ROGER W. BLEDSOE 
W. E. COLWELL 
KENNETH H. GARREN 
WALTON C. GREGORY 
HENRY C. HARRIS 

E. T. YORK, JR. 



B. B. HIGGINS 

BEN W. SMITH 

D. G. STURKIE 

J. T. WILLIAMSON 

COYT WILSON 

JOHN A. YARBROUGH 



WW Wl SilUE; 



Sponsored by 

THE PLANT FOOD RESEARCH COMMITTEE OF 
THE NATIONAL FERTILIZER ASSOCIATION 



Published by 

THE NATIONAL FERTILIZER ASSOCIATION 

WASHINGTON, D. C. 



copyright 1951 
The National Fertilizer Association 

All rights reserved, including the 

right to reproduce this book, or portions thereol 

in any form. 

S3 

?3 
P3^ 



PRINTED IN THE UNITED STATES OF AMERICA 

First Printing 1951 



178301 



Typography, Layout and Printing by 

The William Byrd Press, Inc. 
Richmond, Va. 



The National Fertiliser Association 

and the chapter authors 

take pleasure in dedicating this book 

to the advancement of American Agriculture 



PREFA C E 

The Peanut — The Unpredictable Legume has brought together 
between two covers authoritative information on this crop. From a mass 
of data, much of which is contradictory, inconsistent and erratic, here is 
presented a consoHdation and interpretation of present-day ideas which 
forms a sound foundation for further needed research on the economic 
production of peanuts — the most pecuhar of all major farm crops. This 
volume is a valuable contribution to the understanding of the peanut 
plant and its economic production. It should not be construed as an end 
point to the problems in agronomy, plant nutrition, plant physiology, 
plant pathology, biochemistry, agricultural engineering and entomology. 
Many of such problems, however, are clarified by the material presented. 

Generous credit is due the chapter authors upon whom the burden of 
preparing the subject matter fell. Years of patient work in consolidating 
and interpreting the results in each field of investigation are represented 
by THE PEANUT— THE UNPREDICTABLE LEGUME. The con- 
tributions of the chapter authors have been unselfishly made in the in- 
terest of the advancement of agricultural science. They deserve the grati- 
tude of all producers, processors and consumers of peanuts. 

The development of this volume began in 1937 when the great prob- 
lems of varying results involving fertilizer field trials engaged the atten- 
tion of the Plant Food Research Committee of The National Fertilizer 
Association. The need for more research was presented to and approved 
by the Southeastern Agronomy Research Committee of the Southeastern 
Experiment Stations, January 31, 1939. Then followed a series of confer- 
ences of research workers. These scientists contributed data and obser- 
vations which stimulated new research and clarified previous findings. 
Annual conferences were held from 1939 to 1944, inclusive, and, after a 
year's omission, were resumed in 1946 and continued through 1948. 

Personalities involved in the many investigations and contributing to 
the understanding of peanut production problems at the various con- 
ferences included many distinguished authorities. 

Chairmen of the conferences during the various years were: W. E. 
Stokes, Florida Agricultural Experiment Station, N. J. Volk, Alabama 
Agricultural Experiment Station, and R. W. Cummings, North Carolina 



viii THE PEANUT— THE UNPREDICTABLE LEGUME 

Agricultural Experiment Station, all of whom gave generously of their 
time. 

Financial support for the annual conferences and for the publication 
of this book was contributed by The National Fertilizer Association. 

It would be a great injustice not to recognize the efficient work of 
H. R. Smalley, R. H. Lush and M. H. McVickar, all of The National 
Fertilizer Association, who served as secretaries of the various confer- 
ences. 

Members of the Plant Food Research Committee of The National 
Fertilizer Association who served on the Peanut Research Committee at 
various times include : T. F. Bridgers, C. J. Cahill, Leroy Donald, Myron 
S. Hazen, G. N. Hoflfer, Frank L. Holland, Wallace Macfarlane, H. B. 
Mann, R. D. Martenet, F. W. Parker, J. R. Taylor and the undersigned 
Chairman. 

Respectfully submitted, 

David D. Long, Chairman 
Subcommittee Peanut Fertilization 
Plant Food Research Committee 
The National Fertilizer Association 



CONTENTS 

I'ACE 

Preface vii 

CHAPTER I 

Economic Importance of Peanuts 3 

B. B. Hi^gins 

CHAPTER H 
Origin and Early History of the Peanut ...".. 18 
B. B. Higgins 

CHAPTER HI 

Morphology, Genetics and Breeding 28 

Walton C. Gregory, Ben W. Smith, John A. Yarbrough 



CHAPTER IV ^ 

Physiology and Mineral Nutrition '. 89 

Henry C. Harris, Roger W. Bledsoe \ 

CHAPTER V 
Soil Properties, Fertilization and Maintenance of Soil 

Fertility 122 

E. T. York, Jr., W. E. Colwell 

CHAPTER VI 

Cultural Practices 173 

D. G. Sturkie, J. T. Williamson 

CHAPTER VII 

Insect Pests 210 

Frank Selman Arant 

CHAPTER VIII 

Peanut Diseases 262 

/Kenneth H. Garten, Coyt Wilson 



THE PEANUT— 
THE UNPREDICTABLE LEGUME 



/ CHAPTER 1 

ECONOMIC IMPORTANCE 
OF PEANUTS 

By 
B. B. HIGGINS' 

The peanut is generally recognized as one of the important crop 
plants of the world. This recognition has arrived very slowly. Although 
the plant has been known to Europeans since the sixteenth century, it 
was only approximately 100 years ago that the oil mills of Marseilles, 
France, began importing and crushing peanuts grown in North Africa. 
This may be considered the beginning of large-scale industrial use of the 
crop, though an oil mill was established at Valencia, Spain, SO years 
earlier (7). The desirable qualities of the peanut oil brought early success 
to the enterprise, and mills for crushing peanuts were quickly established 
in other European countries. Since then, the commerce in peanuts has 
expanded slowly to its present proportions. In 1947 the commercial crop 
of the world amounted to 10,579,000 tons. 

The relative importance of the producing areas of the world is shown 
in table 1. While figures given for many countries are admittedly only 
estimates, they do indicate the relative importance of various world areas 
insofar as the commercial production of peanuts is concerned. They in- 
dicate that the peanut is now an important crop in the warmer areas of all 
six continents of the world. The wofld trade depends largely on the 
European demand for oil. India, China, Burma, Sumatra, Java, and the 
French African colonies have long been the principal exporters of peanuts. 
At present, the supply is inadequate to meet the demand. World War II 
so upset and confused agricultural production in Europe that there is an 
enormous shortage of edible fats and oils. Increased production of peanut 
oil appears to offer the most feasible possibility for early and permanent 

> B. B. Higgins is botanist, Georgia Agricultural Experiment Station. 

3 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 1. — Peanut Acreage and Production in Specified Areas and Countries." 
Sources of data: Foreign Crops and Markets, U. S. Dept. Agri. 55 (22): 371-373; 

57 (22): 427-430. 



Continent and 
Countries 



Average 1935-39 



Acreage Production 



Average 1943-47 



A creage Production 



Average 
1943-47 



Acre 
Yield 



tons 



tons 



pounds 



North America 

Mexico 

United States. . . . 

Cuba 

Dominican Republic 
Total"" 

Europe 

Bulgaria 

Italy 

Spain 

Total'' 

Russia 

(Europe & Asia) . . . 

Asia 

Burma 

China proper 

Manchuria 

French India 

French Indo China 

India 

Japan proper 

Formosa 

Kwantung 

Netherlands Indies 

Philippine Islands . 
Totalb 

South America 

Argentina 

Brazil 

Paraguay 

Uruguay 

Totalb 

Africa 

Anglo-Egyptian' 

Sudan 

Belgian Congo .... 

Tanganyika 

Uganda 

Gambia 

Egypt 

Fr. Equatorial 

Africa and 

Cameroun 



33,000 
1,659,000 



1,800,000 



5,000 

2,000 

24,000 

35,000 



29,000 



784,000 
3,639,000 

7,000 

42,000 

7,535,000 

19,000 

77,000 

101,000 

572,000 

18,000 

13,200,000 



207,000 

29,000 

5,000 

400,000 



43,000 
245,000 
277,000 
156,000 

23,000 



388,000 



12,200 

614,700 

8,400 

3,800 

640,000 



2,200 

1,600 

23,300 

28,000 



192,200 

2,913,400 

121,600 

5,600 

16,000 

3,295,700 

14,600 

57,700 

91,100 

289,100 

4,700 

7,040,000 



87,300 

14,800 

19,400 

1,200 

129,000 



8,100 
65,100 
23,400" 

2,200= 
58,100 
17,200 



58,800 



98,333 

3,409,000 

95,800 

35,400 

3,494,000 



3,400 

7,600 

16,333 

33,000 



636,250 
3,444,000 

7,000 

107,000 

10,123,800 



430,400 
15,238,000 



330,800 
87,000 
21,500 
16,400 

520,000 



55,000 
540,000 

333,333 

25,800 



43,750 
1,052,580 

27,200 

8,180 

1,136,200 



940 

5,320 

11,433 

20,000 



127,050 
2,614,300 

5,633 

27,000 

4,005,258 

19,800 



190,440 
7,246,600 



154,120 

34,133 

13,250 

4,700 

208,000 



500 

6,620' 

9,550" 

84,900 

19,760 



890 
618 
568 
462 
650 



553 
1,400 
1,400 
1,212 



399 
1,518 

1,609 
505 
791 



885 
951 



932 
785 
1,233 
573 
800 



418 



1,532 



ECONOMIC IMPORTANCE OF PEANUTS 
Table 1 — Continued 



Continent and 
Countries 


Average 1935-39 


Average 1943-47 


Average 
1943-47 


Acreage 


Production 


Acreage 


Production 


Acre 
Yield 




acres 


tons 


acres 


tons 


pounds 


Fr. West Africa 

Madagascar 

Mozambique 

Nigeria and 

Cameroons 

Angola 


2,955,000 
14,000 

18,000 

56,000 
6,120,000 

14,000 
15,000 

21,600,000 


875,900 

6,600 

42,900° 

354,700° 

6,200 

28,000° 

12,000 
1,673,000 

6,100 
6,500 

9,531,000 


26,400 
2,500,000 

95,000 
6,000,000 

23,800 
27,200 

25,380,000 


527,340 

7,980 

19,525 

538,400° 

7,267 

33,733 

22,600 
1,461,600 

23,900 
13,800 

10,090,600 


605 
431 


Portuguese Guinea. 
Union of South 
Africa 


476 


Total'' 


487 


Oceana 

Australia 


1,168 


Totalb 


1,015 


World Total 


795 



» Harvested crop statistics not complete for all years of periods covered, 
■> Continental totals include estimates for other minor producing countries. 
" Exports only. 

relief. A large government-sponsored project for increased peanut pro- 
duction in the Belgian Congo is already in operation ; another, sponsored 
by the British Government, has for its objective the mechanized produc- 
tion of peanuts on 3 million acres in Tanganyika and Northern Rhodesia ; 
and production in French West Africa and Nigeria is being vastly 
expanded. 

Previous to development of the peanut oil industry, the world trade 
in peanuts was unimportant. However, in every country where grown, 
they were considered an important item of food and considerable local 
trade sprang up. The peanuts were most commonly roasted in the shell 
and sold for immediate consumption. They were also used for making 
candy and other confections. While a peanut paste similar to peanut 
butter was apparently made and used by the South American Indians, 
utilization of peanuts in this type of product has not reached commercial 
importance except in the United States. In Spain and in some Spanish- 
American countries, peanuts are ground, mixed with cocoa or with 
honey and utilized for food ; but exact data as to the extent of this utili- 
zation are not available. 



6 THE PEANUT— THE UNPREDICTABLE LEGUME 

DEVELOPMENT OF THE PEANUT INDUSTRY 
IN THE UNITED STATES 

"Groundnuts" are mentioned ( 19, 20) in some of our earliest Colonial 
^cords, but this name was used for other plants as well as for peanuts, 
■''and we are often not sure what plant was indicated. Whether or not 
peanuts were grown within the present limits of the United States by the 
Indians of pre-Columbian times is still questionable, but we do have 
authentic records of peanut culture during Colonial days. The following 
quotation from a report by Sir William Watson (27) to the Royal Society 
and published in the Philosophical Transactions for October 1769 is of 
special interest: 

"It is with this view, that I lay before you some pods of a vegetable 
and the oil pressed from them. They were sent from Edenton, in North 
CaroHna, by George Brownrigg, whose brother. Dr. Brownrigg, is a 
worthy member of our Society; and are the produce of a plant well 
known and much cultivated in the Southern colonies and in our American 
sugar islands, where they are called groundnuts, or ground pease. . . . 
Mr. Brownrigg, from whom as I before mentioned, I received the oil, 
considers the expressing oil from the ground pease, as a discovery of his 
own: It may, perhaps, at this time, be very little practiced either in 
North Carolina, the place of his residence, or elsewhere. But certain it 
is that this oil was expressed above fourscore years ago; as Sir Hans 
Sloane mentions it, in the first volume of his History of Jamaica ; and 
says that this oil is as good as that of almonds. . . . After the oil has 
been expressed from the ground pease, they are yet excellent food for 
swine." 

Thomas Jefferson (6) mentioned peanuts as being commonly 
grown in Virginia, but implied that the crop was of little importance 
(Commercially. Before the Civil War, they were grown commercially 
at least for local consumption throughout the South and even in Cali- 
fornia. Ramsey (23) in his history of South Carolina, 1809, mentioned 
among vegetables, groundnuts used as a food, as a substitute for cocoa, 
and as a source of oil for domestic use. In discussing Edisto-Island, he 
again mentioned groundnuts, saying, "They are planted in small patches 
chiefly by negroes for market. They produce 80 bushels per acre. They 
are commonly sold for five shillings sterling per bushel. . . . price in 
1768 was eight pence sterling per bushel." The fact that they were being 
grown commercially in South Carolina is shown also from records of 
exports from the port of Charleston. We find a shipment of 51 casks of 



ECONOMIC IMPORTANCE OF PEANUTS 7 

groundnuts recorded (8) for the year November 1786 to November 
1787. Williams (28), in discussing the agriculture of the Territory of 
Florida (1830) says: "The peanut produces a large crop and is a useful 
article in the dessert." Burke (9), in describing life on a slave-operated 
plantation near Savannah, Georgia, during the first half of the nineteenth 
century, says: "Great quantities of peanuts are raised there, not only as 
an article of export, but to fatten swine upon. They are planted in the 
same manner as potatoes and when they have come to maturity the 
swine are turned in upon them to dig their own food. It is not usual for 
planters to feed their swine in any other way. . . ." 

Several others writing from Georgia (4, 23), Alabama (13), Missis- 
sippi (22), Louisiana (17) and California (5) at about this date spoke 
of peanuts as a valuable crop, especially for hog feed. In 1851, W. B. 
Easby (15) of Vernon, Tennessee, wrote: "The goober pea is extensively 
raised here, and so far has proved the most profitable crop that can be 
raised. The first ever raised for market was sold in Nashville in the fall of 
1845. Since that time there has been upwards of 20,000 to 25,000 bushels 
raised within 10 to 15 miles of this place each year, and sell for 65 cents 
to one dollar per 22 pounds. The vine is equal to clover hay for stock, if 
well saved." 

During and after the Civil War commercial production increased 
rapidly. Exact statistical records for the period are not available, but 
in the Annual Report of the U. S. Department of Agriculture for 1868 4., 
is found a 4-page discussion of the crop. It is stated that the Virginia 
crop for that year was estimated at 300,000 bushels, selling at $2.75 a 
bushel (22 pounds). Two varieties are mentioned: Virginia and the 
Carolina or African! 

At this time most of the commercial crop was roasted in the shell 
and sold freshly roasted by street vendors. The work of harvesting, pick- 
ing and preparing for market was all done by hand or with crude home- 
made equipment. Lack of commercial shellers undoubtedly retarded 
utilization of peanuts. Lack of uniformity and poor quality discouraged 
trade in peanuts even for roasting. Some farmers built crude equipment 
for scrubbing and shaking dirt from the peanuts and blowing out trash 
and "pops," and hand-picked the discolored nuts ; but this practice for 
improving the uniformity and quality of the product was not general. 
In 1870, P. D. Gwaltney (7) began buying peanuts from growers about 
Smithfield, Virginia, cleaning them as best he could with such crude 
equipment as available, and reselling. Ten years later, he, in partnership 
with A. Bunkley, built what is said to have been the first factory for 



8 



THE PEANUT— THE UNPREDICTABLE LEGUME 



cleaning, grading, and polishing peanuts to be roasted in the shell. Ap- 
parently, however, another factory was built in New York City about the 
same date (21), probably for cleaning imported stock. 







K 



Figure 1. — Typical modern peanut processing plant. 



More important for development of the peanut industry was the in- 
vention and manufacture of machinery for planting, cultivating and 
harvesting the plant, picking the nuts from the plants, and for shelling 
and cleaning the seed. Without these labor-saving machines, peanut 
production would undoubtedly have declined with the gradual increase 
in cost of human labor. In 1872, H. E. Colton ( 12) writing about pea- 
nuts, said that under stress of producing peanuts for oil during the Civil 
War, a mechanic, Thomas L. Colville of Wilmington, North Carolina, 
built machines for threshing the nuts from the vines and winnowing them 
and also built machines for removing the shells. Neither machine was 
patented and many variations and improvements were tried before a 
really satisfactory picker was built about the beginning of the present 
century. Development of a successful planter, of the scraper plow, the 
weeder, and the peanut wing for cutting the roots in harvesting, are 
among the important inventions that materially reduced the labor of 
producing peanuts and led to vast expansion of the peanut industry 
during the present century. The mechanical sheller has been an espe- 
cially important factor in increasing the use of peanuts and peanut pro- 
ducts such as peanut oil, roasted and salted nuts, peanut butter, peanut 
candy, and other confections. 



ECONOMIC IMPORTANCE OF PEANUTS 9 

Apparently pre-Columbian Indians of America ( 14) and the African 
natives (11) made and used both peanut oil and a peanut paste com- 
parable with our peanut butter long before the white man used either 
product. Apparently, peanut butter was first made commercially about 
1890 by a physician (25) in St. Louis, Missouri, who prescribed it for 
some of his patients as a nutritious, easily digested, high-protein food, low 
in carbohydrates. The idea spread rapidly. Winton (29), in 1899, 
published analyses of two brands; and in 1914, Utt (26) analyzed and 
examined for adulterants 23 brands bought on the markets of Kansas 
City. At present, more than half the peanuts shelled for the edible trade 
go into the production of peanut butter. 

The increased need for oil for various uses in time of war has caused 
great expansion of peanut production during each such, period since 
1860, and other uses have usually absorbed the increase in each sub- 
sequent period. Several writers agree that rapid expansion occurred 
between 1860 and 1870. Again referring to the article by Colton (12), 
published in 1872, we read : "Instead of 1,000 there are fully 550,000 
bushels sold annually in the city of New York alone. Previous to 1860, 
the total production of the United States did not amount to more than 
150,000 bushels, and of this total fully five-sixths were from North Caro- 
lina. Now, North Carolina produces 125,000 bushels ; Virginia, 300,000 
bushels ; Tennessee, 50,000 bushels ; Georgia and South Carolina, each, 
25,000 bushels ; while from Africa come about 100,000 bushels a year." 
We may feel inclined to doubt Colton's data, but his estimates as to the 
size and the distribution of the industry cover a period for which we 
have no authentic records. It seems probable that the estimates were 
based on only that portion of the crop which entered interstate commerce, 
since statistics on crop acreage in Georgia, furnished by the Comptroller 
General to the Georgia Agricultural Society (6), gave for the peanut crop 
16,619 acres in 1873 and 21,162 acres in 1874, several times the acreage 
necessary to produce 25,000 bushels. 

, Acreage and production of peanuts are recorded in the Eleventh 
Census Report for the year 1889, and are included in all subsequent 
enumerations. The U. S. Department of Agriculture, through its system 
of crop estimates, has kept fairly accurate annual records of total acreage 
planted, acreage harvested, and the production by States. During the 
period of acreage limitation, from 1934 to 1942, more exact data were 
obtained as to the harvested acreage and production. 

In order to facilitate marketing the crop, three producing areas have 
been designated : The Virginia-Carolina area, including Virginia, North 



10 THE PEANUT— THE UNPREt)iCTABLfi LEGuME 

Carolina, and Tennessee; the Southeastern area, including South Caro- 
lina, Georgia, Florida, Alabama and Mississippi ; and the Southwestern 
area, including Louisiana, Arkansas, Texas, Oklahoma and New Mexico 
(figure 2). The division into these three areas is based somewhat upon 
the type of peanut grown. The Virginia-Carolina area produces the 
Virginia-type peanut almost exclusively, while it is, at present, of minor 
importance in the other two areas. In the Southeastern area, the small 
Spanish type constitutes the major portion of the commercial crop. A 
small seeded runner of the African type is grown under several varietal 
names and enters the trade as "Southeastern Runner." The Virginia- 
type peanut is grown in Bulloch County, Georgia, and to a less extent in 
a few other localities. In the Southwestern area, the commercial crop is 
almost exclu^vely of the Spanish type, though a small acreage of Tennes- 
see Red is grown in New Mexico. See table 2 for varietal distribution. 

Data in table 3 show something of the development of peanut pro- 
duction for the country as a whole and for the seven States that account 
for about 90 percent of the total tonnage of the country. It is of interest 
to note the slight increase of acreage in Virginia and North Carolina 
during the World War II period in contrast with the enormous expan- 
sion in certain States of the Southeastern and Southwestern areas. This is 
probably due to the restricted adaptability of the Virginia type in con- 
trast with the more widely adapted Spanish ; and also to concentration of 
peanut acreage. Over the past 20 years the planted acreage has surpassed 
that harvested by about a million acres: Georgia, 400,000 to 600,000 
acres; Florida, 150,000 to 300,000; and Alabama, about the same as 
Florida, with scattered acreage in most other States of the South, grown 
specifically for hog grazing. 

According to the 1890 Census Report, some acreage of peanuts was 
grown in 34 States the previous year, and some acreage was reported 
from practically every county of the Cotton Belt. In the 1945 Census of 
Agriculture, some acreage was reported in 32 States. The distribution of 
this acreage, shown in figure 2, indicates all States in which 1,000 or 
more acres were reported. In most of the 32 States plantings consisted of 
small plots for home use only. 

One can only guess as to how the peanut industry would have de- 
veloped under the system of free competition prevalent prior to 1933. At 
that time the policy of government guarantee of a base price, in consid- 
eration of acreage limitation by growers of major farm crops, caused a 
slight decrease in acreage ; but this decrease had been overcome by 1939. 
During the war years the abnormal demand for food by our own armed 



ECONOMIC IMPORTANCE OF PEANUTS 



11 




12 



THE PEANUT— THE UNPREDICTABLE LEGUME 



forces and those of our allies was such that government controls became 
inoperative between 1943 and 1947. This demand at high prices caused 
enormous expansion in most producing areas. Lack of machinery, espe- 
cially pickers, for handling the crop and lack of marketing facilities pre- 
vented expansion outside the old producing areas. With these limitations 
removed, production within the United States could easily be doubled 
again. 

At present prices, No. 1 grade peanuts cannot profitably be crushed 
for oil; and comparatively few peanuts of this grade are used for 
such purpose. Those crushed are, for the most part, "off -grade" lots and 
screenings, shrivels, splits and pick-outs from shelled No. 1 grade. As 
an example, the proportional distribution (29) of the 1947 crop to vari- 
ous usages is shown in figure 3. 




Figure 3. — Proportional distribution of 1947 peanut crop to various usages. 



Of the one and one-half billion pounds listed as cleaned and shelled, 
80 million pounds were merely cleaned for roasting in the shell. These 
were mostly Virginia-type, but included a few of other types. The distri- 
bution by varieties in the shelled edible trade follows : 



ECONOMIC IMPORTANCE OF PEANUTS 13 

Table 2. — Distribution by Varieties in the Shelled Edible Trade 





Pounds 


Percent 




174,131,000 
193,904,000 
401,224,000 


22.6 




25.2 




52.2 






Total 


769,259,000 


100.0 







Of this total, 189,683,000 pounds were exported, leaving 579,576,000 pounds for domestic use. 



Table 3. — ^Acreage and Production in the United States and in Each of the 
Principal Producing States for Specified Years Between 1889 and 1947. 









Acreage Harvested {000 acres) 






Year 


















U.S. 


Va. 


N.C. 


Ga. 


Fla. 


Ala. 


Texas 


Okla. 


1889" 


204 


59 


18 


52 


26 


24 


2 


b 


1899" 


517 


117 


96 


100 


69 


79 


11 


2 


1909 


537 


145 


180 


45 


15 


60 


48 


1 


1919 


919 


133 


126 


201 


55 


300 


90 


8 


1929 


1,269 


153 


220 


375 


51 


213 


142 


50 


1939 


1,787 


148 


245 


670 


85 


300 


322 


53 


1940 


2,052 


158 


257 


730 


90 


310 


335 


82 


1941 


1,900 


134 


229 


650 


85 


315 


340 


72 


1942 


3,362 


148 


270 


1,060 


115 


516 


870 


218 


1943 


3,492 


150 


300 


1,127 


110 


574 


850 


200 


1944 


3,068 


154 


295 


1,050 


100 


520 


680 


178 


1945 


3,160 


159 


320 


1,070 


100 


487 


750 


185 


1946 


•3,142 


150 


295 


1,070 


95 


472 


767 


221 


1947 


3,389 


162 


292 


1,092 


105 


452 


877 


325 








Productii 


m, Harves 


ted Nuts ( 


000 tons) 






Year 


















U.S. 


Va. 


N.C. 


Ga. 


Fla. 


Ala. 


Texas 


Okla. 


1889" 


43.1 


12.9 


5.1 


8.7 


5.0 


3.9 


0.6 


— . 


1899" 


143.6 


40.8 


41.5 


20.1 


13.6 


14.3 


2.6 


0.7 


1909 


177.0 


49.3 


60.8 


15.8 


4.9 


19.5 


13.2 


0.4 


1919 


344.1 


70.4 


70.8 


57.8 


18.6 


82.5 


25.9 


2.8 


1929 


449.1 


78.8 


112.2 


121.9 


16.0 


58.6 


29.8 


12.5 


1939 


606.1 


89.5 


195.8 


184.3 


18.7 


71.3 


66.8 


2.0 


1940 


883.3 


107.8 


183.8 


301.1 


34.2 


113.9 


97.2 


22.6 


1941 


737.6 


84.8 


137.4 


234.8 


28.9 


126.0 


79.9 


18.9 


1942 


1,096.4 


85.1 


169.4 


333.9 


32.8 


167.7 


208.8 


60.0 


1943 


1,088.3 


85.5 


153.8 


394.5 


37.4 


208.1 


140.3 


26.0 


1944 


1,040.4 


90.9 


177.0 


304,4 


31.3 


166.4 


153.0 


42.3 


1945 


1,021.1 


74.7 


152.0 


361.1 


33.0 


170.5 


161.3 


43.9 


1946 


1,019.2 


95.6 


136.4 


358.5 


27.8 


129.8 


197.8 


58.6 


1947 


1,094.0 


99.6 


171.6 


390.4 


32.8 


146.9 


186.4 


75.6 



« Total acreage and production for all areas 
•> Only 17 acres reported 



14 



THE PEANUT— THE UNPREDICTABLE LEGUME 



The per-capita consumption of peanuts has just about doubled during 
the past 20 years, and now amounts to more than 10 pounds per person. 
Most of this increase has occurred since 1939 and is doubtless due in 
some measure to extensive use by the armed forces during the war period, 
though civilian use increased during the same period because of scarcity 
of meat. However, during this same period an intensive advertising cam- 
paign was carried on, stressing the food value of peanuts. This campaign 
doubtless had considerable influence. An example of the information 
used in this campaign is shown in table 4, where the nutritive value of 

Table 4. — Nutritive Value of One Pound of Selected Foods as Purchased. 





Unit 


Peanut 
butter 


Roasted 

in 

shell 


Beans 
common 

or- 
kidney" 


Beans 
lima"- 


Beef 


Pork 


Item 


Rib 
roast 
rolled 


Round 
steak 


Fresh 
ham 


Refuse 

Food 

energy... 

Protein. . . . 

Fat 

Carbo- 
hydrates . 

Calcium . . . 

Phosphorus 

Iron 

Vitamin A 
value.. . . 

Thiamin . . . 

Riboflavin 

Niacin 

Ascorbic 
Acid.... 


Percent 

Calories 
Grams 
Grams 

Grams 
Milligrams 
Milligrams 
Milligrams 

I.U. 
Milligrams 
Milligrams 
Milligrams 

Milligrams 




2,808 
118.5 
217.0 

95.3 
336 

1,784 
8.6 


.89 

.72 
73.5 




28 

1,961 

88.0 

144.5 

77.2 

242 

1,285 

6.2 



.96 

.52 

53.0 






1,588 

99.9 

6.8 

281.9 

672 

2,102 

46.8 



2.71 

1.07 

9.6 

8 




1,548 

94.0 

5,9 

279.7 

301 

1,730 

34.0 



2.71 

1.07 

9.6 

8 




1,252 

79.0 

104 



45 

854 

11.8 



.49 

1.07 

21.3 




11 

789 

78.0 

53 



44 

840 

11.7 



.48 

.62 

21.0 




14 

1,326 

59.3 

121 



35 

640 

9.0 



3.75 

.73 

16.0 





* Dry seed. 



peanuts is compared with that of four other common foods (8). Con- 
tinued publication of such information can be expected to have a decided 
influence upon the demand for peanuts and encourages the hope that the 
per-capita consumption of peanuts and peanut products may continue to 
increase rather than recede to the former level. 

Much money and efifort have been expended upon development of 
new ways of introducing peanuts into the diet, utilizing the whole peanut 
or the defatted peanut flour ; but none of these new items has yet become 
important commercially. The important channels for disappearance of 
the edible peanut stocks are shown in figure 4. 



ECONOMIC IMPORTANCE OF PEANUTS 



15 




Figure 4. — Important uses of edible peanut stocks. 

Peanut butter now accounts for disappearance of more than 50 percent 
of our edible stock. Of the 1947 crop, nearly 325 million pounds were 
utilized in peanut butter. This was 56 percent of the shelled edible stock 
retained for domestic use. At present considerable research is being di- 
rected toward improving the quality of peanut butter, and there are indi- 
cations that consumption will continue to increase. 



SELECTED REFERENCES 

(1) Anon. 

1947. WORLD PEANUT PRODUCTION EXCEEDS PREWAR OUTPUT. Foreign Crops 

and Markets, (mimeo.) 55 (22):371-373. U.S. Dept. Agr. 

(2) 

1948. PEANUT STOCKS AND PROCESSING REPORT. U.S. Dcpt. Agr. Weekly 

Peanut Report, (mimeo.) 30 (Sl):3-4. 

(3) 



(4) 
(5) 



1789. GENERAL EXPORTS FROM THE PORT OF CHARLESTON, S. C, FROM NOVEM- 
BER 1786 TO NOVEMBER 1787. The American Museum or Repository. 
5:253. Philadelphia. 



1848. GROUND PEAS. Southern Cultivator 6:40. 



1859. CULTIVATION OF THE PEANUT. Southern Cultivator 17 (3):79. 



16 THE PEANUT— THE UNPREDICTABLE LEGUME 

(6) Anon. 

1874. AGRICULTURAL STATISTICS. Ga. State Agr. Soc, Proc. 46:64. August. 

(7) 

1904. PEANUTS FROM VIRGINIA FOR UNCLE SAM AND THE WORLD. 8 p. booklet 

published by Gwaltney-Bunkley Co. 

(8) 

1945. TABLES OF FOOD COMPOSITION. U.S. Dept. Agr. Misc. Pub. 572:1-30. 

(9) Burke, Emily P. 

1850. REMINISCENCES OF GEORGIA, viii + 252 pp. James M. Fitch, Ohio. 
(Peanuts p. 126) 
(ID) Chevalier, Aug. 

1934. monographie de l'arachide ch. vii. Rev. Bot. Appl. & Agr. Tropical 

14 (158):833-864. (see p. 840) 

(11) 

1933. MONOGRAPHIE DE L'ARACHIDE. VI HISTOIRE DBS EMPLOYS DE L'aRACHIDE. 

Rev. Bot. Appl. and Agr. Tropical 13 (147):747-7S2. 

(12) COLTON, H. E. 

1872. ABOUT PEANUTS AND PEANUT OIL. Rural Carolinian 3:428-429. 

(13) Dent, John H. 

1850. LETTER TO DIRECTOR OF PATENT OFFICE. Patent Office Rpt. 1849: 

148-149. 

(14) DuTertre, R. p. J. B. 

1667. HISTOIRE GENERAL DES ANTILLES, (ref. p. 121) 

(15) EASBY, W. B. 

1851. LETTER TO COMMISSIONER OF PATENTS. Rpt. Com. Patents 1851 (2): 

353-355. 

(16) Fisher, W. H. 

1946. PEANUTS IN THE FIFTH FEDERAL RESERVE DISTRICT. Research Dept. 

Fed. Res. Bank of Richmond, x -|- 139 pp. Richmond. 

(17) Gasso, J. G. C. 

1855. THE PEANUT, OR PINDAR. Rpt. Com. Patents 1855:259. 

(18) Jefferson, Thomas. 

1904. notes on THE state of VIRGINIA. Works of Thomas Jefferson (Federal 
Edition by Thomas Ford) 3 :408. G. P. Putnam's Sons. 

(19) JOSSELYN. 

1924. NEW ENGLAND'S RARITIES DISCOVERED, (reprinted in) Archaelogia 
Americana 4:121-122. 

(20) 

1924. DESCRIPTION OF THE NOW DISCOVERED RIVER AND COUNTRY OF VIRGINIA 

(reprinted in) Archaelogia Americana 4:60-61. 

(21) MacClenny, W. E. 

1935. HISTORY OF THE PEANUT. Suffolk News Herald. Jan. 18, 1935. 

(22) Paulette, J. C. 

1848. CULTURE OF THE GROUND PEA. Southern Cultivator 6 (3):53-54. 

(23) Philips, M. W. 

1852. LETTER TO COMMISSIONER OF PATENTS. Rpt. Com. Patents. 1852:65-67. 

(24) Ramsey, David 

1809. the history of south Carolina. David Longworth, Charleston. 



ECONOMIC IMPORTANCE OF PEANUTS 17 

(25) Sessions, L. H. 

1942. THE PROBLEMS OF THE PEANUT BUTTER INDUSTRY. National PeanUt 

Council Yearbook, 1942:29-32. 

(26) Utt, C. a. a. 

1914. SOME DATA ON PEANUT BUTTER. Jour. Ind. & Eng. Chem. 6 (9) :746-747. 

(27) Watson, Sir William 

1769. SOME account of an oil, transmitted by GEORGE BROWNRIGG OF 

north CAROLINA. Phil. Trans. Roy. Soc. London. 59:379-383. 

(28) Williams, John Lee. 

1837. TERRITORY OF FLORIDA. 112 pp. A. L. Goodrich, New York. 

(29) WiNTON, A. L. 

1899. PEANUT BUTTER AND PEANOLIA. Conn. Expt. Sta. Rpt. 23:138. 



CHAPTER II 

ORIGIN AND EARLY HISTORY 
OF THE PEANUT 

By 
B. B. HIGGINS* 

What are the origin and the history of the cultivated peanut, and what 
are its close relatives in the plant world? One would think that a plant 
with such striking botanical characteristics and with such economic possi- 
bilities could not long escape notice of botanists or of those interested in 
production of food crops, and that these questions would be readily answer- 
able. However, the New World presented to the eyes of explorers and 
colonists so many new plants: Indian corn, Irish potato, sweet potato, 
cassava, cacao, beans, tobacco and many other plants of even greater 
interest that the peanut received scant attention. Consequently, the origin, 
history, introduction into various countries, and the affinities of the culti- 
vated peanut are still hazy. Many points have been cleared during the 
past 25 years and with the accelerated investigations now in progress 
much more information should be available within a decade. 

In 1933, August Chevalier (6) wrote, "le prohleme de le origine de 
I'Arachide a fait couler des flats d'encre." ( Translation : The problem of 
the origin of the peanut has made floods of ink flow.) During the nine- 
teenth century a number of authors attempted to prove that the peanut 
originated in Africa and cited plants with subterranean fruits described by 
Theophrastus and Pliny as occurring in Egypt and other Mediterranean 
countries. Chevalier (6) has summarized the opinions of various students 
as to the identity of these plants and the evidence is conclusive that neither 
Pliny nor Theophrastus saw or mentioned the plant now known as 
Arachis hypogaea. The Arachidna of the ancient Greeks was evidently 
applied to a species of Lathyrus, Arakos referred to Lathyrus tuberosa, 
the Ouiggon mentioned by Theophrastus as occurring in Egypt was 

< B. B. Higgins is botanist, Georgia Agricultural Experiment Station. 

18 



ORIGIN AND EARLY HISTORY OF THE PEANUT 19 

Calocassia antiquorum, and the Oetium of Pliny referred to Cyperus 
esculentus. Arachis hypogaea was introduced into Egypt only in recent 
times as indicated by the vernacular name "ful Sudani." The confusion 
was accentuated by the fact that the name Arachidna was used for the 
peanut by several naturalists and voyagers near the close of the seven- 
teenth century. 

Likewise, there is nothing to support the suggestion of Asiatic origin. 
Tradition in China and in India indicates recent introduction into the 
Asiatic mainland from the Philippine Islands or other of the South Pacific 
Islands. 

Many attempts have been made to trace the distribution of the peanut 
through the vernacular names which might have been passed from one 
locality to another with seed of the plant. Chevalier (7) lists several hun- 
dred but, with few exceptions, these are local names which in that dialect 
are more or less descriptive of the seed or fruits of the plant as, for ex- 
ample, the English names, peanut, groundnut, and groundpea ; the French, 
"pistach du terre," {ground pistache) ; and the Portuguese, "Amendoim." 
Exceptions to be cited such as "pindar" and "goober" are undoubtedly 
corruptions from some African names by African-born slaves who had 
known either the peanut or Voandzeia in Africa. The two common names 
in use in Spanish-speaking countries are: "Cacahuate," used in Spain 
and Mexico, derived from the Nahuatlan (Aztec) name "tlalcacahuatl" 
(earth cacao) ; and the other, "mani" used throughout Spanish America 
except Mexico, is Thalail name heard by the Spaniards in Hispanola, 
now Haiti-Santo Domingo. The Brazilian name "Mandubi" is apparently 
derived from the Indian name which is variously written from the Indian 
articulation as "Mandobi," "Manobi," "Mun dubi," "Mondorvi" and 
"Minui." 

In 1838, Bentham published his "Flora Braziliensis" describing five 
species of Arachis, all from Brazil. This caused botanists generally to take 
with favor the claim for American origin of the cultivated A. hypogaea L. 
because, as stated by A. de CandoUe (4), "A genus with all its known 
species thus confined to a single region of America can hardly have a 
species common to both the New World and the Old. That would be too 
great an exception to a common principle of phytogeography." But posi- 
tive proof as to American origin came with the discovery of peanuts, 
similar in appearance to varieties now grown in Peru, in ancient graves 
excavated at Ancon, Pachacamac, and other points in the desert region 
along the coast of Peru, about 1875. E. G. Squier (21), a United States 
Commissioner to Peru, gives a vivid description of these burial grounds : 



20 THE PEANUT— THE UNPREDICTABLE LEGUME 

"During my residence in Lima, I visited the ruins of Pachacamac, twenty- 
miles south of the capital. . . . Pachacamac is one of the most notable spots 
in Peru, for here, as we are told by the old chroniclers, was the sacred 
city of the natives of the coast before their conquest by the Incas. ... In 
Pachacamac, the ground around the temple seems to have been a vast 
cemetery. Dig almost, any where in the dry nitrous sand, you will come 
upon what are loosely called mummies, but which are the desiccated 
bodies of the ancient dead. ... I will record what I found in a single tomb, 
which will illustrate how a family, not rich, nor yet the poorest, lived in 
Pachacamac. . . . Besides the bodies there were a number of utensils, and 
other articles in the vault; among them half a dozen earthen jars, pans 
and pots of various sizes and ordinary form. One or two were still in- 
crusted with the soot of the fires over which they had been used. Every 
one contained something. One was filled with groundnuts familiar to us 
as peanuts." Since the coast tribes occupied this region before develop- 
ment of the Incan Empire, some archaeologists consider these graves as 
possibly antedating our Christian era, but overlapping of the various 
culture periods of the area makes dating of the graves uncertain. There 
can, however, be no doubt that they are very ancient, certainly pre- 
Columbian. 

Monardes (16), who lived in Peru about 1550, described briefly the 
subterranean fruits without giving a name for the plant. He said it was 
grown along the Maranon River and was highly esteemed by both 
Indians and Spaniards. 

Garcillosa de la Vega, son of an Incan princess and a Spanish father 
and born in Peru in 153^, published in 1609 his "Los Commentaries 
Reales" in which mention is made of "ynchic" as an important food of the 
Incas. 

Thus, Peru has become conspicuously associated with the peanut, 
and development of the cultivated forms is frequently cited as one of the 
accomplishments of the Incas; but continued study of old manuscripts 
has shown that cultivation of the peanut was by no means confined to 
Peru and Brazil at the time Columbus visited the New World. It is of 
interest in this connection to remember that the two common names for 
the plant in Spanish-speaking countries, "mani" and "cacahuate," are of 
North American origin. 

Las Casas (5), a priest who lived in "New Spain" (now Haiti-Santo 
Domingo) from 1510-1530, mentioned "mani" among the food plants 
being grown by a tribe of Indians on the island. Likewise Oviedo (17), 
the official historian of "New Spain" 1513-1524, mentioned "mani" as 



ORIGIN AND EARLY HISTORY OF THE PEANUT 21 

one of the important food plants very commonly grown by the Indians of 
"New Spain" and other islands of the West Indies. The complete record 
follows: "Del mani, que es cierto genero de fructa e mantenimiento 
ordinario que tienen los indios en esta Isla Espanola e otras islas destas 
Indias. 

"Una fructa que tienen los indios en esta Isla Espanola, que llamen 
inani, la qual ellos siembran, e cogen, e les es muy ordinaria planta en 
sus huertos y heredades, y es taraana como pinones con cascara, e tienenla 
ellos por Sana : los chripstianos poco caso hacen della, si no son algunos 
hombres baxos, o muchachos y eschlavos, o gente que no perdona su 
gusto a cosa alguna. Es de mediocre sabor e de poca substancia e muy 
ordinaria legumbre a los indios, e hayla en gran cantidad." ( Translation : 
"Of the peanut, which is a certain kind of fruit in common use by the 
Indians in this Isla Espanola and other islands of the Indies. A fruit 
which the Indians in this Isla Espanola have, they call mani (peanut) 
and they plant it, and harvest it and it is a common plant in their gardens 
and fields, and it is the size of a pine nut with a shell, and they think it is 
healthful ; the Christians pay little attention to it, unless they are common 
people, or children, or slaves, or people who do not have a fine taste. It 
is of mediocre taste, and little substance, and is a very common food of the 
Indians who use it in quantity.") 

About the same time (1518-1521) Cortes conquered Mexico and this 
was quickly followed by exploration and colonization. Many voluminous 
reports on the natural resources of the country apd on the Aztec civiliza- 
tion and customs were sent to the king of Spain. Few of these early docu- 
ments have been available for study and no clear-cut picture of the cul- 
ture and use of peanuts by the Indians of Mexico has been obtained. In 
reporting on medical practice among the Aztecs, Sahagun (19), historian 
and instructor in a mission school at Tlatalalco, 1529-1590, mentioned use 
of tlalcacauatl (Nahuatlan name for peanut, from tlatle = earth and 
cacauatl = cacao seed) as a poultice for swollen gums ; but he did not list 
it under this name among the plants used for food. 

Jean de Leary (15), who lived at Rio de Janeiro about 1555, pub- 
lished a description of the fruits undei: the Brazilian Indian name 
"manobi." According to Filcalho (11), it was again noted in Brazil in 
1570 by Gabriel Soares de Souza, and again in Peru about the same time 
(1571) by Joseph de Acosta (1). 

During the next 200 years the plant was described or mentioned by 
many botanists and explorers in the New World, and by botanists in 
Europe ; but it was not until about 100 years ago that the range of the 



22 THE PEANUT— THE UNPREDICTABLE LEGUME 

wild species began to be extended beyond the borders of Brazil. Since 
then the wild species have been found abundantly distributed from the 
Amazon River through Brazil, Bolivia, Paraguay, Uruguay and northern 
Argentina to about 35° south latitude. The wild species of Arachis form 
an important part of the herbage for supporting the vast herds of cattle in 
this region. Some species seem especially adapted to growth and survival 
in hard clay soils and under conditions of close grazing. Others occur 
mostly in loose-textured sandy or alluvial soil. The cultivated forms are 
even more widely distributed and appear to be especially numerous and 
diverse in northern Argentina. E. C. Clos (9), in 1939, published on the 
types of cultivated peanuts, apparently indigenous to Argentina. He as- 
sembled 46 collections, including those grown commercially as well as 
those grown by various groups of Indians. These were grown and 
grouped according to characteristics such as: Vine type, bunch or 
runner ; pod size and shape ; size and number of seed ; and color of seed 
coat, black, red, flesh, white, and white with red splotches. The 46 
strains appeared to be quite homogenous and fell into IS distinct classes. 

There is considerable evidence indicating that the cultivated forms of 
the peanut originated in the Gran Chaco area including the valleys of the 
Paraguay and Parana rivers, and were at an early date distributed 
throughout the tropical and subtropical regions of both South and North 
America. 

The various Indian tribes were not so isolated as one might suppose. 
In this connection, it is of interest to remember the Incan legend that they 
came to Peru from the South; also that the Incan Empire included a 
part of northern Argentina well east of the Andes. Archaeologists and 
ethnologists are convinced that a great influx of South American Indians 
came to Central America in a pre-Maya era. Central American Indians 
told the Spaniards of the fabulously wealthy Incas in Peru and of the 
great cities of the Aztecs in Mexico. Apparently there were regular trade 
routes between the Aztecs and the pueblo-dwelling tribes in what is now 
New Mexico. Archaeologists (13) also find evidence of communication 
between the Indians of the West Indies and those of the entire Gulf 
Coast. 

It is not unbelievable, therefore, that the peanut was carried by the 
Indians to most areas suited to its culture, just as they spread corn, 
bean, pumpkin, cassava, sweet potato, and Irish potato. 

How can we account for rapid establishment of peanut culture in other 
portions of the world, particularly in Africa and in Asia ? 

Chevalier (6) reviewed the argument of Brown, Ficalho, and Wiener 



ORIGIN AND EARLY HISTORY OF THE PEANUT 23 

supporting the contention that Arachis hypogaea was indigenous in 
Africa, and concluded that there is absolutely no proof of the presence of 
this plant in Africa in pre-Columbian times. Continuing, he says that 
after 1502 communication between the west coast of Africa and Brazil 

'was frequent. Portuguese ships going to Brazil always touched the 
African coast to take on fresh water and food, and the return trip was 
made by the same route. Naturally, having established colonies and trad- 
ing posts on both coasts, the products of each were introduced to the 
other country. They introduced the African Voandzeia subterranea into 
Brazil wh^re it was grown to some extent under the name "Mandubi de 
Angola." Pedro Alvares Calval, sailing for India with a large fleet, swung 
too far west and touched the Brazilian coast on April 22, 1500. He took 
possession of the land in the name of Portugal, then sailed on around the 
Cape of Good Hope to the East Indies. After this time, the Portuguese 
were very active in exploration and establishment of trading posts in 
Brazil, in Africa, and in the East Indies. Apparently they introduced 
maize, cassava, tobacco, and peanuts to the coasts of Africa. All four 
spread so rapidly that travelers in Africa a hundred years later thought 
all indigenous to Africa. It seems likely that the Portuguese introduced 
the plants at many points along the African coast, since they had already 
established small colonies and trading posts even along the east coast of 
Africa prior to 1522, when Juan Sebastian del Cano, in command of the 
"Vittoria" in the final lap of Magellan's voyage around the world, feared 
to put in a:t any point along the African coast, although many men of his 
crew were dying of starvation; because he feared interception by 
Portuguese. 

Both Portuguese and Spaniards probably carried peanuts to the East 
Indies during the early years of the sixteenth century. Waldron (23) and 
others have suggested that the peanut was carried to the Philippines and 
the Moluccas by Magellan on his circumnavigation trip, but this seems 
hardly probable. According to Pigafetta's (18) account, Magellan's fleet 
wintered at Port St. Julian, southern Patagonia, and the following spring 
passed through the Strait of Magellan and then sailed west-northwest 
for 3 months and 20 days without seeing land. He did not touch Peru as 
suggested by Badami (3). Since his crew was reduced to eating rats, 
sawdust, and leather from the ship's rigging, they certainly would have 
eaten any peanuts that were aboard. Furthermore, Pigafetta does not 
mention any seed or any agricultural products among the articles traded 
or presented to the islanders. He did mention that Chinese trading vessels 

\ visited the islands during Magellan's stay. After Spanish colonization of 



24 THE PEANUT— THE UNPREDICTABLE LEGUME 

the Philippine Islands, the islands were governed from Mexico and a 
regular trade route was established between them and the west coast of 
Mexico, and it would seem likely that peanuts were carried there from 
Mexico. 

The statement that the peanut was not known in North America until 
introduced on slave ships from Africa has been made so frequently that 
we have accepted it as true, in spite of the evidence that it was being 
grown in Mexico and Central America (12, 19, 23) as well as in various 
islands of the West Indies before the arrival of Europeans. This state- 
ment was based upon a single paragraph in which Hans Sloane (20), in 
his natural history of Jamaica, mentioned peanuts grown by Mr. Harri- 
son from "Guinea seed" and ignores the fact that he mentioned other 
collections. The first reference to the plant is in Volume I, pages 72 and 
73, under the paragraph heading : "Arachidna Indiae utriusquetetraphylla 
Par. Bot. pr. p. 314." Then follows the synonomy with 36 references and 
ends with the statement: "In Caribearum Insularum una banc plantam 
collegi, sed qua non memini." (Translation: I collected this plant on one 
of the Islands of the Caribbean, but which (one) I do not remember.) 

On page 184 we find the commonly noted reference: "XXII. 
Arachidna Indiae utriusquetetraphylla. Par. Bot. pr. cat. p. 72. Mandobi 
fructus pisonis Mus. Swammerd. p. IS. An Terfez. Ogilb, Africa p. 22. 
I found this planted from Guinea seed, by Mr. Harrison, in his Garden 
in Liguanee. The fruit, which are called by seamen earthnuts, are brought 
from Guinea in Negro ships, to feed the Negroes withal in their voyage 
from Guinea to Jamaica. . . . An oil is drawn out of them by expression, 
as good as that of almonds. . . . This is the nut Clusius speaks of, 
wherewith the Portuguese victual their slaves to be carried from St. 
Thome to Lisbon." 

Reference is also made in Volume II, page 369 : "Mandubi quadri- 
folium Americanum fructus subterraneous flore luteo Amenduinas 
Lusitanorum. Surian. An Junsa Linchot. cap. 8, or cap 6, C.B. Pin. 346? 
Arachidna quadrifolia vellosa flore luteo. Plum. pi. Amer. p. 49. Pasta- 
ches des Isles, autrement Manobi Labat. T. 4 p. 49. Mr. Barham says, in 
his observations, they are eaten raw, roasted, or boiled and never occa- 
sion any headache." 

There are other incidental references, but each of these three notes 
evidently refers to different collections and indicates clearly that peanuts 
were commonly grown in the islands visited by Sloane, and probably of 
more than one type. It seems probable that he mentioned the peanut 



ORIGIN AND EARLY HISTORY OF THE PEANUT 25 

grown by Mr. Harrison from "Guinea seed" because it differed from 
those commonly found in the Caribbean Islands. 

Du Tertre ( 10) gave a very good description of the peanut plants so 
that one can easily recognize the runner type, pods with two or three 
seed with red seedcoats. This same type of peanut was also observed by 
Labat (14) and described as apparently a wild plant on Guadeloupe in 
1697. 

^ Apparently the Indians of the West Indies and those of the Florida 
mainland had occasional contacts and in this way the Florida Indians 
probably .obtained the peanut. However, proof of the pre-Columbian 
presence of peanuts in either Florida or the Texas-New Mexico area has 
not yet been found. 

The records found to date are not clear as to the origin of the various 
types grown in the United States. Several authors mentioned importa- 
tion, for the New York market, of peanuts from Africa ; and the small- 
seeded runner, known successively as African, Wilmington Runner, 
North Carolina Runner, Georgia Runner, Southeastern Runner, etc., 
very probably came from Africa. The Spanish variety was imported 
from Spain in 1871 (2). Valencia was probably received from the same 
source. The origins of the Virginia type, the Tennessee Red, and the 
Tennessee White are still uncertain. The two latter resemble closely the 
peanuts most commonly grown in Mexico and Central America. Che- 
valier (8) described A. hypogaea L. var. macrocarpa A. Chev. to include 
Jumbo, Virginia Runner, Virginia Bunch and Samatiga, with Jumbo as 
the type. He states further that Jumbo originated at Bahia, Brazil, but 
failed to indicate the authority for this statement. Jumbo, as known in the 
United States, is not a variety distinguishable from Virginia Runner and 
Virginia Bunch. It should be thought of as a large-seeded strain of 
either Virginia Runner or Virginia Bunch and considered as a market 
classification rather than a variety of peanuts. 

SELECTED REFERENCES 

(1) acosta, jose de. 

157l historia natural t moral de las indias. 

(2) Anon. 

1898. JOURNAL OF COMMERCE (NORFOLK, VIRGINIA). November 5. 

(3) Badami, v. K. 

1935. arachis hypogaea linn. groundnut or peanut. original habitat 
AND ITS DISTRIBUTION IN THE WORLD. Jour. Mysore Agr. and Exp. 
Union IS (4):141-1S4. 



26 THE PEANUT— THE UNPREDICTABLE LEGUME 

(4) Candolle, Alphonse de. 

1882. l'origine des plants cultivees. 

(5) Casas, Bartolome de las. 

1909. APOLOGETIC HiSTORiA DE LAS INDIAS. Serrano y Sanz ed. Madrid, 
("Mani" p. 29). 

(6) Chevalier, Aug. 

1933. HISTOIRE DE l'arachide. Rev. Bot. Appl. & d'Agr. Trop. 13 (146 & 
147):722-752. 

(V) 
(8) 



1933. NOMS vernacular de l'arachide dans LES DIFFERENTS PAYS. Rev. 

Bot. Appl. & d'Agr. Trop. 13 (146 & 147) :740-747. 



1933. LE GENRE ARACHIS ET SA SYSTEMATIQUE. Rev. Bot. Appl. & d'Agr. 

Trop. 13:753-789. 
(9) Clos, E. C. 

1939. los tipos de mani cultivados en la argentina y su distribucion 
GEOGRAPHICA. Phisis 18:317-329. 

(10) Du Tertre, R. p. J. B. 

1667. HISTOIRE general DES ANTILLES, (ref. p. 121) 

(11) Filcalho, de 

1884. plantas uteis de Africa portugueza. Lisbon. 

(12) Gregory, C. V. 

1929. FARMING through THE AGES. FIRST FARMERS OF AMERICA. Prairie 

Farmer 101:77, January 19, 1929. 

(13) Krieger, H. W. 

1931. aboriginal indian pottery of the dominican republic. u.s. nat. 
Mus. Bul. 156, 165 p. 

(14) Labat, R. P. 

1742.VOYAGE aux iles d'amerique. 4:365-369. 

(15) Leary, Jean de. 

1578. HISTOIRE d'un voyage fait en la terre du bresil, autrement dit 
amerique. La Rochelle. 

(16) Monardes, N. 

1574. DE SIMPLICIBUS MEDICAMENTIS ex OCCIDENTALI INDIA DELATIS, QUORUM 
IN MEDICINA USES EST. 88 p. 

(17) OviEDO Y Valdes, Gonzalo Fernandez de. 

1944-45. HISTORIA general y natural de LAS INDIAS. 14 vols. Asuncion, 
Paraguay, (ref. Vol. 2:176) 

(18) Pigafetta, Antonio. 

primo viaggio intorno al mondo. in blair and robertson. the 
Philippine Islands, Vol. 33. 

(19) Sahagun, Bernadino de. 

1946. HISTORIA GENERAL DE LAS COSAS DE NUEVA ESPASfA. 3 Vols. MexicO. 

(ref. Vol. 2:262-263.) 

(20) Sloane, Hans. 

1698. CATALOGUS PLANTARUM QUOQUE in insula JAMAICA sponte prove- 
NiUNT, VEL VULGO COLUNTUR, ETC. D. Brown, Temple Bar. London. 



ORIIGIN AND EARLY HISTORY OF THE PEANUT 27 

(21) Squiee, E. G. 

1877. peru; incidents of travel and exploration in the land of the 
INCAS. New York. 

(22) Verrill, Alpheus. 

1937. THE MIGHTY PEANUT. Foods America gave the world. Vol. 1, p. 95-100. 

(23) Waldron, R. a. 

1919. THE PEANUT (aRACHIS HYPOGAEA) ITS HISTORY, HISTOLOGY AND 

UTILITY. Contr. Bot. Lab. Univ. Penna. 4:301-333. 



CHAPTER III 



MORPHOLOGY , GENETICS AND 
BREEDING 

By 

WALTON C. GREGORY, BEN W. SMITH AND 
JOHN A. YARBROUGH^ 

Beginning with Oviedo's (47) account of the West Indies published in 
1535 and Schmidel's (64) description of his travels in the La Plata Basin 
during the ye^rs 1534 to 1554, the reader of the peanut literature is con- 
fronted with works in Japanese, Chinese, Dutch, Danish, German, 
French, Bulgarian, Russian, Italian, Spanish, Portugese, and English. 
Here and there, keen observers have recorded their findings regarding the 
structure and development of the peanut plant, only to have them buried 
in the passage of time by an accumulation of inaccuracy and trivia. 
These inaccuracies have been doubly impressed upon the writers 
who find that the 77 titles listed at the end of this chapter omit little 
indeed of the information contained in the 700-800 references at their 
disposal. 

Prior to 1949 we have found only a single description (which was 
wrong!) of the morphology and development of the seed and seedling, 
only two inadequate descriptions of the internal reproductive morphology 
of the peanut, and only a few correct accounts of the relationship between 
the aerial flower and the subterranean fruit. In 1569 Monardes (45) was 
so confused by the subterranean occurrence of peanut fruits that he 
failed to associate these with the plant at all ! A century later Marggraf 
(43) illustrated the fruits as growing on the roots! The first accurate 
description of the peanut flower was pubhshed by Poiteau (52) in 1806 
and confirmed by Richard in 1823 (58), but Bentham's (10) erroneous 

1 Walton C. Gregory is Professor of Agronomy, North Carolina State College, Ben W. Smith is 
Associate Professor of Agronomy, North Carolina State College, and John A. Yarborough is 
Professor of Biology, Meredith College. 

28 



MORPHOLOGY, GENETICS AND BREEDING 29 

interpretations of 1839 are still to be found in many recent textbooks. 

Beginning with a consideration of the peanut seed and seedling and 
passing to the mature root, stem and leaf, this chapter then deals with 
the reproductive morphology of the plant and concludes with a discus- 
sion of its genetics and breeding. Without attempting to cite all the 
known references which have some bearing on the topics discussed, the 
writers have attempted to cover the topics themselves with as much 
thoroughness as existing knowledge permits. This chapter does not in 
any sense represent a botanical or genetic monograph on the genus 
Arachis but does summarize botanical and genetic information as it re- 
lates to a single species of the genus. It is our purpose to present the 
status of knowledge on peanut morphology, reproduction, variation, and 
breeding. 

SEED AND SEEDLING 

Outstanding features of the seeds of cultivated peanuts are their 
variable sizes, colors, and shapes. They may be red, white, purple, pink, 
flesh, rose, tan, light brown, or even red and white. The actual range of 
seed size in peanuts is probably unknown, but we have seen and planted 
seed ranging from 0.2 of a gram to 10 times that size. Seeds may be 
almost spherical, elliptical or much elongated. 

Each seed is composed of two massive seed leaves (cotyledons) , upper 
stem axis and young foliage leaves (epicotyl), and lower stem axis and 
primary root (radicle). A thin papery seed coat covers the seed (figure 
1). In contrast to most papilionaceous legumes the axis of the embryo 
proper is straight. All of the leaves and above-ground parts which the 
seedling will have for the first 2 to 3 weeks of growth are already present 
in the dormant seed. The epicotyl consists of three buds, one terminal and 
two cotyledonary laterals. In the terminal bud there are four foliage 
leaves and in the cotyledonary laterals one or two leaves. Thus the dor- 
mant embryo has from six to eight differentiated leaves, all of them 
ready to expand and go to work immediately upon germination (76). 

When peanut seeds are put to germinate at 80 °F. the radicle appears 
after 24-36 hours. Reporting from Senegal, Bouffil (13) stated that 
hardly 2 days elapse before the appearance of the radicle. In Germany 
Richter (59) found that 8 to 10 days were required for germination in 
damp sphagnum in the hothouse. In outdoor plots at Raleigh, North 
Carolina, 8 to 10 days were required for emergence. Discrepancy be- 
tween the appearance of the young root (24 to 48 hours) and the ap- 
pearance of the shoot (8 to 10 days) is caused by a striking difference in 



30 THE PEANUT— THE UNPREDICTABLE LEGUME 

the initial growth between shoot and root. The root grows very rapidly, 
reaching a mean length of 46 mm. in 4 days (Bouffil, 13) and 100 to 400 
mm. in 4 to 5 days ( Yarbrough, 76) . During the first 2 days of this rapid 
root growth no lateral roots develop (figure 2). But by the time the 




Figure 1. — Mature peanut seed. One cotyledon has been removed to show the 
straight embryo with its well developed epicotyl and massive radicle. The papery 
seed coat is visible around the edge of the cotyledon. 

seedling is 4 to 5 days old, 25 to 50 lateral roots have appeared (Yar- 
brough, 77^. Figure 3 shows the hypocotyledonary axis grown to a 
length of 164 mm. while the entire epicotyl has not exceeded the length of 
the cotyledons, about 20 mm. ; in other words, an epicotyl-hypocotyl 
ratio of J^. In 11^ days this root system reaches a length of 30 cm. and 
produces 100 to 116 laterals (figure 10). Meanwhile the shoot expands 



MORPHOLOGY, GENETICS AND BREEDING 3] 




Figure 2. — Peanut seedling, 2 days old. The well defined collar below the smooth 
hypocotyl marks the region of transition from root to stem. Lateral roots are 
absent and soil particles cling to the roughened surface of the primary root. 
(after Yarbrough, 76.) 



32 THE PEANUT— THE UNPREDICTABLE LEGUME 




Figure 3.— Peanut seedling, five and one-half days old. The epicotyl barely exceeds 
the cotyledons but hypocotyl and primary root have a total length of 164 mm. 
Note the distinct collar at the transition region and the belated appearance of 
lateral roots, (after Yarhrough, 76.) 



MORPHOLOGY, GENETICS AND BREEDING 33 

the foliage leaves laid down in the seed, but no new growth is visible 
until about 21 days after planting. 

ROOT 

In a young peanut seedling the root is sharply differentiated from the 
hypocotyl by an abrupt constriction (figures 2 and 3). This constric- 
tion or collar marks precisely the transition zone (59, 76). Just at this 
collar the intact epidermis of the hypocotyl gives way to the non-epi- 
dermal outer layers of the primary root. Even superficial examination 
reveals the fact that no true epidermis exists on the peanut root. Figure 
2 shows the soil clinging to the broken, sloughing surface. This condition 
in peanut roots, and its expected morphological corollary, the absence of 
root hairs, have been observed by Pettit (50) and Richter (59). Richter 
suggested that the ragged, uneven surface of peanut roots, where the 
root hairs would normally be expected to occur, served as an active ab- 
sorptive surface. Waldron (75) reported root hairs on peanilts and 
showed that under ordinary conditions they usuallyt appeared as rosettes 
of hairs at the junctions of the lateral and main roots; but Reed (55) re- 
ported that few hairs occurred under field conditions. The internal de- 
velopment and differentiation of tissues in the peanut root were first 
touched upon by Richter in 1899. Yarbrough (76) has recently published 
a description. of their internal development. 

A longitudinal section through the growing tip of a young root 
shows the root cap, root initials, stele, and cortex. Among the root initials 
there is no specific differentiation into initiating layers. The root cap, 
cortex, and stele are laid down by the initials most proximal to these 
areas by appropriate longitudinal, tangential, or radial divisions. 

The absence of epidermal initials ultimately results in the absence of 
an intact epidermis and, consequently, the almost complete lack of root 
hairs. The cross section in figure 4 shows that outside the cortex there 
is a cork cambium-like region which by both radial and tangential cell 
divisions lays down the closely packed absorbing cells which Richter be- 
lieved substituted for root hairs as absorbing surfaces. The sloughing ex- 
ternal cells are thus continually supplied from within. This region of the 
root extends only 8 to 10 mm. back from the root cap and has been shown 
to be an actively absorbing region in dye absorption studies by both 
Richter and Yarbrough. Yarbrough emphasizes the probability that the 
importance of this region. in absorption is confined to mineral ions, a fact 
of considerable significance when one considers the ultimate position of 
such maristems in the mature root system. With respect to the limited 



34 



THE PEANUT— THE UNPREDICTABLE LEGUME 



occurrence of root hairs, Yarbrough's results confirm those of Badami 
(3) and Waldron (75) that both high temperature and high humidity 
favor their production. 

If one examines a cross section of the root (figure 4), it can be seen 
that the innermost row of cortex cells constitutes a typical endodermis. 





T»7-. 






w 

.■■J 

:J- • 

« 



'ri' 



.-'•■■'J 



^% 



Figure 4. — Primary root of peanut seedling, cross section; s, stele; c, cortex; m, 
meristematic zone; si, sloughing outer cells. No epidermis is present on the 
root, (after Yorbrough, 76.) 



MORPHOLOGY, GENETICS AND BREEDING 



35 



The central cylinder of the primary root differentiates pericycle, phloem, 
xylem, and pith in normal fashion. The phloem fibers occur in four 
homogeneous bands. These mature about the same time or a little later 
than the last primary xylem. Thus the primary vascular structure of the 
root is tetrarch, external evidence of which can be seen in the 4-ranked 
arrangement of the first lateral roots. 




Figure S.— Older primary root of peanut, cross section. Secondary wood has ap- 
peared ; cortex and pith have begun to disintegrate, (after Yarbrough, 76.) 



36 THE PEANUT— THE UNPREDICTABLE LEGUME 

Yarbrough (76) emphasizes the following characteristic features of 
the root system in the young peanut seedling : 

1. The central stele shows a tetrarch or four-pointed pattern of four 
xylem groups with alternating phloem groups. This is the usual radial 
arrangement of conducting tissue found in roots of all higher plants. 

2. Although Compton (19) stated that the peanut root has no pith, 
note the large pith in the center of the cross section shown in figure 4. 
Old roots are quite woody and the pith breaks down, leaving the root 
hollow. 

3. Old roots have their internal structure modified by two meri- 
stematic zones : (a) the cork cambium which develops from the pericycle 
and causes the death and loss of all tissues external to it, and (b) the 
vascular cambium which develops within the phloem and forms consid- 
erable amounts of wood (figure 5). 

4. Sparsely scattered hairs may be seen on peanut roots under con- 
ditions of high temperature and high humidity with rosettes of hairs more 
common at the bases of some lateral roots. 

5. No true epidermis exists on peanut roots. 

TRANSITION FROM ROOT TO STEM 

The hypocotyl, that portion of the peanut stem below the cotyledons 
and above the root, never emerges from the soil and thus becomes part 
of the anchoring root system of the plant. The transition from root to 
hypocotyl, however, is marked and abrupt, both internally and externally. 
The transition from radial to collateral bundles was described by Richter 
(59), by Compton (19) and by Yarbrough (76). According to Yar- 
brough, ". . . there are four exarch xylem groups in the upper primary 
root; just below the collar there are eight endarch groups formed by 
division of each original one ; in the collar or slightly above some fusions 
may reduce the xylem groups to seven, six, or even four ; above this level 
and throughout the hypocotyl further branching and anastomosing cause 
the number of xylem groups to vary from nine to eighteen." The four 
phloem groups of the primary root pass through the zone of xylem 
transition without modification but finally divide and with the associ- 
ated xylem give rise to the collateral bundles of the hypocotyl. Externally, 
at the collar the smooth, intact epidermis of the hypocotyl gives way to 
the sloughing outer surface of the root. Internally, special tannin cells are 
associated with collateral strands throughout the stem and in leaves, 
flowers, and fruits. These disappear abruptly at the collar. Thus the 
transition zone from root to stem is defined by : 



MORPHOLOGY, GENETICS AND BREEDING 37 

1 . The abrupt out-swelling of the collar. 

2. The sudden appearance of the intact epidermis of the .hypocotyl at 
the collar. 

3. The transition from radial to collateral arrangement of the vascular 
strands. 

4. The immediate appearance of tannin cells associated with the col- 
lateral bundles. 

HYPOCOTYL 

The hypocotyl in the seedling stage is very succulent, white, and 
smooth. The central stele may be quite green even though the hypocotyl is 



y.. 



y 




Figure 6. — Young peanut hypocotyl, cross section midway between collar and 
cotyledons. Note the intact epidermis, wide cortex, stele with collateral vascular 
traces, and central pith, (ajter Yarbrough, 76.) 



38 THE PEANUT— THE UNPREDICTABLE LEGUME 

always underground and the stele is surrounded by a fleshy cortex. In 
the dormant seed most of the radicle is actually hypocotyl tissue and is 
filled with stored food. During germination the hypocotyl, cortex, and 
pith may serve as way-station, storage tissues for food moving out of the 
cotyledons to the roots. 

The hypocotyl, when cut transversely (figure 6), shows an intact epi- 
dermis covered by a thin cuticle, a wide cortex where much stored food 
may be found, and a central stele in which the conducting tissues, xylem 
and phloem, are arranged on the collateral plan. The vascular bundles of 
the hypocotyl increase to nine or more as compared to four in the root and 
surround a large pith. As the hypocotyl becomes older ( 10 to 30 days) it 
undergoes two significant changes, the first of which is a collapse of 
epidermis and much of the cortex. The collapsing layer becomes soft and 
may be easily rubbed off. Secondly, the collar at the base of the hypocotyl 
becomes very woody and hard. The pith breaks down and the hypocotyl 
ultimately becomes a hollow woody axis (76). 

COTYLEDONS 

The position of the cotyledons during germination determines whether 
a seedling is classified as epigeal, i.e., with its cotyledons above the sur- 
face of the ground as in the green bean or the soybean, or hypogeal as 
in the case of the garden or English pea. In the first case the growth of 
the hypocotyl pushes the cotyledons upward until they appear above the 
surface of the soil. In the latter case the cotyledons remain just where 
the seed was placed when planted. Peanuts do neither. The cotyledons 
rise with the hypocotyl' until the soil surface is reached and there they 
stop. Bouffil (13) said that they were hypogeal; Yarbrough (76) said 
that they were not epigeal.. This growth of the hypocotyl which de- 
termines the position of the cotyledons is a function of the depth of plant- 
ing. Bouffil planted seeds of peanuts at depths of 3, 6, and 9 cm., and 
found that the position of the planted seed determined the position of the 
collar, and that the length of the hypocotyl was clearly related to depth 
of planting. Yarbrough (76) has made a similar statement about hypo- 
cotyl length. This fact is strikingly borne out in seedlings volunteering 
in newly ploughed fields in the spring following a crop of peanuts the 
previous summer. Many of these peanuts germinate on the plough sole 
and sometimes must rise 12-14 cm. before reaching the surface. Under 
these conditions the entire food supply from the cotyledons may be 
exhausted and the young epicotyls emerge pale and yellow. When this 
happens it has been consistently noted that with increasing depth of 



MORPHOLOGY, GENETICS AND BREEDING 



39 



planting the hypocotyl length approaches a maximum of 10 to 12 cm. and 
any further elongation necessary for emergence is made by the epicotyl. 
This elongation of the epicotyl does not await attainment of mjiximum 
hypocotyl length but appears to develop continuously in direct pro- 
portion to depth of planting. It has likewise been observed that the length 
of primary root varies inversely with planting depth to such an. extent 
that peanuts germinating at their maximum depth for emergence are 
almost devoid of roots. Bouffil illustrates this clearly in his photograph, 
figure 1, page 10. At ordinary planting- depths the cotyledons (figure 7) 
begin to shrivel (figure 8) as the foods leave them and go into the ex- 
panding root and shoot systems. Twenty days after germination extreme 
shrinkage (figure 9) is apparent. 




Figure 7. — Cotyledon from S-day old peanut seedling, cross section. The abundance 
of stored food at this stage is revealed by the deeply stained cell contents, (ajter 
Yarbrough,76.) 



40 THE PEANUT— THE UNPREDICTABLE LEGUME 

EPICOTYL 

Bouffil (13) divided the life span of the peanut into three stages: 1. 
germination, 2. preflowering, 3. flowering, fruiting, and maturation. The 
first of these covered the period of time necessary for emergence, i.e., in 
Senegal, about 4 days. The period of preflowering extended from the end of 
the first period to the appearance of the first flower, or about 26 days. The 
third stage, flowering, fruiting, and maturation, began with the first flower 
and lasted to maturity or about 80 to 90 days. This life span corresponds to 
the earliest peanuts known to growers in the United States. Comparable 
periods in some of the types grown in America would be 7 to 10 days, 30 
days, and 120 days. 




Figure 8.— Cotyledon from 11-day old peanut seedling, crbss section. In contrast to 
the condition at five days, njuch of the stored food has disappeared and the 
cell contents are lightly stained. Irregular dark patcheis result from the collapse 
of the tissues in these areas, (after Yarbrough, 76.) ' 



MORPHOLOGY, GENETICS AND BREEDING 



41 



The basic morphological pattern of the epicotyl is laid down in the 
seed. Its main axes consists of a central stem and two cotyledonary lat- 
erals ( figure 10) . Contrary to the situation in many plants, at least after 
the first 3 weeks, the main axis of the shoot exerts little inhibitory efifect 
on lateral axes. The main axis develops first but is soon equalled in 
length by each of the two cotyledonary laterals, and eventually may be 
much exceeded by them. From the beginning the plant is provided with 
three active shoot apices. The third and fourth lateral axes arise from 
the central stem subtended by its first two foliage leaves. These no doubt 
are the four branches described by Bouffil (13) but two of them appear 
much later than he indicates. In Virginia type peanuts additional vege- 
tative branch axes commonly arise from the first two nodes of each 




Figure 9. — Cotyledon from 24-day old peanut seedling, cross section. Stored food 
material absent, tissues collapsed and beginning to disintegrate, (after Yar- 
brough, 76.) 



42 



THE PEANUT— THE UNPREDICTABLE LEGUME 




Figure 10. — Peanut seedling, eleven and one-half days old. The root system is well 
developed. Four leaves of the main axis are visible and the two cotyledonary 
lateral branches have begun to expand. All of the shoot organs visible here 
have expanded from fully formed structures of the embryonic epicotyl shown in 
figure 1. (after Yarhrough, 76.) 



MORPHOLOGY, GENETICS AND BREEDING 43 

cotyledonary lateral, subtended by reduced foliar scales known as 
cataphylls. These are found as the first two foliar organs of all lateral 
axes. The cataphyllar internodes are usually short and on the lower 
branches are frequently covered with soil during cultivation. 

In Virginia type peanuts the first reproductive branch generally ap- 
pears in the axil of the first foliage leaf on one of the cotyledonary laterals. 
No reproductive branches occur directly on the main stem in Virginia. 
A reproductive branch may occur in the axil of the second cataphyll but 
none has been reported or observed in the axil of the first cataphyll. The 
first reproductive branches in Spanish and Valencia types occur at the 
first cataphyllar nodes on the cotyledonary leiterals. Later reproductive 
branches also occur on the main stem. 

VEGETATIVE STRUCTURE OF THE MATURE PLANT 

A detailed anatomy of the mature peanut plant has not been written. 
The general morphology, habit of growth, branching habit, and general 
appearance of the plant have been described with varying degrees,' of 
thoroughness. Much of this description is to be found in the taxonomic 
treatments of the genus and its relatives. Although we are not primarily 
concerned here with the systematics of peanuts, we find the published 
descriptive accounts of the species one of our best sources of general 
morphological information. 

Root 

Hoehne (34) has described the genus as perennial. The root systems 
of all the wild species develop much-branched, woody structures and all, 
including our cultivated form, last more than one year. In A. hypogaea 
the root system may penetrate to a depth o f 3 to 4 feet in cultivated 
fields (Yarbrough 76). In some wild species the root systems become 
tuberous and fleshy (figure 11). This characteristic is not confined to A. 
tuber osa but is also found in A. marginata (34). When grown in the 
United States, wild species received from South America show variable 
development of the tuberous habit, but even in forms generally not 
thought to possess tubers this character is somewhat apparent. Of the 
species seen by the authors, only in A. hypogaea do the roots appear to 
be entirely non-tuberous. At present '^c (Jo not know whether or not 
this character would develop in specimens of A. hypogaea grown for sev- 
eral years. Hoehne (34) considered the tubers to be food storage organs 
which assist in carrying the plants pv^r unfavorable periods of the year, 



44 



THE PEANUT— THE UNPREDICTABLE LEGUME 




Fig:ure IL — Tuberous root system of Arachis marginata. Tap-rooted as in A. hypo- 
gaea, this root system differs from the cultivated species in the development of 
fleshy thickening. 



*i*fcT7*i 




Figure 12.— Root system of Arachis hypogaea. This root system with its well-de- 
veloped tap root may penetrate the soil to a depth of 3-4 feet. Note the abundance 
of lateral roots with fibrous rootlets, but the absence of fleshy thickening. 



MORPHOLOGY, GENETICS AND BREEDING 45 

So far as is known these structures have not been put to practical use 
by rhan. 

The root system in A. hypogaea consists of a tap root with many 
laterals (figures 10 and 12) and adventitious roots from the hypocotyl 
and aerial branches. The nature of the much-branched and vari-formed 
adventitious roots developing from the bacterial nodules (Prevot, 54) 
has not been clarified.* Prevot suggested certain possible functions for 
such roots but these have not been experimentally verified. Some of the 
wild species fr equently d evelop extensive branching roots from the pegs 
(Gregory, 27). A.Ji^^ogaeaJhasheen observed to do this occasionally 
but in s uch cases the roots canjjsually be seen to develop from callus 
tissuejoUowmgjwounding of the peg or pod. The development of root 
hairs has not been studied sufficieritTy in A. hypogaea or at all in the 
wild species. 

Stems' 

The cultivated peanut is ordinarily (1) erect (bunch) or (2) pros- 
trate (running) although intermediate growth forms occur. In both cases 
there is an erect primary branch which serves as the axis of the plant and 
gives rise to various lateral branches. The central axis (rnain stem) de- 
velops from the terminal bud of the epicotyl and is flanked by two oppo- 
site, lateral branches which arise from the respective cotyledonary axils. 
The central axis is always erect but may be relatively short in the pros- 
trate varieties. In the erect varieties the lateral branches are also erect 
or ascending, but even in these types the plants may become semi- 
decumbent as growth proceeds. In contrast, the main lateral branches of 
the truly prostrate vai^ieties always grow peripherally from the main axis 
and usually lie within an inch of the ground except at their tips, which 
may be somewhat ascending. 

Working with cuttings, Harvey and Schultz (29) observed in an 
erect type that main stem and lateral cuttings produced plants which 
were essentially similar in flowering habit to the control plants grown 
from seed. In two other varieties, characterized by non-flowering main 
stems, the main stem cuttings produced no flowers on the original axis 
but produced laterals in a manner comparable to the seedlings. The cut- 
tings of the laterals continued to behave as laterals, however, and pro- 
duced inflorescences on all branches including the initial axis which 
had been cut from the parent lateral. One of these varieties was distinctly 

* In his figure 13, Prevot (54) illustrated a cluster of these roots on which the nodules pro- 
duced a number of white rootlets, having the appearance of roots grown under the influence of 
heteroauxin. These rootlets were thickened, short, and often had claviform ends. It may be 
noted that these roots appear very similar to those infested with nematodes. 



46 THE PEANUT— THE UNPREDICTABLE LEGUME 

prostrate and the cuttings of its laterals not only flowered, but also con- 
tinued to be prostrate, growing entirely in one direction from the original 
point of root attachment. Clearly in this case, the polarity in development 
which controlled the original lateral branch was maintained independently 
in the excised portions. 

The stems of A. hypogaea are angular at first, containing a solid 
pith which breaks down eventually so that old stems are hollow. The 
angularity is also lost with age, the older branches becoming cylindrical. 
There is no indication of woody development in the aerial portions of 
Arachis. The genus consists exclusively of herbaceous perennials; pos- 
sibly some forms of A. hypogaea should be considered annual. 

A variety of other growth forms are found among the wild species of 
Arachis. Hoehne (34) described these briefly in his monograph but at- 
tached little systematic importance to the variation present. The rhizo- 
matous habit is clearly present in A. glabrata, for example, while several 
of the species are stoloniferous, the stolons being partially buried at times. 

The pattern, order, and kinds of branching in the peanut are one of 
the most interesting botanical features of the plant. Richter (59) gave a 
brief description of branching orders wherein he let the central stem jixis 
of the plant be an axis of the n order. Branches arising from the n order 
axis were of m + i order and branches arising from n + 1 order axes 
were n + 2 order, etc. Branches arising in the axils of the foliage leaves 
were of two kinds, (1) vegetative and (2) reproductive. Since repro- 
ductive branches normally do ,not give rise to further branching, their 
production terminated all further orders of branching. For example, in 
Richter's material, w + j order reproductive branches, by their specific 
morphology, terminated the branching system. Prevot's (54) diagram 
in his figure 10 shows a branching pattern similar to the type described 
by Richter (59). We have observed branching systems of several varie- 
ties of A. hypogaea and found that these differed widely not only in the 
numbers of branching orders produced but also because they fell into 
certain well defined patterns. 

Leaves 

Leaves of peanuts are usually pinnate with two pairs of leaflets. 
Hoehne (34) reports that at least one species, and perhaps two are nor- 
mally trifoliate. The leaflets may be elliptic-obovate, {A. hypogaea) , ellip- 
tic-lanceolate, {A. glabrata) or almost linear {A. angustifolia) . The 
leaflets may have inroUed margins or varying development of marginal 
hairs. Hoehne (34) makes extensive use of these characters in his de- 
scription of species. The leaves of the several species may be dark dull 



MORPHOLOGY, GENETICS AND BREEDING 47 

green, dark blue green, pea green or yellow green. In A. hypogaea this 
variation is pronounced and has been shown to be genetic in origin. The 
dark dull green of one tuberous-rooted wild species {A. marginata) has 
not been seen in A. hypogaea but is approached in certain Chinese forms. 
The genetic segregation for depth of chlorophyll green in A. hypogaea 
leads to the general supposition that the variations in leaf color between 
wild species are also genetic in nature and are not primarily a matter of 
mineral nutrition as might be suggested by cultivated fields of A. hypo- 
gaea differing in available nitrogen, calcium, and other mineral elements. 

The arrangement of the leaves on A. hypogaea is intimately associ- 
ated with the branching habit of the plant. The leaves occur alternately, 
one at each node, and describe a 2/5 phyllotaxy (Richter, 59). Embry- 
onic leaves on the main stem axis are well formed and ordinarily saow 
little or no reduction in size. This is far from the case on all primary 
and secondary laterals. As one proceeds towards the base from the tips 
of such branches, the leaves usually show reduction in size and at the 
lowermost nodes also show a reduction in number of parts and complete- 
ness of form until at the first and usually the second node, the leaves are 
represented by mere scales known as cataphylls. Branches arising in the 
axils of the foliage leaves may be either vegetative or reproductive. In 
either case the first two nodes are cataphyllar. 

The morphology of the mature foliage leaf of cultivated peanuts has 
been described rather completely. The leaf is even-pinnate with four 
obovate to elliptical leaflets. Two large, long-lanceolate stipules enclose 
the leaf in the bud. Stomata occur on both surfaces of the leaves. Varia- 
tions in organization of leaves of seedlings and older plants include oc- 
casional quinque-foliate, trifoliolate, bifoliolate, and even unifoliolate 
types. 

Reed (55) illustrated sections of the leaflets and emphasized the 

presen££_i2f_water_stoo^£.j;dkJILjhS-.£E2^ This water 

storage tissue, associated with typical mesophytic leaf structure, led him 
to speculate concerning the intermediate ecological position of the peanut 
betwee n xerophyte and mesophyte. These speculations may prove to be 
well founded, for peanuts are capable of withstanding long periods of 
dry weather but give a typical mesophytic response to relief by rains. 
The peanut's ability to withstand adverse water conditions, its adaptation 
to soils of deep sand, and its geocarpic habit conform to what we know 
of the habits, geographic distribution, and ecology of other geocarpic 
and amphicarpic species. Whether the water storage cells of the leaflets 
play a functional role in this complex of factors is unknown. 



48 THE PEANUT— THE UNPREDICTABLE LEGUME 

REPRODUCTIVE MORPHOLOGY 

Inflorescence 

Kurtz (41) described the inflorescences of the peanut as two to 
three-flowered, occurring in the leaf axils, but Pettit (50) merely stated 




Figure 13. — A well-developed peanut inflorescence; b, bract (cataphyll) subtending 
a floral branch; f, bract (cataphyll) subtending a flower; p. peg; t, terminal 
bud of the inflorescence. An axillary floral branch arises at each node of the 
zig-zag inflorescence axis. The cataphylls have the same relation to the axillary 
branches of this subpaniculate inflorescence as leaves have to the lateral 
branches of a vegetative shoot. 



MORPHOLOGY, GENETICS AND BREEDING 49 

that the flowers develop in the axils of the leaves. Richter (59) described 
the inflorescence w^ith its bracts as an axillary head or compressed spike 
with a 2/5 phyllotaxy in the arrangement of its flowers. 

In systematic treatments of Arachis, the inflorescence is described as 
spicate or subpaniculate. The inflorescences are not terminal but always 
occur in the axils of foliage leaves or cataphylls. They never occur at the 
same nodes with vegetative branches and form with the latter a definite 
branching pattern. Each inflorescence bears three to several flowers. The 
flowers usually appear one at a time but two may open simultaneously 
in the Spanish type. Flowers on the same inflorescence may appear daily 
or at intervals of several days. 

An inflorescence (figure 13) irrespective of whether it arises in the 
axil of a foliage leaf or in the axil of a cataphyll, produces a cataphyll 
at its first node. Each successive node of the inflorescence also has its 
cataphyll in the axil of which arises the simple flowering branch. The 
flowering branch is exceedingly short and possesses a single cataphyll, 
bifid or simple, in the axil of which the flower bud appears to develop. 
The production of the flower terminates further branching. The in- 
florescence can be seen then as a reduced and compressed replica of the 
vegetative shoot reduplicating its phyllotaxy and axillary buds, differ- 
ing largely from the latter in the reduction of organs and the suppression 
of further growth through the production of flowers. The internodes of 
the central axis of the inflorescence may later elongate, producing a 
much expanded fruiting structure. The growing point of the central axis 
occasionally becomes vegetative and pursues a limited amount of 
growth. New inflorescences may then be laid down in the axils of the 
foliage leaves occurring at the end of the original inflorescence. Thus it 
can be seen that what is customarily a reduced and simplified branching 
system sometimes may become so involved that at maturity the untrained 
observer cannot distinguish vegetative from reproductive branches. 

Flower 

The flowers (figure 14) of Arachis are yellow, papilionate, and sessile. 
The development of a remarloible perigyny in volving an unusually long,^ 
hypa nthium or " calyx tube" has led to the erroneous supposition that the 
flowers are long pedicellate. The base of the hypanthium is actually in- 
serted practically at the end of the simple flowering branch and is sub- 
tended directly by its cataphyllar bract. The hypanthium is pubescent. 
The external portion of the tube expands above into five calyx teeth, 
four of which are fused into a superior lip which stands back of the 



so THE PEANUT— THE UNPREDICTABLE LEGUME 

standard. The fifth tooth is linear and lies under the keel. The petals and 
staminal column are adnate at their bases and are inserted together at the 
summit of the tube. The standard is broadly inserted while the wings 
and keel are attached by means of claws. The staminal column is usually 




Figure 14. — A peanut flower as seen in longitudinal optical section. S, standard ; W, 
wing ; St, stigma ; A, anthers ; C. calyx lobe ; K, keel ; T, staminal column ; 
Style; "C tube", hypanthium ("calyx tube") ; O, ovary; Sc, bracts (b and f 
of fig. 13). At lower right the ovary (O) is shown in enlarged section; Ov, 
ovule ; Es. embryo sac. (after Smith, 66.) 



MORPHOLOGY, GENETICS AND BREEDING 51 

composed of ten filaments, eight of which are normally anther bearing. 
The filaments are fused through one-half to two-thirds of their lengths. 
The stamens occur in two series, four bearing oblong, adnate, introrse 
anthers which alternate with four filaments bearing globose, dorsifixed 
anthers. Three of the oblong anthers are biloculate ; the fourth, adjacent 
to the sterile filaments, is usually uniloculate. The four globose anthers 
are uniloculate. In bud stages the filaments bearing the oblong anthers 
exceed the others. The staminal column lies horizontally to the hypan- 
thium. At the point of separation the free ends of the filaments are sharply 
reflexed toward the standard, forming acute angles with their fused 
bases. The pistil consists of a single, sessile carpel (Smith, 66), 1.5 mm. 
long and 0.5 mm. in basal diameter, surmounted obliquely by the long 
filiform style which extends through the hypanthium, bends sharply 
through the staminal column, bends sharply again with the reflexed fila- 
ments, and ends in a club-shaped stigma above the anthers. Near its sum- 
mit on the surface facing the standard, the style is clothed with upward 
slanting hairs. 

Twenty-four hours before anthesis the flower bud is 6 to 10 mm. 
long (Smith, 66). During the day elongation of the bud proceeds slowly 
but when night falls elongation accelerates. At the time of anthesis, near 
sunrise the following day, the flowers may be from 50-70 mm. long. The 
oblong anthers dehisce just before, sometimes after petal expansion. The 
globose anthers dehisce subsequent to further elongation of their filar 
ments, which eventually equal or exceed those of the oblong group 
(Badami, 3; Smith, 66). 

Peanut flowers which are fresh and turgid at sunrise are usually 
wilted by midday, although they last longer in cool weafher. On the day 
after flowering all the flower parts except the small, sessile ovary have 
withered, as Didrichsen (22) clearly demonstrated in 1866. The hy- 
panthium soon abscisses leaving a circular scar at the base of the ovary. 
The old flower parts sometimes adhere to the tip of the ovary during early 
peg growth. 

C ^^'^ J 

The p e g is the most distin ctive featureof the peanut plant, for it is 
by means of this structure that the aerial -flowers come to mature„their 
fruits underground (figure 15). The peg has been variously described as 
an apetalous flower or more recently as a gynophorg, a stalk upon which 
the ovary rests^JThe various interpretations and terms applied to this 
structure have been reviewed by Smith (66). He has defined the peg as 



52 THE PEANUT— THE UNPREDICTABLE LEGUME 

"the young fruit during the stalk-like phases of development which inter- 
vene between syngamy and fruit enlargement." Smith has shown that this 
stalk-likeorgan is^not a gynophore_but in. reality the ovary, elongated by 
the growtli of an intercalary meristem in its base. Jacobs (39) has de- 
scribed the development of this meristem and the differentiation of the 
tissues arising from it. He has shown that the vascular strands extend 
through the meristematic region to the base of the ovarian cavity. The 
loculus of the ovary, distal to meristem in the tip of the peg, contains 
the 2 to 6 ovules. 

The ovary is enclosed by cataphylls of the inflorescence, which in 
turn are covered by the stipules of the subtending leaf. Peg growth be- 
gins immediately after fertilization and the peg usually appears from 
within the enclosing bracts and stipules several days after anthesis. Early 
growth is slow but gradually accelerates until the pegs are elongating very 
rapidly. 

The peg is positively geotropic. Charles Darwin (21) showed in 
1880 that the peg was not negatively phototropic but did respond to the 
force of gravity. The later observations of Badami (3), Jacobs (39), 
Shibuya (65), Theune (71) and Waldron (75) have supported this 
view. The ultimate length of a peg and the time required for it to reach 
the soil is determined by the initial distance from the ground. Pegs in- 
serted more than 15 cm. above the soil surface usually fail to reach the 
ground. In such circumstances, the peg tips usually fail to reach the 
ground. In such circumstances, the peg tips usually die and pod and seed 
development do not occur. Exceptionally, ovule enlargement does occur 
and viable seed develop in aerial pegs, but normal pods are not formed 
( Gregory in Smith, 66) . 

Upon penetrating the soil the peg commonly grows to a depth of 2 
to 7 cm. (but may be covered much deeper than this by cultivation). For 
several centimeters immediately above the soil surface the peg sometimes 
becomes fleshy and much thickened, and loses its green or purple color. 
Its lenticels become enlarged and irregular. Many multicellular hairs may 
be found on the peg surface. Underground the peg may become similarly 
expanded and have copious hairs. The function of these hairs is proble- 
matical. Pettit (50) and Waldron (75) have interpreted the hairs of the 
peg and pod as "root hairs" in structure and function, but Richter (59) 
found their cell walls suberized. He suggested that they anchored the 
peg in the soil. These ha irs are not root hairs but are multicellular 
trichomes characteristic of stems. 



MORPHOLOGY, GENETICS AND BREEDING 53 

Pod 

When the peg reaches its maximum penetration of the soil it loses its 

geotropism and the tip turns to a horizontal position. At the same time 

the pod begins to enlarge and development rapidly ensues. Enlargement 

of the pod proceeds from base to apex (figure 15). Early stages resemble 





Figure IS. — Successive stages in the development of a peanut fruit. Left to right : an 
ovary at time of fertilization ; young aerial peg ; elongated peg after soil pene- 
tration ; the tip of the peg turned to a horizontal position and the beginning of 
pod enlargement; early immature stage of pod development; mature fruit. 
(after Smith, 66.) 

one-seeded pods in appearance. The more rapid development of the basal 
segment is associated with the earlier development of the basal seed. 
When the apical seed aborts, as occurs frequently, enlargement of the 
apical portion proceeds no further. 

At maturity, the shell is usually reticulate and more or less constricted 
between the seeds. According to Thompson (72) and Russell (63) the 
superficial exocarp layers flake oflf during development. The character- 
istic reticulations underlying the veins are ridges of mechanical tissue 
arising as outward extensions of the sclerenchymatous mesocarp layer. 
This layer is continuous except at the sutures. The endocarp consists of 
a parenchymatous tissue which surrounds the ovules during development. 
The cells of the endocarp lose their contents and their walls collapse as 
the pod matures. 

The peanut fruit is a one-loculed, structurally dehiscent, but func- 



54 THE PEANUT— THE UNPREDICTABLE LEGUME 

tionally indehiscent legume. Under pressure the pod tends to split along 
a longitudinal ventral suture. Examining cross sections, Richter (59) ob- 
served that the mechanical tissue of the mesocarp was interrupted along 
this line. He demonstrated that this was the line of normal dehiscence by 
cutting the pod into rings and then passing the rings over suitably sized 
chick peas. The peas were allowed to swell ; the rings were always broken 
along the suture. 

The thickness of the pericarp or shell and the ease with which it may 
be broken open, differ greatly in the different varieties of A. hypogaea. 
The shell may be paper thin or more than 2 mm. thick. There appears 
to be a positive correlation between size of fruit and thickness of shell but 
in segregating progenies of thick-large x thin-small peanuts, thick-small 
and thin-large types occasionally appear. In no case, however, have the 
writers observed thinnest-largest or thickest-smallest combinations. 

The peanut pod varies in size from about 1 x 0.5 to 8 x 2 cm. and 
may contain from 1 to 6 seeds. The seeds are suspended from the inner, 
ventral (upper) surface of the pericarp. The attachment and hence the 
hilum always lies toward the apex of the seed-bearing segment. A limited 
elongation may take place in the isthmus between two seed-bearing seg- 
ments of the pod in some varieties of A. hypogaea. 

Embryo and Seed 

The internal processes leading to the formation of the embryo sac and 
the embryo were first treated by Reed (55) and with somewhat greater 
accuracy by Banerji (4) . Embryo sac development and early embryo and 
endosperm growth have been more recently and fully treated by Smith 
(68). The frequent occurrence of seed failure, commonly observed as 
"pops" and one-seeded pods in cultivated peanuts, led Smith to investi- 
gate the basic reproductive processes which occur in the ovule just before 
and after flowering. 

In the peanut, a single megaspore mother cell in each ovule under- 
goes a normal meiosis and produces four megaspores. The lowest 
(chalazal) spore develops into the 7-celled, 8-nucleate embryo sac, while 
the other spores degenerate. This embryo sac corresponds to the "nor- 
mal type" found in other legumes and found in the majority of the in- 
vestigated cases in flowering plants. By the time of pollination, the 
synergids and antipodal cells have usually degenerated so that the sac con- 
sists of only the egg cell and a large central cell containing the two polar 
nuclei. 

The union of egg and sperm occurs 12 to 16 hours after pollination. 



MORPHOLOGY, GENETICS AND BREEDING 55 

At the same time, the polar nuclei fuses with the second sperm nucleus. 
The primary endosperm nucleus resulting from this triple fusion divides 
first, usually within 8 to 12 hours after fertilization. The zygote has 
usually divided to form a two-celled embryo within 36 hours. 

During the first 10 to 12 days after flowering", growth proceeds slowly 
in both embryo and endosperm, but in this same period the peg, after a 
slow start, grows rapidly and usually approaches or reaches the soil 
surface. From the fifth to the tenth day of fruit development, the growth 
and elongation of the peg accelerate rapidly. During this same period 
cell and nuclear divisions are virtually absent in the embryo and endo- 
sperm (Smith, 68). After the tenth day, both embryo and endospferm 
begin to grow rapidly in normally developing seeds, concurrently with 
the beginning of underground pod enlargement. The durations of the 
early stages of both peg and seed development vary widely as a result 
of position on the plant, competition with other fruits, and other environ- 
mental circumstances. 

More than 93 percent of the eggs have been reported as fertilized 
and about 12 percent of the early embryos as aborting during the first 
two weeks of growth (Smith, 67). As most of the fertilization failures 
or embryo abortions occurred singly in the apical ovules, approximately 
14 percent of the pegs studied contained a single developing seed in the 
basal position. This value is compared with 18 percent one-segmented, 
one-seeded pods which were harvested in the control sample. Failure of 
fertilization and early embryo abortion appear to account for the occur- 
rence of most of the one-seeded fruits so frequently seen. 

It is equally evident from these results that normal megasporogenesis, 
embryo sac development, and fertilization provide no basis for predicting 
the occurrence of the later seed failures which give rise to the shriveled 
seeds and empty pods characteristic of the pop condition. When a young 
seed fails during the peg stage, the portion of the ovary containing it also 
fails to grow. Failures of the seed after underground pod enlargement has 
begun do not seem to inhibit the completion of pod development. Thus, 
recent data (68) are in harmony with the conclusions of Burkhart and 
Collins (15) and of Colwell and Brady (18) that calcium deficiency in 
the fruiting zone of the soil is a principal cause of the "pop" condition. 

Flowering and Fruiting 

Peanut flowers begin to appear 4 to 6 weeks after planting. Richter 
(59) observed that in contrast to flowers of most plants, those of peanuts 
are most abundant on the lower nodes. He considered this an adaptation 



56 



THE PEANUT— THE UNPREDICTABLE LEGUME 



to the geocarpic habit of the plant. He noted that the pegs and mature 
fruits are also concentrated at the lower nodes. In more suitable climates 
than that of Breslau where Richter worked, flowering and peg formation 
occur much farther up the stem than he suspected, flowers appearing 
even at the last visible node. He was essentially correct, however, in say- 
ing that peg production is suppressed at the upper nodes. 

The daily production of flowers during the life of the peanut plant 
has been described by Shibuya (65), Bouffil (13), and Smith (66). 
Bouffil illustrated frequencies of flower production by days for five con- 
secutive seasons. He compared his frequency distributions with the distri- 
bution given by Shibuya for Formosa as well as with a distribution from 
material grown in the neighborhood of Paris. All of his graphs and those 
from Shibuya's data are similar. Smith found also that flower-frequency 
curves obtained during three seasons from North Carolina material 
closely resembled those of Bouffil. Careful records of hours of sunlight 
and amounts of rainfall were available to Bouffil, temperature being vir- 
tually constant in Senegal, and he stated that the pattern of flowering was 
not influenced by meteorological conditions. In the data from the Paris 
area the number of flowers was much reduced but the general pattern was 
not altered. 

Bouffil's analysis of flowering frequency led him to describe four 
stages in the progression of flowering: (1) slow increase, (2) fast in- 
crease, (3) flowering peak, and (4) decline of flowering. Smith described 
the onset of flowering as gradual with flower production beginning to 
accelerate after two to three weeks. Peak production was reached four to 
six weeks after the first flowers appeared, the time depending upon variety ; 
then flowering decreased at approximately the same rates as the increases 
occurred. In a Spanish strain, two-thirds of the flowers were produced 
during a one month period beginning six weeks after planting ; in a Vir- 
ginia runner, four-fifths of the flowers were produced during the third 
month after planting (figure 16) . 

The following fertility coefficients for Bouffil's line 24-11 are based 
on means of 90, 89, and 64 plants, respectively, grown at the M'Bambey 
Station, Senegal. 





Mean flowers 
per plant 


Mean pods 
per plant 


Fertility coeffi- 
cient, flowers/pod 


1940 


599 

751.3 

578 


133 
161.3 
68.8 


4 . 5 (flowers) 

4.65 

8.4 


1941 


1942 





20 



o 



10 



MORPHOLOGY, GENETICS AND BREEDING 



S7 




14 21 28 4 (I IB 25 
JULY AUGUST 


1 6 
SEPTEMBER 


DAILY FLOWER PRODUCTION IN ARACHIS 
1944 SEASON 

RALEIGH, N.C. 





Figure 16. — The seasonal distribution of flower production in a Virginia peanut. 
(after Smith, 67.) 

Gregory's data (26) from artificially pollinated flowers, all flowers 
not used being removed from the plants, showed a fertility coefficient of 
nearly 2, twice as efficient as Bouffil's 1940 and 1941 values and 4 times 
as efficient as his 1942 figure. Smith (67) reported that 63 percent of 
the flowers studied produced pegs and one-third of the pegs developed 
pods, but only 13.5 percent of the original flowers produced mature 
fruits (figure 17). Expressed as flowers per fruit the fertility coefficient 
was 7.5. 

Aerial Flower — Subterranean Fruit 

From the time that the peanut first became known to Europeans, its 
flowering and fruiting habits attracted widespread attention. In spite of 
perennial interest in this botanical curiosity, many misconceptions have 
arisen concerning the structure of its flowers and their relation to nor- 
mal fruiting. Even today one can hear the statement that the yellow 
flowers of peanuts have nothing to do with the production of fruit and 
that there exist peanuts capable of producing 2000 pounds of nuts per 



58 THE PEANUT— THE UNPREDICTABLE LEGUME 

acre without bearing a single yellow flower. Smith (66) has recently 
written a review of the controversy which arose among botanists over 
the manner in which peanuts produce their fruits, and the resulting mis- 
conceptions which still persist. 

The first accurate description of the peanut flower was published by 
Poiteau in 1806 (52). Nevertheless, in 1839, Bentham (10) stated that 
peanuts possessed two kinds of flowers, one of the showy, yellow, flower 

PER CENT 
100.0 OVULES PRODUCED 



93.3 EGGS FERTILIZED 



63.5 OVULES IN PEGS AND PODS 



21.4 OVULES IN ALL PODS 

13.5 OVULES IN MATURE PODS 

11.2 SEEDS, SOIL CALCIUM ADEQUATE 

7.1 SEEDS, SOIL CALCIUM DEFICIENT 



REPRODUCTIVE EFFICIENCY IN ARACHIS HYPOGAEA 



10 VIRGINIA JUMBO RUNNER PLANTS 
5233 FLOWERS, 2 OVULES PER FLOWER 



Figure 17. The production of flower.s, pegs, pods, and seed in a Virginia peanut. 
(after Smith, 67.) 

considered to be sterile ; the other, with neither calyx, corolla, nor sta- 
mens, which produced the fruit. In other words, he not only did not see 
the relationship between the flowers and the fruits, but he also thought 
that the pegs were some kind of peculiar flower. Later Bentham was in- 
volved in a controversy with a gentleman from Georgia named Neisler 
(46) who correctly described the relationship of flowers, pegs, and ma- 
ture fruits in 1855. Meanwhile, in 1853, Poiteau (53) had restated his 
position of 1806. Although Bentham recognized his own error in 1856 
(see Gray, 25) and corrected it (11), Didrichsen (22) in 1866, and 



MORPHOLOGY, GENETICS AND BREEDING 59 

Kurtz (41) in 1875, failed to discover Bentham's retraction and criti- 
cized him severel}'. Other writers have overlooked Bentham's (11) cor- 
rection of his mistake, and one may find his erroneous concept in many 
recent reference works and texts which Smith (66) has cited. The read- 
ers of these usually reliable works of the past 40 years will do well to be- 
ware while perusing the section dealing with Arachis hypogaea. 

VARIABILITY, GENETICS AND BREEDING 
Variability 

In the preceding pages of this chapter we have described in general 
terms the form, structure, and reproductive morphology of peanuts. On 
occasion we have given ranges of size, number, and kinds of some of the 
things described. It should be borne in mind, however, that the detailed 
studies necessary to the descriptive morphology of a plant cannot pos- 
sibly characterize all the plants in a genus, a species, or even a single va- 
riety. It is the common possession of certain basic features, however, 
which leads to the establishment of such taxonomic entities. The confi- 
dence with which we place a group of plants in a single taxonomic cate- 
gory is based on no more than a conceived average of the almost universal 
variability found in any natural group. It is the discovery that this range 
of variation extends beyond the accepted but sometimes ill-defined limits 
which leads to the creation of new varieties, species, genera, or higher 
taxonomic categories. 

The systematic position of the genus Arachis was for a long time a 
moot question. In 1839 Bentham ( 10) first properly associated Arachis 
with Stylosanthes and Chapmannia in the tribe Hedysareae. Taubert (70) 
separated the tribe Hedysareae (which includes such plants as beggar's 
ticks and lespedeza) into six subtribes; the last of these, the Stylos- 
anthineae, includes the peanut and its relatives. This subtribe includes 
only four genera, Zornia, Chapmannia, Stylosanthes, and Arachis. They 
possess in common the following features : 

"Stamens all united into a closed tube; anthers alternately basally* 
and dorsally attached; flowers in terminal or axillary spikes or small 
heads, seldom somewhat raceme-like; leaves pinnate, mostly with few 
leaflets, without stipels." (Taubert, 70. Translated from the German). 
Arachis, Stylosanthes, and Chapmannia form a closely related group, all 
of them possessing the characteristic tubular hypanthium, pinnate leaves, 
and straight embryo. Zornia dififers materially from the rest of the tribe 

* Adnate, introrse in Arachis— author's note. 



60 THE PEANUT— THE UNPREDICTABLE LEGUME 

in not possessing any of these distinctive features. As described by Burk- 
art (14), Hoehne (34), and Taubert (70) Arachis differs chiefly from 
Stylosanthes and Chapmannia in producing pegs, being geocarpic, and in 
producing most of its flowers on the lower nodes of the stem, while 
Stylosanthes and Chapmannia have shorter hypanthia, produce no pegs, 
have aerial fruits, and produce most of their flowers in the upper axils. 

The genus Arachis itself, before 1839, consisted of only one species, 
the cultivated peanut, A. hypogaea. Bentham, however, described five ad- 
ditional species all collected from the wild in South America. Since that 
time several additional species have been described. 

Hoehne (34,35) recognized twelve species in the genus Arachis. 
These, with their subspecies and forms, are listed below : 

A. tuberosa Benth. A. prostrata Benth. 

A. guaranitica Chod. & Hassl. Subspecies: Hagenbeckii (Harms) 

A. Diogoi Hoehne Hoehne 

Form : typica Hoehne A. iimrginata Gardn. 

Form : subglabrata Hoehne Form : submarginata Hoehne 

Form : sericeo-villosa Hoehne A. nambyquarae Hoehne 

Form : submarginata Hoehne A. hypogaea L. 

Fovm-.minor Hoehne Forms: various 

Subspecies: major Hoehne A. glabrata Benth. 

A. angustifolia (Chod. & Hassl.) Killip Form: typica Hoehne 

A. helodes Mart. Form : major Hoehne 

A. villosa Benth. Form : minor Hoehne 

A. villosulicarpa Hoehne 

Varieties of Arachis hypogaea L. 

The dififerent forms of A. hypogaea have stimulated various workers 
to develop varietal classifications of the cultivated peanut. Taxonomists 
frequently resort to controversy concerning species delineation because 
the ultimate nature of organic variation necessarily leads to intergrading 
forms. If the species problem is difficult, the varietal problem becomes 
nearly impossible. Yet as certain species grade into one another, varietal 
clusters tend to assume sufficient distinctness to approximate specific 
rank. Depending on the chance evolutionary time level at which any ob- 
server may happen to approach such clusters, he will find himself con- 
fronted with a continuous array of variability at one extreme or almost 
species-distinct varietal clusters at the other. Cultivated peanut varieties 
appear to fall somewhere between these two extremes, dififerent enough 
to be interesting yet similar enough to be exasperating. 

In his study of the origin of cultivated peanuts, Dubard (23) suggested 
that the forms which were transported from Brazil to the west coast of 



MORPHOLOGY, GENETICS AND BREEDING 61 

Africa were varietally distinct and more primitive than those peanuts of 
Peru which had found their way into Mexico in pre-Columbian times, 
and later travelled from Peru to the islands of the Pacific, East Asia, and 
as far as Madagascar. The latter forms reached Spain via France from 
Mexico. The varietal terms "African" and "Asian" arose from this post- 
Columbian distribution of cultivated peanut forms. There can be little 
question but that the peanut known in the United States as "Valencia" is 
the Peruvian-Mexican- Asian-Spanish (Archbishop of Valence) form. 

ChevaHer (16) noted that the upright and prostrate habits of peanuts 
were insufficient grounds for establishing subspecies. 

Some 40 varieties were listed by Hayes (30) who gave their countries 
of origin. His classification divided A. hypogaea into runner and bunch 
varieties. Four groups of varieties were separated under his bunch group 
on the basis of such characters as corolla color, seedrcoat color, hairiness, 
etc. Six runner groups were similarly separated on the basis of such 
superficial characters. 

John and Seshadri (40) went so far as to give a Latin description of 
a variety "gigantea" which they had discovered among the segregating 
progeny following a cross. 

Hull (36) stated that the peanuts which he used in a genetic study 
fell into three groups, runner, Spanish and Valencia. 

Clos (17) used the following ten characteristics in classifying the 
types of peanuts grown in Argentina: Carriage of the plants, color of 
the seed coats, number of seeds per fruit, size of fruits, constriction of the 
fruits, elevation of fruit venation, color of the stalk, pubescence of the 
stalk, weight of the seeds, and venation of the seeds. Like Hayes, Clos 
divided cultivated peanuts into two main groups, upright and prostrate. 
Then by means of the characters listed above he isolated eleven upright 
types and four prostrate types known in Argentina. 

More recently Boufifil (13) has stated that the only characters which 
are of any value in varietal classification are (1) the carriage of the 
plant, and (2) the presence or absence of a rest period in the seeds. He 
further states that characters ordinarily utilized in the classification of 
plants are of no value in separating varieties of peanuts. He disagrees 
with Chevalier (16) and separates A. hypogaea into two subspecies on 
the basis of whether the plans are prostrate or upright. His classification 
follows : 

A. Plants prostrate 

A. hypogaea subsp. africana 

(a) Early maturity, immediate germination : var. praecox 

(b) Late maturity, delayed germination : var. tarda 



62 THE PEANUT— THE UNPREDICTABLE LEGUME 

AA. Plants erect 

A. hypogaea subsp. asiatica 

(a) var. praecox 

(b) var. tarda 

When a large collection of types of peanuts are brought together, or 
segregating progenies of varietal crosses are observed, one of their out- 
standing features is the fact that any ordinarily accepted agronomic va- 
riety has its own cluster of seed sizes ; seed-coat colors ; shell thicknesses, 
reticulations, and constrictions ; plant types ; leaf colors, textures, 
margins ; and many other characters. 

Before Europeans brought the varieties together and began artificial 
crossing, self-pollination and geographic isolation led, in pre-Columbian 
times, to the formation of rather distinct varietal groups. The authors 
mentioned above, with the exception of Hull, have not produced a satis- 
factory classification nor have they agreed with one another. Everyone 
who has worked with peanuts can recognize the three varieties known 
in the United States as Virginia, Spanish, and Valencia. If the agricul- 
turist can identify these peanut varieties at a glance, there must be some 
obvious morphological features which distinguish them. 

Richter (59) correctly understood the morphology of the peanut in- 
florescence and properly described it, but French, English, and American 
workers have rarely referred to his excellent work. Richter specified in 
clear morphological terms just where the inflorescences are produced, but 
he did not provide illustrations. Cultivated peanuts apparently never pro- 
duce flowers on the main axes of the plant, but on some more or less 
well-developed axillary reproductive branch. The flowers, contrary to 
scientific and popular opinion, never arise from the axils of foliage leaves. 
It is the reproductive branch or inflorescence which thus arises. The in- 
florescences produce scale leaves similar to cataphylls and it is in the 
axils of these that the subsequent branches of the inflorescences bearing 
the flowers are produced. Cataphylls (unless one calls cotyledons cata- 
phylls) do not occur on the main stem axis. 

Virginia peanuts diflfer from Spanish and A^alencia peanuts in seldom, 
if ever, producing an inflorescence from the first cataphyll of a lateral 
branch of any order. This character is common to all forms of Virginia 
peanuts. They may have large, medium, or small seed, and thick, inter- 
mediate, or thin shells. They may be prostrate or upright but in the 
basic features which lead a farmer to say, "Virginia Runner," "Virginia 
Bunch" or "some kind of a Virginia," they are similar and may be dis- 
tinguished from other peanuts. On the other hand, Spanish and Valencia 
peanuts always produce inflorescences in the first cataphylls of secondary 



MORPHOLOGY, GENETICS AND BREEDING 63 

and higher order branches. This fact, in addition to the extreme reduction 
of the first internode of most of the lateral branches, so that in second- 
order branches the first cataphyll may be closely appressed to the main 
stem, leads to the erroneous impression that twin buds occur in the leaf 
axils on the main stem axis. 

A botanical key to the varietal groups of peanuts follows : 

A. Lateral buds of the central axis all vegetative. First cataphyllar node of 
n + 1 order branches vegetative ; second occasionally reproductive.* 

(a) n -|- 2 order branches occur as pairs of vegetative branches alternating 

with pairs of reproductive branches Virginia 

AA. Lateral buds of the central axis vegetative or reproductive. First and second 
cataphyllar nodes of n + 1 order branches reproductive. 

(a) n -)- 2 order branches irregularly reproductive and vegetative. Pods 

two to three seeded Spanish 

(aa) n + 2 order branches all reproductive or sometimes mostly vegeta- 
tive distal to the 6th-8th node, n -f- 3 order branches all reproductive. 
Pods 3-6 seeded Valencia 

* See previous sections. Vegetative Structure of the Mature Plant: Stem; and Reproductive 
Morphology: inflorescence. " 




Figure 18. — An n-\- 1 order, cotyledonary lateral branch of a Virginia runner pea- 
nut. Two n -\- 2 vegetative branches arise from the first two nodes of this 
Isranch, two n + 2 reproductive branches from the next two nodes, two n + 2 
vegetative branches from the next, two n + 2 reproductive from the next . . . 
The same pattern of alternating pairs of nodes appears on each successive order 
(n -\- 2, n-\- 3. n-\- 4) of vegetative branches, so that the occurrence of repro- 
ductive branches does not limit the extent of the branching system. The branch- 
ing order may but usually does not exceed n-\- 4 vegetative and n -\- 5 repro- 
ductive in Virginia runners. 



64 



THE PEANUT— THE UNPREDICTABLE LEGUME 



1. Virginia (figures 18, 19, 20). — Plants copiously branched, con- 
sisting as in Valencia and Spanish of four or more principal lateral 
branches. Laterals frequently far exceeding the main stem in length, 
though of approximately the same length in some erect types. Main stem 
nodes all vegetative. All lateral branches vegetative in the first node and 
mostly vegetative in the second node. Nodes of the lateral branches of all 
orders generally occur in alternating pairs of two vegetative and two re- 
productive. Upper internodes 20-25 mm. in length. The main stem usually 
produces many lateral branches in erect types or few in prostrate types. 
Leaves and leaflet smaller, leaflets more firm and pointed elliptic than in 
the two following; dark, glaucous green. Stems moderate in size less 
coarse than in following, erect or prostrate. Fruits from 2-5 cm. in length 
1-3 seeded, mostly 2 seeded. Shells thick or thin, reticulation usually 
prominent. Constrictions between seeds apparent to marked. Seeds 0.5 
gm.-2.0 gms., elongated and pointed, usually germinating only after 30- 




.i 

Figure 19. — An n + 1 order, cotyledonary lateral branch of a Virginia bunch pea- 
nut. The same succession of two n-\-2 vegetative branches and two n-\-2 re- 
productive branches occurs as is found in Virginia runner. The branching pat- 
tern of the higher order (n + 2, n + 3) vegetatives also consists of alternating 
pairs of vegetative and reproductive branches. As in Virginia runner, the extent 
of the branching order is indeterminate, but in Virginia bunch it usually does 
not exceed n-\- 3 V and n-\-4 R. 



MORPHOLOGY, GENETICS AND BREEDING 65 

360 days "rest" period, usually pink, sometimes tan, rose, wine, red or 
variegated red and white. Moderately resistant to cercospora leaf spot. 

2. Spanish (figures 21, 22). — Plants moderately branched, consisting 
of four or more main lateral branches arising as in Valencia. Main stem 
and laterals usually of approximately equal lengths. Nodes of the main 
stem above the principal laterals vegetative and reproductive; nodes of 
laterals irregularly vegetative and reproductive, usually continuously re- 
productive for as many as six nodes ; frequently, however, vegetative at 
nodes 3 and 4 on the cotyledonary laterals. First two nodes of lateral 
branches reproductive. Inflorescences unbranched. Leaves and leaflets 
similar to Valencia though usually somewhat smaller and paler green. 
Upper internodes 20-30 mm. in length. Stems moderate in size, usually 








Figure 20, — A Virginia bunch peanut in profile. 



66 



THE PEANUT— THE UNPREDICTABLE LEGUME 




SP 

COT LA" 



Figure 21. — ^An n-j- 1 order, cotyledonary lateral branch of a Spanish peanut. The 
n-\-2 vegetative- branches occur , sporadically and the n + 2 reproductive 
branches arise at the remaining nodes. The upper nodes are all reproductive as 
are all the nodes of the » + 2 vegetative branches. This is in contrast to the 
regularly paired situation present in the Virginia variety. As in Valencia, the 
branching system is determinate, ending with the production oi n + 2 Y which 
produce n + 3 R ' - •'- 



MORPHOLOGY, GENETICS AND BREEDING 



67 



smaller than in Valencia, mostly erect, green. Fruits variable in size, 1-3 
cm., usually about 2 cm. ; 1-3 seeded, mostly 2 seeded, clustered near the 
base of the main stem. Shells thin, prominently veined; beak small or 
lacking. Constriction moderate to pronounced. Seeds variable, spherical 
to rounded elliptic, sometimes red or pink, usually flesh, sometimes white, 
0.2 gm.-0.5 gm., germinating immediately upon maturity. Highly sus- 
ceptible to cercospora leaf spot. 

3. Valencia (figures 23, 24). — Plants sparsely branched, consisting 
usually of four (sometimes six) main lateral branches, one from each 
cotyledonary axil and one from each of the first two foliage leaf axils of 
the main stem. Main stem and laterals usually of approximately equal 
lengths. Nodes of the main axis above the principal laterals mostly re- 




I "fsSiS^^- '.m^Jiu "s^ 



Figure 22, — A Spanish peanut in profile. 



68 



THE PEANUT— THE UNPREDICTABLE LEGUME 



productive. Nodes of the n + 1 laterals often continuously reproductive 
for eight or more nodes. Vegetative branches occasional, rarely more 
frequent on the n + 1 laterals and main stem axis. Highest order of vege- 
tative branching, n + 2, frequently only n + 1. First two nodes of lateral 
branches reproductive. Inflorescence sometimes branched. Leaves and 
leaflets large. Upper internodes 30-35 mm. in length. Stems large, laterals 
sometimes 7.5 mm. in diameter, coarse, mostly erect, occasionally lax; 
frequently purple, but sometimes green. Fruits variable in size 2^6 cm. 
long; 1-6 seeded, mostly 3-4 seeded. Shells variable, usually moderately 
thick with only slightly raised venation ; sometimes thin with prominent 
venation and beaked ; constrictions between the seeds slight, occasionally 
more evident. Seeds variable, spherical or elongated, usually red or 
purple-black, sometimes pink or flesh; 0.2 gm.-0.8 gm., usually about 
0.5 gm. ; germinating immediately upon maturity. Highly susceptible to 
cercospora leaf spot. 

Beattie (9) lists the following varieties grown commercially in the 




Figure 23. — An n + 1 order, cotyledonary lateral branch of one form of Valencia. 
The n + 1 branch produces n + 2 reproductives at its lowest nodes, then 
several n + 2 vegetatives, finally the upper nodes produce n-\- 2 reproductives. 
All the nodes of the » -f- 2 vegetatives bear n + 3 reproductives which terminate 
the branching system. 



MORPHOLOGY, GENETICS AND BREEDING 



69 



\kr— 



-#. 



\//- 



Figure 24. — An » + i order, cotyledonary lateral branch of a Valencia form. In this 
form the peanut branching system is reduced to the n order main stem and four 
n -\- 1 order vegetative branches. Two of these arise from the cotyledonary 
node and two from the next two main stem nodes. All further n -\- 1 nodes and 
all n-\-2 nodes bear reproductive branches which terminate this branching 
system. 



70 THE PEANUT— THE UNPREDICTABLE LEGUME 

United States. They are shown here as they could occur if classified by 
the foregoing system. 

1. Virginia Runner — Prostrate 

2. Jumbo Runner — ' ' 

3. N.C. or Wilmington Runner — " — Virginia 

4. African — ' ' 

5. Virginia Bunch — Erect 

6. Spanish — Erect 

7. Improved Spanish — " — Spanish 

8. Small Spanish — ' ' 

9. Tennessee White — ' ' 

10. Tennessee Red — " — Valencia 

11. Valencia — " 

If this scheme of classification based upon the orders and patterns 
of branching were generally employed, the understanding of reported 
experiments, not only in breeding, but in essentially all other types of 
peanut research would be greatly facilitated. Where original varietal dis- 
tinctions have been obliterated through crossing and segregation, the 
parentage and a brief description in the above terms would furnish the 
needed information. Prevot (54) has already indicated the relationship 
between branching habit and the problem of fertilizer treatments with 
peanuts. It is obvious, however, that this relationship could not be the 
same for both Spanish and Virginia peanuts. 

GENETICS AND BREEDING 

The problem of .the improvement of peanuts through selection is not 
a simple one. The peanut is a plant which is, in our experience, for all 
practical purposes 100 percent inbred, difficult to cross, and productive 
of so few seeds per plant that the recovery of improved types in small se- 
gregating populations is rendered highly improbable. Consequently to- 
day's peanut breeder must not only increase the precision of estimating 
genetic differences within segregating populations, but also must over- 
come the sterility barriers between the various species of peanuts, gather 
fundamental biological information on the structure and physiology of the 
peanut and its relatives, and relate these to the problem of improvement 
through selection. 

The reproductive behavior {i.e. self-pollination) of peanuts is such 
that new forms tend to be preserved and isolated from one another. 
Nevertheless there has been hardly a breeder from the time of Van der 



MORPHOLOGY, GENETICS AND BREEDING 71 

Stok (74) to the present, who has not been able to isolate distinct 
strains from within varieties. The 'question of selection within varieties 
as opposed to selection within hybrid populations has claimed the at- 
tention of peanut breeders. Men with long experience have maintained 
that pure lines of peanuts tend to brealc down if selection pressure is re- 
laxed. The instability of the pure lines may have arisen from (1) acci- 
dental seed mixture (2) natural outcrossing, or (3) chromosomal insta- 
bihty. The first possibility need not be discussed. According to Kushman 
and Beattie (42) natural hybridization occurs with low but significant 
frequency. In experiments designed to clarify this point numerous cases 
in which crossing had occurred between Spanish and Valencia peanuts 
were studied. The observed segregation of seed coat colors followed the 
expected pattern. Three years of work demonstrated a small but definite 
amount of natural crossing. Critical experiments of this nature have not 
been conduct4¥e- by other workers so this is the only reliable published ac- 
count. In contrast, the present senior author has observed the consistent 
uniformity of hundreds of Fj and F^ plant progenies. These have included 
many diverse families from experimental crosses grown side by side. If 
further experimental evidence confirms the opinion that pure lines of pea- 
nuts are unstable in the absence of selection pressure, this will be in 
harmony with the known behavior of peanut chromosomes. Husted (38) 
observed multivalent chromosome associations at first meiotic metaphase 
and concluded A. hypogaea was a tetraploid. Mendes (44) confirmed 
this in 1947. The number of chromosomes in cultivated peanuts is 2w = 
40 wliile some of the wild species examined have 2« = 20, observations 
which the writers have also made. The irregularities reported by Husted 
(38) provide ample basis for predicting sporadic segregation from culti- 
vated strains. 

Notwithstanding the fact that peanuts were subjected to genetic study 
by Van der Stok (74) as early as 1910, only limited progress has been 
made in the improvement of peanuts through breeding. With the advent 
of World War I interest in peanuts as a source of vegetable oil stimulated 
peanut-breeding activity. Thus in the United States reports of breeding 
work began to appear about 1918, Beattie, private correspondence) . Al- 
though the U.S. Department of Agriculture continued its efiforts through 
the third decade of this century, active work at the various State experi- 
ment stations did not begin until near its end. Breeding programs have 
been reported as starting in Georgia in 1931, in Florida in 1928, in North 
Carolina in 1929. During these years most of the work in Virginia, North 
Carolina and South Carolina consisted of making individual plant selec- 



72 THE PEANUT— THE UNPREDICTABLE LEGUME 

tions from among existing stocks of peanuts. The programs in both 
Florida and Georgia appear to have developed from selection within 
hybrid populations from varietal crosses. Meanwhile reports from India 
(1), the Philippines (24, 49, 56, 61, 62), the Dutch East Indies ^^12), 
French West Africa ( 16) and elsewhere continued to reach this country. 
Breeding programs have been in existence in the U.S. Department of 
Agriculture for 30 years, in State experiment stations for 20 years, and 
for similar lengths of time in various foreign countries. At present some 
efifort is being expended toward peanut improvement through selection in 
nearly all warm temperate and tropical countries. 

Despite the great effort put forth in various countries of the world 
little success has been achieved in peanut breeding. The products of these 
researches are not, by and large, the plants which fill the commercial 
fields ; or if they are they have not, raised to any degree the average output 
of the areas where released. For example, the average production per acre 
in the Virginia-Carolina area continues at about 1,100 pounds per 
acre, notwithstanding the sporadic "improvement" announcements of the 
past 30 years. During these same years, while the spring wheat industry 
of the United States and Canada was saved by breeding and pathological 
researches, and corn production was revolutionized by breeding, the "im- 
proved" selections of the peanut breeder have continued to maintain the 
low State average yields (figure 25). 

As yet we can only surmise the biological explanation of Bouffil's 
(13) statement that the hybridization of p^eanuts has been attempted but 
that up to the present no positive results have been obtained ; or of Darl- 
ington's (20) declaration, in reviewing Mendes' (44) cytological work, 
that perhaps this will open the way to improved varieties from interspe- 
cific crosses in this plant, which hitherto has been so unresponsive to im- 
provement through the ordinary methods of cross-pollination and selec- 
tion. 

While there is no doubt that peanuts are difficult material, the inde- 
pendent and isolated attempts of the various workers on the problem 
have been a contributing factor to the slow progress made in this field. 
It is misleading to take too seriously the comparison of 30 years' research 
on wheat and corn with the unconnected reports on the peanut over the 
same period. Few cross-references exist in the literature on peanuts, each 
man having gone his independent way. Thus there have resulted needless 
repetitions of effort and the consequent elementary nature of experiments 
evident in all the literature. The combination of the lack of knowledge, or 
the possession of erroneous information on the biological nature of pea- 



MORPHOLOGY, GENETICS AND BREEDING 



7Z 




CORN North Carolina 



PEANUTS Va.N CTenh. 




PEANUTS S.C.,G*.,Fla., 
Ala.. Miss. 



_L_ 



_X- 



_L_ 



\ 



_i_ 



_L_ 



_L_ 



ia-22 20-Z4 22-26 24-28 26-30 28-32 30^4 32-36 34-38 36-40 38-42 40-44 42-46 44-48 

19-23 21-25 23-27 25-29 27-31 29-33 31-35 33-37 35-39 37-41 39-43 41-45 43-47 

MOVING 5-YEAR INTERVAL 



PEANUT YIELD 1918-1948 



MOVING S-YEAR AVERAGE 



Figure 2S. — Thirty years of peanut production in the southeastern United States. 
The light line shows corn production in North Carolina during the same period. 

nuts with the disparate nature of the breeding experiments conducted, is 
sufficient in itself to render success improbable. 

In reporting the published works on peanut breeding and genetics 
we have been unable to .unfold a sequence of events or to build a co- 
ordinated body of knowledge culminating in recent advanced studies 
logically derived from the results of previous experiments. Instead we 
have attempted to preserve the mosaic of unrelated patterns and have 
organized them only to the extent of presenting first, a summary of 
breeding techniques ; second, inheritance studies; third, disease resistance ; 
and fourth, breeding. 

Techniques 

( a ) Cross-pollination 

Badami ( 1 ) made the following observations with respect to the tech- 
nique of crossing 'peanuts : The pollen sacs burst about sunrise on warm 
days, fertilization is completed within 30 hrs,*, flowers droop in 24 



* It is known to occur in 12-16 hrs; see "Reproductive Morphology''- 



74 THE PEANUT— THE UNPREDICTABLE LEGUME 

hours, wither in 48 hours, pegs elongate in 72 hours, visibly so in 4 or 5 
days, and complete development of fruit and seed takes about 60 to 62 
days from fertilization. Badami emasculated the flowers from S p.m. to 
midnight and pollinated them between 6 and 7 a.m. 

According to investigations of Stokes and Hull (69) the stigma is 
buried among dehisced anthers in the tightly closed keel of the mature 
flowers. The flowers are fully opened before dawn, the anthers dehisced. 
The flowers wither the day of anthesis and fertilization does not hasten 
withering. The flowers were emasculated between 10 and 11 p.m. Acci- 
dental pollination was considered unlikely. Thrips were about the only 
visitors in the greenhouse. Pollinations were made between 8 and 10 a.m. 
and were about 50 percent successful. The cross-pollinated flowers were 
labelled by means of a thread attached to the flower and later transferred 
to the peg. Plants were cultured in 4- gallon stone jars and kept pruned 
back. Fruiting inhibited flowering and flowering could be induced by 
removing the fruits. 

Umen (73) used the technique of removing all the flowers from the 
inflorescence except the one to be cross-pollinated. In this manner the 
first flower of an inflorescence could be used, the remainder removed. 
When this is the case the probability of successful development of the 
fruit is greater and the opportunity for mistaken identity of the cross 
, almost eliminated. Emasculation was done with forceps between the 
hours of 2 and 8 p.m. the day before the flowers were to open. Bagging 
the emasculated flowers was found to be unnecessary. The pollinations 
were made early the next day. The plants were grown in pots. 

Patel et al. (48) emasculated the buds between 5 and 6 p.m. The re- 
sult was checked by a hand lens. Pollination was effected between 7 and 
8 a.m. Ten to 30 percent of the pollinations were successful. The flowers 
were not bagged. The plants were grown in large pots. The crosses were 
marked by different colored threads. After 4 to 5 days the thread was 
transferred to the peg. 

(b) Vegetative propagation 

Many things coordinate the forces of -adversity on the would-be 
peanut breeder. Only a few hours are available for emasculation each 
day and these fall at the rather inconvenient time when ordinary men are 
preparing to go to bed. It should be added that each emasculation con- 
sumes several minutes so that the total for an evening's work is rather 
small. Some alleviation of this difficulty is obtained by the propagation 
of peanuts from cuttings. The number of plants grown from each hybrid 
seed can be much increased by use of this technique. Sufficient work 



MORPHOLOGY, GENETICS AND BREEDING 



75 



has now been done with cuttings to permit the employment of F^ testing 
should this seem to be desirable in peanut breeding. Gregory conducted 
replicated F^ trials of peanuts from cuttings in 1945 with sufficient suc- 
cess to show the reliability of this method of propagation. 

The first work recording the use of cuttings as a tool in varietal ex- 
perimentation with peanuts was reported by Guerrero (28) who, on the 
Island of Guam, made the first recorded comparison of yields of nuts and 
forage per acre of peanuts from cuttings and from seed. It is obvious from 
the limited data given that the experimental error was very large. No 
further work has been reported from this source. Rodrigo (61) became 
interested in the use of cuttings as a means of propagation to escape the 
problem of seed deterioration common to the Philippines. His seed 
germination averaged 94.7 percent and 89.7 percent of the cuttings rooted. 
The following table gives some of the comparative figures on developed 
pods, undeveloped pods, and pegs without pods at harvest for three 
different varieties : 



Variety 
Name 


Propagating 
Materials 


Number of: 


Developed 
Pods 


Undeveloped 
Pods 


Stipes 
Without Pods 


Kinorales 

Kinorales 

Lemery 

Lemery 

Valencia 

Valencia 


seed 

cutting 

seed 

cutting 

seed 

cutting 


26.10 ± 1.15 
23.30 ±0.89 
19.20 ± 1.21 
18.00 ±0.96 
23.40 ±0.94 
14.40 ± 0.73 


11.90 ±0.67 
13.90 ±0.64 
10.70 ± 0.92 
8.60 ±0.70 
13.90 ±0.99 
10.10 ± 0.74 


20.40 ± 1.59 
33.10 ± 2.04 
15.00 ± 2.11 
27.00 ± 2.32 
18.30 ±0.94 
13.70 ±0.87 



Rodrigo pursued the problem of yield from cuttings further. Cuttings 
were taken from three varieties when the plants were 2, 3, and 4 months 
old. This experiment was badly hit by ants and drought so that no com- 
parison could be made between seed and cuttings ; of the cuttings, how- 
ever, the 3-month-old plant cuttings gave the highest percentage rooting 
while the 2-month-old plant cuttings gave the greatest production of 
forage and seed. 

Gregory (26) found that rapidly growing plants just prior to flower- 
ing produced highly successful cuttings. It should be noted, however, that 
the total number of cuttings per plant under these circumstances is much 
smaller than from older flowering specimens. 

Harvey and Schultz (29) compared the yields of plants from cuttings 
of main stems and laterals with the yields of plants from seed. It will be 
recalled that the peanut produces a single main stem, primary laterals, 



76 



THE PEANUT— THE UNPREDICTABLE LEGUME 



and other lateral branches. The test was planted in a split plot design 
where the sources of plants were the subplots (main stem, lateral branch, 
or seed) and the three varieties used were the whole plots. No significant 
differences in yield were found between the two sources of cuttings. The 
yields of plants from seed were significantly less than those of plants 
from main stem cuttings but not less than those from lateral branch 
cuttings. The seed were planted the same day the rooted cuttings were 
placed in the field, but the plants from seed may not have been strictly 
comparable in developmental stage to the cuttings. The following table 
shows the results obtained : 

Yields of Peanuts in Pounds /Acre 





Lateral 
branch 


Main 
stem 


Seed 


Average 
for strain 


N. C. Sel. 32 


1,237.8 
1,002.5 
1,127.6 


1,514.4 
1,281.6 
1,026.7 


890.0 
1,173.9 
1,028.1 


1 193 9 


Martin Co. Runner ...... 

Spanish 2B 


1,132.4 
1,101 






Av. for source of plants. . . 


1,122.3 


1,274.6 


1,030.0 





(c) Field plot size 

Beattie et al. (8) concluded after some years' experience that the 
optimum plot size fpr testing varietal differences in peanuts was a single 
100-foot row or five to six 20-foot rows. Robinson et al. (60) investigated 
optimum plot size from uniformity data. Their conclusions, briefly sum- 
marized below, are perhaps the most reliable information to be had on 
this subject. The uniformity data were handled in terms of decreasing co- 
efficients of variation with increasing plot size. The following diagram 
gives the pertinent results : 



MORPHOLOGY, GENETICS AND BREEDING 



77 



Average Coefficients of Variability for Different Plot Dimensions Where 
' Replications Consist of 6 Assumed Varieties. 



16 

15 

14 

13 

12 

11 

10 

9 

8 

7 



a 














— 


.12i 


-1 (Length and number of units per plot) 


— 


.121 


-2 






— 


.25- 


1 






— 




. 121-3 






— 




.371-1 
.25-2 






— 




.50-1 


.37-2 




— 






.25-3 


.37i-3 


1 


|- 


1 1 1 


1 1 


.50-2 

.50- 

1 1 1 1 1 1 


1 


2 


3 4 5 


6 7 


8 9 10 11 12 



Plot Size {Number of 12^-foot single-row units) 

Inheritance Studies 

Van der Stok (74) reported that red testa and light red testa segre- 
gated three dark red to one light red in the Fj. Badami, Hayes, Hull, 
Patel et al., and Stokes and Hull (1, 30, 36, 48, 69) have studied the 
inheritance of various characters in the peanut. Hull (36) summarizes 
the genetic results vi^hich had been published by 1937. His summary fol- 
lows :* 

"1. Red seed dominant to russet or tan (3:1), Van der Stok (74), Badami (2), 
Stokes and Hull (69), Hayes (30). Four colors purple, red, rose, and white, 
with genes Pp.Rdrd, Riri, R2r2, Patel (48). 

2. Prostrate habit dominant to erect, two factors, Badami (2) ; (15:1) Hayes 
(30) ; duplicate genes, Patel, (48). 

3. Chlorophyll ; three factors with triple dominant dark green and triple re- 
cessive albino, Badami (2) ; two genes, Patel (48). 

4. Dark red stem dominant to light red (3:1), Hayes (30). Violet tinge domi- 
nant, appears to be associated with hardiness, Badami (2). Purple stem, dup- 
licate genes, Patel (48). 

5. Long seed dominant to short (15:1), Hayes (30). 

6. Fertile dominant to sterile, complementary (15:1), Hayes (30). 

7. Normal leaf dominant to crinkled leaf, complementary (15:1), Hayes (30). 



* This is quoted exactly except that the present writers have altered the reference numbers so 
that they now correspond to the references cited at the end of this chapter. 



78 THE PEANUT— THE UNPREDICTABLE LEGUME 

8. Leaf rachis presence dominant to absence, complementary (15:1), Hayes 
(30). 

9. No constriction on pods, double dominant, two factors, Badami (2). 

10. Leaflet size intermediate in Fi and wide range in F2, Badami (2). 

11. Large pod dominant to small, three factors, Badami (2). 

12. Pericarp thickness, five factors, thin pericarp linked with pygmy seed, 
Badami (2). 

13. Deep reticulations on pericarp dominant to shallow, at least four factors, 
Badami (2). 

14. Hairy stem dominant to less hairy, Badami (2) ; 3 :1, Patel (48). 

15. Three or many-seeded pods dominant to less than three-seeded, at least three 
factors, Badami (2). 

16. Long growing season dominant to short, Badami (2) ; 3:1, Patel (48). 

17. Early fading flowers dominant to late, Hayes (30). 

18. Deeply colored corolla dominant to light, Hayes (30). 

19. Red color on leaflet vein dominant to its absence, Hayes (30) . 

20. Sine leaf shape dominant to Valencia shape, Hayes (30). 

21. Required rest period of seeds partially dominant to its absence, Stokes and 
Hull (69). 

22. Variegated seed due to rupture of seed coat as found in A. namby quarae 
partially dominant to its absence in A. hypogaea, Stokes and Hull (69). 

23. Sterile dwarf, 15 :1, Patel (48). 

24. Branching over non-branching, 3:1, Patel (48)." 

Hull's own work was chiefly directed toward analyzing the genetic 
behavior of dormancy in peanut seeds. In addition, however, he reported 
the following results on other characters : 

1. In crosses of Spanish and Runner peanuts long by short seeds were intermedi- 
ate in the hybrid. The results indicated that seed shape was largely con- 
trolled by physiological maternal influence rather than by embryo genotype. 

2. Russet seed coat of Runner peanuts dominant to tan in Spanish. 

3. Yellow seedlings from certain crosses behaved as full recessives in a duplicate 
gene complex with green fully dominant. The assignment of genetic formulae 
with respect to this character cuts across some interesting taxonomic lines, 
for Hull states that the following genetic formulae and varietal association 
was indicated from his study of this character: L1L1I2I2 (Spanish) L1I1I2I2 
(Runner group and A. nambyquarae and LiLiL2L2 (Valencia and A. 
Rasteiro*.) 

4. Valencia plant type was found in the progenies of several crosses of Spanish 
X runner. It behaved as a recessive set of duplicate genes where each parent 
carried alternate recessive and dominant pairs. 

5. Male sterile brachytic dwarf appeared in the progeny of Virginia Runner x 
Tennessee Red and behaved as a simple recessive. 

6. The regressions of twenty-two separate characters as dependent variables, and 
rest period of seeds, seed shape, seed coat color, yellow seedlings, and Valencia 
plant type as independent variables were analyzed. No significant regressions 
were found. 

* A. Rasteiro = a form of A. hypogaea. 



MORPHOLOGY, GENETICS AND BREEDING 79 

Hull measured the rest period in peanut seeds in terms of average 
time to emergence with seeds planted as soon as possible after harvest. In 
the Spanish and Valencia groups this time ranged from 9 to 50 days, 
while in the more dormant group which includes runners, A. namby- 
quarae, and A. Rasteiro it ranged from 110 to 210 days. Hull makes the 
additional statement that, "Peanut seeds planted soon after maturity in 
conditions near optimum for germination frequently required rest periods 
ranging up to 2 years before germination." Hull assumed a multigenic 
control of what he called "seed condition necessary to rest" with a normal 
frequency distribution. He supposed that at about the midpoint of the 
range of seed condition the threshold for germination was attained. Such 
a situation would explain the marked skewness to the left of his frequency 
distribution of days from planting to emergence. 

Since the publication of Hull's summary, Higgins (31, 32) has re- 
ported further inheritance studies. He analyzed the genetics of seed coat 
color in peanuts. Three basic colors were recognized: Red, white, and 
flesh. These were further characterized as follows : 

1. Flesh — Base color is a salmon flesh, pale to dark, reddish lilac markings about 
the hilum and along the veins, sometimes spreading. Varieties : Spanish, N.C. 
Runner (African), Virginia Runner, Virginia Bunch. 

2. Red — This color also includes salmon lilac, various purples, and slate violet. 

3. White — Philippine White and Pearl are greenish white to lilac white which 
weathers to yellow white. 

Red X Flesh Flesh x White (Philippine White) 

Fi all Red Fi all Flesh 

F2 3 Red : 1 Flesh F2 IS Flesh : 1 White 

White (Pearl) x Red 

Fi all Red 

Fa 12 Red; 3 Flesh :1 White 

White (Pearl) x White ( Philippine White) 

Fi all Red 

Fo Red, Flesh, and White 

The numbers were too small in the white x white progeny to establish 
the genetic basis with certainty, but the following suggested formulae 
appear to explain the results obtained : 

Pearl RRF1F1F2F2 dididada 

Phil. White rrfifif2f2 D1D1D2D2 

It is obvious that there are at least duplicate factors for flesh, an ad- 
ditional factor which produces red in the presence of both flesh factors, 
and two factors for color development, the absence of either of which 
results in white. 



80 THE PEANUT— THE UNPREDICTABLE LEGUME 

Disease Resistance 

Varietal resistance of peanuts to sclerotium wilt or southern root rot 
has been reported by Reyes (56). From experiments conducted in the 
Philippines Reyes concluded : "Different varieties of peanuts grown in 
an infected field showed varying degrees of infection. Wilting ranging 
from 31.3 to 50.7 per cent of the plants was noted by actual counts. 

"Varieties used in field inoculation tests showed susceptibility to 
peanut wilt in the descending order as follows : (a) Valencia ; (b) Maca- 
pno; (c) Georgia Red; (d) White Improved Spanish; (f). Biit; (g) 
Cagayan No. 1; (h) San Jose No. 3; (i) Vigan Lupog; (j) Tirik; (k) 
Tai-tau; (1) Virginia Jumbo; and (m) Virginia Jumbo (a). The least 
infected varieties were Virginia Jumbo (a), Virginia Jumbo, and Tai-tau 
while Valencia and Macapno were the most seriously infected." 

Bolhuis (12) stated that A. Rasteiro, A. nambyquarae, and Schwarz 
21, a selection from native sources, were highly resistant to the slime, 
disease {Bacterium solanacearum) . Higgins (31) stated that resistance 
to each of the two leaf spotting fungi is inherited separately and suggested 
that a single factor is involved in each case. With respect to resistance to 
Sclerotium rolfsii this author stated that "most of our selections show 
a high degree of resistance." Reyes and Romasanta (57) reported varia- 
tions in susceptibility among 16 different varieties to Cercospora 
personate. The intensity of infection was measured by leaf spot count 
from a duplicated trial. It was suggested that resistance to this disease 
might be attained through breeding. 

Breeding 

In 1910 Van der Stok began the breeding work with peanuts in the 
Netherlands East Indies. In 1938, Bolhuis gave the following as princi- 
pal objectives in the breeding program: high yield, resistance to slime 
disease, erect foliage, large seeds, pods with more than two seeds, pods 
with slight constriction, and early ripening. 

Badami ( 1 ) reported his initial hybridization results with peanuts in 
1922 and in later annual reports from the Mysore Agricultural Depart- 
ment he has indicated the results of subsequent selection. 

Patel et. al. (48) reported in 1936 that a breeding program had been 
been in progress in Madras for about 5 years. Approximately 100 varie- 
ties were grown in the two annual seasons, irrigated (February- June), 
"rain-fed" July- January) . 

The economic importance of peanuts, their world production, and a 



MORPHOLOGY, GENETICS AND BREEDING 81 

short history of their cultivation in the U.S.S.R. were reported by 
Piroznikova (51). A description of the peanut, its types, varieties, and 
various characteristics were included. Extensive data are presented on 
variety trials in various regions of the U.S.S.R, The main aims stated for 
the breeding program for U.S.S.R. are earliness, drought resistance, 
disease resistance, high oil content, high protein content, and a production 
of a plant suitable for mechanical harvesting. 

From Krasnodar, Umen (73) described the necessity of understand- 
ing the floral biology of the peanut. He stated that pure line selection 
started in 1926 had shown hybridization to be the only promising method 
for improvement of the peanut. To quote from the abstracting journal, 
"The method of pure line selection has not yielded very favorable results, 
especially in regard to resistance to Fusarium and hybridization is re- 
garded as essential." 

Selection for improved varieties of peanuts has been attempted in 
French West Africa since 1924. Many criteria for selection have been 
used without success. The morphological character of the pods and the 
weight per 100 seeds are now the principal characters selected. An exten- 
sive series of local strains collected from the native farms is grown at the 
central station. The selections are made but are subsequently increased in 
the locality where the original strain is grown and known to be adapted. 
Hybridization, either natural or artificial has yielded no results of con- 
sequence to the French West African program. Bouffil has not entirely 
abandoned the idea of the use of hybridization in peanut breeding but 
feels that the existing stocks of peanuts in French West Africa must first 
be purified. 

In the United States, prior to 1930, the most extensive work on the 
breeding of peanuts was reported from Florida by Stokes and Hull (69). 
Single plants were selected from within an unselected variety, Florida 
Spanish, seven of which were tested for 8 years. Some showed increases 
over the original variety averaging 22.8 percent. It was concluded that 
plant-to-row selection produced high-yielding strains. No heterosis was 
observed in the various hybrids made. 

Hull and Carver (37) have continued this work, and in 1936 pub- 
lished a summary of their breeding procedures. These workers concluded 
that the desired types could "hardly be obtained except by hybridization. 
... It has also appeared that large numbers of hybrids would be neces- 
sary to provide reasonable chances of obtaining the desirable types." 

In Georgia an extensive breeding program is under way with a col- 
lection of varieties and strains with objectives to combine high yield, 



82 



THE PEANUT— THE UNPREDICTABLE LEGUME 



quality, and oil of Spanish peanuts with disease resistance and nonsprout- 
ing of the bunch and runner types. 

Results of variety yield trials for the years 1929, 1930, and 1931 were 
reported for the Holland, Virginia, Station by Beattie and Batten (7). 
This work was mainly directed toward increasing seed size. It was con- 
cluded that at least seven strains of Virginia type peanuts had inherent 
qualities of extra large seed. 

In 1943, Batten (5) reported regarding the selection work at the 
Virginia Station: "The idea has been to develop a strain which would 
produce a high percentage of extra large kernels, 30 to 32 per ounce." 
The method of breeding has been confined to single hill selection without 
prior hybridization. The breeder stated that these selections behaved as 
pure lines. Batten (6) announced the release of two improved selections 
in 1945. The following table presents comparisons of these strains with 
a local commercial variety : 

A Comparison of Yield and Grade of Two New Strains of Peanuts with a 

Commercial Variety 





Yield per Acre 


Meat 


Extra 
Large 


Kernels 

per 

ounce 


Value 




Un- 
shellei 


Shelled 


per 

acre 




Pounds 


Pounds 


Per cent 


Per cent 


Number 






1945 
2262 
1695 


1323 
1698 
1170 


68.0 
75.0 
69.0 


53 

27 
35 


27 
37 
30 


$182.44 


Holland Virginia Runner. 
Commercial Jumbo 


«223.01 
$157.30 



Beattie, in private correspondence with one of the writers, stated: 
"Peanut Improvement by Selection: All this work has been carried on in 
cooperation with the State experiment stations in South Carolina, Vir- 
ginia and Georgia. Dating back to 1918 and using individual hills as 
starting points, a number of high yielding; desirable quality strains have 
been developed. Spanish 18-38, Improved Spanish 2-B, and several 
strains of the large-seeded Virginia type are examples. Spanish 18-38 in 
particular has attained considerable commercial importance in most parts 
of the peanut-producing area." 

Since 1945 the North Carolina Agricultural Experiment Statio.n has 
been conducting research on the nature and extent of eflfective variation 
in populations from peanut hybrids. These experiments have been de- 
signed to indicate what, if any, breeding opportunities exist following the 
varietal crossing of peanuts. Preliminary results from this work show that 



MORPHOLOGY, GENETICS AND BREEDING 83 

the total genetic variability in segregating populations of peanuts is large 
enough to make possible a selection advance beyond the mean of the 
original population. The prior conclusions of Umen and of Hull and 
Carver regarding the necessity of hybridization for the success of prac- 
tical peanut breeding are fully supported by these data. The contrary con- 
clusion reached by Bouffil suggests, however, that further exploration of 
the problem is justified. 

LITERATURE CITED 

(1) Badami, V. K. 

1922- HYBRIDIZATION WORK ON GROUNDNUT. Mysore (India) Ann. Rpts. 

1932. Agr. Dept. 

(2) 

1928. THESIS (unpubl.) University Library, Cambridge, Eng. (Cited from 
Hunter, H. and Leake, H. M. recent advances in agricultural 
PLANT BREEDING. London, Blakiston. 1933) 

(3) 

1935. BOTANY OF GROUNDNUT. Jour. Mysore Agr. and Exp. Union 14: 188- 

194; 15: 59-70. 

(4) Banerji, I. 

1938. A NOTE ON the EMBRYOLOGY OF THE GROUNDNUT (AracMs hypogaea L.). 
Jour. Bombay Nat. Hist. Soc. 40: 539-543. 

(5) Batten, E. T. 

1943. peanuts grow pleasingly plump. plumper pods are sought in 

BREEDING WORK WITH VALENCIA, SPANISH, VIRGINIA TYPES. Southern 

Seedsman 6:11 and 34. 

(6) 

^ 1945. TWO NEW STRAINS OF VIRGINIA TYPE PEANUTS. Virginia Agr. Expt. Sta. 

BuL 370. 1-14. 

(7) Beattie, J. H. AND Batten, E. T. 

1933. tests of varieties and strains of large-seeded VIRGINIA-TYPE 

PEANUTS. U. S. Dept. of Agr., Circ. No. 272. 
(8) , BoswELL, V. R. AND Batten, E. T. 

1936. PLOT AND PLANT VARIATION IN VIRGINIA PEANUTS. Amer. SoC. Hort. 

Sci., Proc. 34:586-58?), 
(9) Beattie, W. R. 

1924. peanut GROWING for profit. U. S. Dept. of Agr. Farmers Bui. 1127, 
revised. 

(10) Bentham, G. 

1839. on the structure and affinities of AracMs and Voandzeia. Linnean 
Soc, London, Trans. 18:155-162. 

(11) 

1859. papilionaceae. In Martius' Flora Brasiliensis 15 (l):85-88, Tab. 25. 

(12) Bolhuis, G. G. 

1938. de selectie van aardnoten, kedelee en cassave. Verslag van de 26 
ste vergadering der Verseeniging van Proefstation-personeel. (Cited 
from Plant Breeding Abstracts 10:235.) 



84 THE PEANUT— THE UNPREDICTABLE LEGUME 

(13) BOUFFIL, F. 

1947. BIOLOGIE, ficOLOGIE ET sfeECTION DE l'ARACHIDE AU s6n6gAL. Mini- 

st^re de la France d'outre mer. Direction de I'agriculture de I'elevage 
et des forSts. Paris. Bulletin scientifique No. 1:1-112. 

(14) Burkart, Arturo 

1939. ESTUDios sistemXticos sobee las leguminosas-hedisareas de la 
REPtjBLicA ARGENTINA Y REGIONES ADYACENTES. Darwiniana 3:117- 
302, 22 lam.) 

(15) BURKHART, L. AND CoLLINS, E. R. 

1941. MINERAL NUTRIENTS IN PEANUT PLANT GROWTH. Soil Sci. SoC. Amer., 

Proc. 6:272-280. 

(16) Chevalier, Aug. 

1933, monographie de l'arachide. Revue de Bot. Appl. et d'Agr. Tropi- 

1934, cale 13:689-789; 14:565-632, 709-755, 834-864; 16:673-871. 
1936. 

(17) Clos, Enrique C. 

1939. LOS Tipos de mani {Arachis hypogaea) cultivados en la Argentina y 
su distribuci6n geogrXfica. Physis 18:317-329. 

(18) Colwell, W. E. and Brady, N. C. 

1945. THE effect of calcium on yield and quality of large-seeded type 
PEANUTS. Jour. Amer. Soc. Agron. 37:413-428. 

(19) COMPTON, R. H. 

1912. AN INVESTIGATION OF THE SEEDLING STRUCTURE IN THE LEGUMINOSAE. 

Linnean Soc, London Jour. (Botany) 41:1-122. 

(20) Darlington, C, D. 

1948. GROUNDNUT BREEDING. Nature 162:621. 

(21) Darwin, Charles. 

1880. the poaver OF movement in plants. New York, D. Appleton Co. 1897. 

(22) Didrichsen, F. 

1866. NOGET OM den saakaldte JORDN0D, Arockis hypogaea L. Botanisk' 
Tidsskrift (Kj0benhavn) 1:5-11 Tab. 1. 

(23) DuBARD, Marcel. 

1906. DE l'origine de l'arachide. Museum National d'histoire Naturelle. 
Paris. Bui. 5:340-344. 

(24) Galang, F. G. and Paulino, P. L. 

1925. A progress report on the peanut varieties at lamao exp. sta., 
lamao, bataan. Philip. Agr. Review 18:261-273. 

(25) Gray, Asa. 

1856. the flowers of the pea-nut (Arachis hypogaea L.). Amer. Jour, of 
Sci. and Arts. Sen 2, 22:435-436. 

(26) Gregory, W. C. 

1945. research and farming. 68th Ann. Rpt. N. C. Agr. Expt. Sta. p. 33-35. 

(27) 

1946. research and farming. 69th Ann. Rpt. N. C. Agr. Expt. Sta. p. 42-44. 

(28) Guerrero, Joaquin. 

1923. report of the assistant in agronomy and horticulture. Guam 
Agr. Expt. Sta. Rpt., 1921. p. 16. 

(29) Harvey, P. H. and Schultz, E. F. 

1943. multiplying peanut hybrids by vegetative propagation. Jour. 
Amer. Soc. Agron. 35:637-639. 



MORPHOLOGY, GENETICS AND BREEDING 85 

(30) Hayes, R. T. 

1933. the classification of groundnut varieties with a preliminary 

NOTE ON THE INHERITANCE OF SOME CHARACTERS. Trop. Agr. WcSt 

Indies 10:318-327. 

(31) HiGGiNS, B. B. 

1938. PEANUT BREEDING. Proc. 39th Ann. Con. Asso. South. Agr. Workers, 
Atlanta, Ga. pp. 57-58. 

(32) 



1940. INHERITANCE OF SEED-COAT COLOR IN PEANUTS. Jour. Agr. ReS. 61: 

745-752. 

(33) , HoLLEY, K. T., Pickett, T. A. and Wheeler, C. D. 

1941. 1. PEANUT BREEDING AND CHARACTERISTICS OF SOME NEW STRAINS. 

Ga. Agr. Expt. Sta. Bui. 213. pp. 3-11. 

(34) HOEHNE, F. C. 

1940. leguminosas-papilionadas. ofiNERo: ARACHis. Flora Brasflica 25, 

II; 122:20 p., 15 Tab. Sec. da Agr., Ind. e Com. de Sao Paulo, Brasil. 

(35) 



1944. DUAS NOVAS ESPficIES DE LEGUMINOSAS DO BRASIL. Arq. de Bot. do 
Estado de Sao Paulo. 2:15-18, 2 Tab. (Cited from Mendes, 1947.) 

(36) Hull, F. H. 

1937. inheritance of rest period of seeds and certain other charac- 
TERS IN THE PEANUT. Fla. Agr. Expt. Sta. Tech. Bui. 314. 46 p. 

(37) AND Carver, W. A. 

1936. PEANUT IMPROVEMENT. Agron. Circ. No. 150 (Mimeographed) Fla. 
Agr. Expt. Sta. The reader should also consult the Annual Reports 
of the Florida Agr. Expt. Sta. 

(38) HusTED, L. 

1936. cytological studies on THE PEANUT, AracMs. 11. chromosome num- 
ber, MORPHOLOGY AND BEHAVIOR, AND THEIR APPLICATION TO THE 
problem OF THE ORIGIN OF THE CULTIVATED FORMS. Cytologia 7: 

396-423. 

(39) JACOBS, W. P. 

1947. THE DEVELOPMENT OF THE GYNOPHORE OF THE PEANUT PLANT, ArachtS 

hypogaea L. 1. the distribution of mitoses, the region of great- 
est ELONGATION, AND THE MAINTENANCE OF VASCULAR CONTINUITY 
IN THE INTERCALARY MERISTEM. Amer. Jour. Bot. 34:361-370. 

(40) John, C. M. and<Seshadri, C. R. 

1936. a new groundnut Arachis hypogaea linn. var. Gigantea patel and 
NARAYANAN (VAR. Nova). Cur. Sci. 4:737-738. 

(41) Kurtz, F. 

1875. ueber Arachis hypogaea L. Botanischer Verein der Provinz Branden- 
burg, Verhandlungen und den Sitzungsberichten, 17: Sitzung 22, 
42-56. 

(42) KusHMAN, L. J. AND Beattie, J. H. 

1946. natural hybridization in peanuts. Jour. Amer. Soc. Agron. 38: 
755-756. 

(43) Marggraf, Georg. 

1648. georgi marcgravi . . . historia rerum naturalium brasiliae. 1. p. 
37 Mundubi. In Piso, W. et Marggraf, G. historia naturalis 
brasiliae. Batavorum, Hackium; et Amstelodami, L. Elzevirios. 



86 THE PEANUT— THE UNPREDICTABLE LEGUME 

(44) Mendes, a. J. T. 

1947. ESTUDOS ciTOLoGicos NO G^NERO Arachis. Bragantia 1 -.HI -261. 

(45) MoNARDES, Nicholas 

1569. JOYFULL NEWES OUT OF THE NEWE FOUNDE WORLDE . . . TranS by J. 

Frampton. London, Wm. Norton, 1577. Reprinted. London, Con- 
stable and Co., 1925. V. 2. p. 14. 

(46) Neisler, Hugh M. 

1855. OBSERVATIONS ON THE FRUCTIFICATION OF THE AracMs Jiypogaea L. 
Amer. Jour of Sci. and Arts. Ser. 2, 19:212-213. 

(47) OVIEDO Y Vald^s, G. F. de 

1535. la historia general de la india. Sevilla, conpriuilegio imperial, 
Lib. 7: cap. 5. p. 74, Del mani. 

(48) Patel, J. S., John, C. M. and Seshadri, C. R. 

1936. THE inheritance of characters in the groundnut Arachis hypogaea. 
Ind. Acad. Sci. Proc. 3 (B):214-233. 

(49) Paulino, P. L. 

1930. preliminary study on peanut varieties at the lamao experiment 
STATION, LAMAO, BATAAN. Philip. Jour. of Agr. 1:273-286. 

(50) Pettit, a. S. 

1895. Arachis hypogaea L. Mem. Torrey Bot. Club. 4:275-296. 

(51) PiROZNIKOVA, M. F. 

1936. (arachis in the u.s.s.r. — from the data of the state trials for 
1929-35). Lenin Acad. Agr. Sci. Inst. PI. Breed., Leningrad, p. 72. 
(Cited from Plant Breeding Abstracts 8:75.) 

(52) Poiteau, M. 

1806. observations sur L'Arachis hypogaea. Academie des Sciences, Paris. 
Memoires presentes a I'lnstitut des sciences, lettres et arts, par 
divers savants . . . Sciences mathematiques et physiques. 1" Serie, 
T. 1 (1806):45S-462. 

(53) • 



1853. note sur VArachis hypogea. Annales des Sciences Naturelles, Paris, 
ser. 3, Botanique. 19:268-272. 

(54) Prevot, Pierre. 

1949. croissance et d6veloppement de l'arachide. Oleagineux, 4:1-11. 

(55) Reed, E. L. 

1924. anatomy, embryology, and ecology of Arachis hypogaea. Bot. 
Gazette 78:289-310. , 

(56) Reyes, G. M. 

1937. sclerotium wilt of peanut with special reference to varietal 
resistance. Philip. Jour. Agr. 8:245-284"; 

(57) AND Romasanta, R. 

1940. varietal susceptibility of peanuts to black spot {Cercospora 
personata (b. & c.) ell. and ev.) Philip. Jour. Agr. 11:371-381. 

(58) Richard, Achille. 

1823. BOTANIQUE M^DICALE, OU HISTOIRE NATURELLE ET m6dICALE . . . Paris, 

Bechet Jeune v. 2 :547-549. 

(59) Richter, Curt Georg. 

1899. beitrage zur biologie von Arachis hypogaea. Inaug.-Diss. Kgl. 
botanisch. Garten zu Breslau. Breslau, A. Schreiber, 1899. 39 p. 



MORPHOLOGY, GENETICS AND BREEDING 87 

(60) Robinson, H. F., Rigney, J. A. and Harvey, P. H. 

1948. INVESTIGATIONS IN PEANUT PLOT TECHNIQUE. N. C. Agr. Expt. Sta. 

Tech. Bui. No. 86. 19 p. 

(61) RODRIGO, P. A. 

1927. GROWING PEANUTS FROM CUTTINGS. Philip. Agriculturist 16:13-18. 

(62) 

1929. YIELDING POWER OF PEANUTS FROM CUTTINGS OF DIFFERENT AGES. 

Philip. Agriculturist 17:519-526. 

(63) Russell, M. W. 

1931. ETUDE ORGANOG^NIQUE DU FRUIT DE l'ARACHIDE. Revue de Bot. Appl. 

et d'Agr. Tropicale 11:885-890. 

(64) SCHMIDEL, ULRICH. 

1567. HISTOIRE VERITABLE D'UN VOYAGE CURIEUX, . . . PAR LE BR^SIL, ET LE 

RIO DE LA PLATA . . . (French edition, Paris, A. Bertrand, 1837. 
p. 136). 

(65) Shibuya, T. 

1935. morphological and physiological studies on the fructification 
OF PEANUT (Arachis hypogaea L.). Taihoku Imperial Univ., Fac. Sci. 
and Agr., Memoirs 17: 120 p. 

(66) Smith, Ben W. 

1950. Arachis hypogaea. aerial flower and subterranean fruit. Amer. 
Jour. Bot. 37: (in press). 

(67) 

(In press). Arachis hypogaea. reproductive efficiency. 

(68) 

(unpublished). Arachis hypogaea. megasporogenesis, embryo sac develop- 
ment, syngamy, and early embryogeny. 

(69) Sto'kes, W. E. and Hull, F. H. 

1930. peanut breeding. Jour. Amer. Soc. of Agron. 22:1004-1019. 

(70) Taubert, p. 

1894. leguminosae. In Engler, A. and Prantl, K. Die naturlichen Pflanzen- 
familien III Teil, Abt. 3:70-388 (Arachis p. 322, 324-S). 

(71) Theune, Erich 

1916. beitrage zui^ biologie einiger geokarper pflanzen. Beitrage Biol. 
Pflanz. F. Cohn 13:285-346. 

(72) Thompson, J. M. 

1929. studies in advancing sterility, iv. the legume. Univ. of Liverpool. 
Publ. Hartley Bot. Lab. 6:1-47. 

(73) Umen, D. p. 

1933. (what has been done in groundnut breeding), (technique of 
ARTIFICIAL hybridization IN Arachis). (biology of peanut 
flowering). Lenin Acad. Agr. Sci., Inst. Sci. Res. Oil Cult. Kras- 
nodar, No. 5:8-12, 29-33; No. 6:1-57. (Cited from Plant Breeding 
Abstracts. 5:60.) 

(74) Van der Stok, J. E. 

1910. onderzoekingen omtrent, Arachis hypogaea L. (katang-tanah). 
Med. van het Dept. Land. 12:176-221. (Cited from Hull, 1937). 



88 THE PEANUT— THE UNPREDICTABLE LECUME 

(75) Waldron, R. a. 

1919. THE PEANUT (AracMs hypogaea) — ijs history, histology, physiology, 
AND UTILITY. Penn. Univ. Bot. Lab. Contrib. 4:301-338. 

(76) Yarbrough, J. A. 

1949. Arachis hypogaea. the seedling, its cotyledons, hypocotyl and 

ROOTS. Amer. Jour. Bot. 36:758-772. 

(77) ■ 

1950. Arachis hypogaea. seedling growth rate. Amer. Jour. Bot. 37:(in 

press) . 



CHAPTER IV 

PHYSIOLOGY and' MINERAL 
NUTRITION 

By 
■' HENRY C. HARRIS AND ROGER W. BLEDSOE^ 

The subject of this chapter is so broad in scope and so detailed that its 
treatment necessitates a Hmited discussion of any particular topic. In a 
limited space the authors have attempted to cover most contributions, al- 
though some foreign publications are inaccessible (23, 24, 25) and un- 
doubtedly others have been omitted unavoidably since the data are pre- 
sented in many languages. 

Various aspects of plant physiology have advanced considerably in 
recent years, yet the application of that knowledge to the solution of 
problems associated with the peanut plant has been much neglected and 
little organized work has been done. After reviewing the work, the 
writers have the impression that greater clarity and new information 
might be gained by applying more precise methods in planning experi- 
ments and in evaluating experimental results. Some authors do not in- 
clude enough experimental data to enable others to repeat experiments 
described. Frequently contributions deal with questions of local im- 
portance. Other papers merely emphasize the inconsistencies of yields 
from fertilizer trials without attempts to explain why such occurred. Some 
problems, namely, the absorption of ions by the gynophore or developing 
fruit and the necessity of such for fructification, have received consider- 
able attention in recent years. To some extent, agreement has been 
reached on the essentials of that problem. Many phases of physiology of 
the peanut plant have been omitted due to the absence of published data ; 
other phases are discussed briefly since they are assumed to be similar to 
that of most plants as given in general references (41, 50, 56, 60). 

'^ Henry C. Harris and Roger W. Bledsoe are agronomists, Florida Agricultural Experiment 
Station. 

89 



90 



THE PEANUT— THE UNPREDICTABLE LEGUME 



GENERAL CHARACTERISTICS 
Foliage 

The peanut is a low-growing, annual, herbaceous, leguminous plant 
with one upright central stem (63, 68, 88) and numerous lateral branches, 
the lower of which may branch several times. The varieties are fairly 
well separated into the bunch and runner types. Lateral branches of 
bunch peanuts are more or less upright, while those of the runner type 
tend to be more prostrate. The central stem is usually taller in the more 
erect varieties. The leaves are compound, pinnate, consisting of two 
pairs of nearly equal leaflets, on a slender petiole of moderate length. 
The leaflets show nyctitropic movement and tend to orient themselves 
so as to intercept the greatest amount of light. So far as the writers 
know, measurements of the total leaf area of peanuts have not been made ; 
however, the area would appear to be relatively large and well suited to 
photosynthetic activity. The leaves are moderately pubescent, which 
should aid in the retention of dust and sprays. During the latter part of 
the growing season there is often a progressive defoliation of leaves from 
the base toward the stem tip. While such defoliation might be associated 
with disease or nutritional deficiencies, there is a natural tendency for 
loss of leaves accompanying plant maturity. 

The rate of leaf and flower appearance as recorded by Mohammad, 
et al. (58), is shown in table 1. 

Maximum increase of leaf and flower appearance occurred with the 
bunch peanuts (Japan and Spanish) during the interim of 56 to 97 
days after planting and from 70 to 125 days after planting with the runner 



Table 1. — ^Average Increase in Number of Leaves and Flowers per 
During Different Periods of Growth. 


Plant 


Variety 


Organ 


Average fortnightly increase in number of leaves and flowers 
per plant between 42 and 154 days after seeding 


42- 
55 


56- 
69 


TO- 
SS 


84- 
97 


98- 
111 


112- 
125 


126- 
139 


140- 
154 


Small 
Japan 


Leaves 
Flowers 


19 
9 


51 
39 


99 
103 


87 
96 


37 
91 


16 
28 




2 






Small 
Spanish 


Leaves 
Flowers 


IS 
12 


76 

75 


92 
192 


71 
175 


27 
118 


10 

55 




15 






Burmese 


Leaves 
Flowers 


17 
3 


76 

37 


80 
80 


98 

154 


64 
233 


44 
136 


32 
73 


26 
32 



PHYSIOLOGY AND MINERAL NUTRITION 91 

type (Burmese). The fresh weight of the green shoots at 140 days was 
about 96 percent of the whole plant. Others ( 10) have found a similar 
relationship. 

Flower, Gynophore and Fruit 

The fruiting parts of the peanut plant have been of special interest 
to a number of investigators (10, 37, 45, 63, 68, 74, 81, 88, 90, 91). 
Botanists have known for more than a hundred years that the flowers 
were of one kind and complete, and yet the idea still persists, according 
to the literature, that peanuts produce two kinds of flowers. Flowers are 
borne in the leaf axils and one or more may appear in the same axil. 
They appear first at approximately 50 days after seeding and then daily 
throughout the flowering period. The orange-yellow flowers are fully 
open in early morning and usually begin to wither and die by noon of the 
same day. Therefore, an accurate record of flower production may be 
obtained. 

Shibuya (74) found the length of the flowering period to range from 
69 to 93 days with the bunch type. That period was 74 days in one experi- 
ment with the runner peanut. Maximum flower production occurred 50 
to 60 days after the first flowers appeared. The bunch peanut produced 
approximately 600 flowers; the runner, approximately 1,000. However, 
there was considerable variation between individual plants. 

Some data of flower production by the Dixie Runner peanut at the 
Florida Station (10) are given in table 2. Plants produced an average of 
644 flowers during a period of about 80 days when grown in sand culture 
with the complete nutrient solution applied to both rooting and fruiting 
zones (table 2) . An unbalanced nutrient supply had a pronounced effect 
on flower production, and blossoming virtually ceased when the root 
treatment of the plants was changed from a complete nutrient solution 
to distilled water. The results shown in tables 1 and 2 and others obtained 
by Shibuya (74) indicate that the runner peanut has more flowers than 
the bunch and that the flowering period ranges from 2 to 3 months or 
longer. 

The gynophore or peg is usually noticeable within 7 days after the 
flower is fertilized. It is formed by division and elongation of cells back of 
the ovaries. The organ is geotropic and by elongation it transfers the 
ovaries from an aerial to a hypogeal position. Elongation generally ceases 
after the gynophore has penetrated the soil to a depth of approximately 
2 inches. Then rapid embryo development usually starts within 10 days, 
and the fruit is mature at about 60 days after the appearance of the flower. 



92 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 2. — Mean Flowers per Peanut Plant (Variety Dixie Runner) as 
Affected by Nutrient Treatment. Roots of Plants Grown in Complete 
Solutions to July 1 (80 Days) and Deficient Solutions to August 20 (SO Days) . 





Flower 


production per 


10-day 


interval 


Mean 


Mean 


Nutrient treatment 


after deficient solutions applied — 


total 


total 




July 1 to August 20 (50 days) 


flowers 


flowers 












July 1- 


during 
















Root 


Fruit 


July 


July 


July 


Aug. 


Aug. 


Aug. 


period 


Zone 


Zone 


10 


20 


30 


9 


19 


20 


of 
growth 


Complete 


Complete 


109 


84 


100 


87 


96 


476 


644 


Complete 


Dist. H2O 


114 


92 


104 


94 


18S 


589 


758 


Dist. H2O ^ 


Complete 


44 


2 


9 


17 


14 


86 


250 


-K* 


Complete 


100 


83 


78 


SO 


IS 


326 


481 


-P 


Complete 


81 


81 


91 


47 


24 


324 


475 


-Mg 


Complete 


107 


109 


112 


60 


5S 


443 


583 


-Ca 


Complete 


lis 


78 


46 


2 





241 


392 


-S 


Complete 


64 


S2 


61 


61 


59 


297 


423 


— Micro- 


















nutrients 


Complete 


54 


64 


33 


IS 


17 


183 


324 


L.s.d. 5% 














179 
246 


164 


L.s.d. 1%.. 














225 



*The negative sign indicates tiie element was omitted from the nutrient solution. 

When the gynophore fails to contact the soil, its length rarely exceeds 
6 inches, and then it eventually withers. The above-ground portion of the 
peg has a stem-like anatomy, while the underground portion has a root- 
like behavior and numerous epidermal outgrowths may be present (fig- 
ure 1 ) . The young fruit is fleshy in nature and the shell of the fruit some- 
times has root-hair-like formations (81, 88, 90, 91). These characteristics 
of the fruiting organ suggest that it might absorb water and nutrients." jj; 




Courtesy Florida Agricultural Experiment Station 

Figure 1. — Gynophore with root-hair-Hke outgrowths. 



PHYSIOLOGY AND MINERAL NUTRITION 



93 



A high percentage of the flowers produce pegs. Shibuya reported that 
about 70 percent of the flowers of bunch peanuts and 75 percent 
of those of the runner peanuts produced pegs, while with the Dixie 
Runner variety 58.7 percent of the flowers produced pegs when plants 
were grown in sand culture (10). 

Shibuya reported that 23 percent of the flowers of the bunch type and 
9 percent of flowers of the runner type produced fruit (mature and im- 
mature) with an average of 45 fruits per plant for each type. Results at 
the Florida Experiment Station (10) show that 9.2 percent of total 
flowers resulted in fruit formation, while 24.4 percent of the pegs which 
entered the fruiting medium produced fruit when plants were grown in 
sand culture. In a similar experiment 17 percent of the gynophores of 
runner peanuts grown in a complete nutrient solution (37) produced 
fruit. Individual plants varied considerably, but the percentage of flowers 
effective in producing fruits was small. The nutrient supply of the plant 
(10, 37) influenced the effectiveness of the flowers and pegs in the pro- 
duction of fruits (figures 2, 3). Calcium, particularly when deficient in 
the pegging zone, gave a low percentage of fruit (figure 4) . 




Courtesy Florida Agricultural Experiment Station 



Figure 2. — Dixie Runner peanut plant which received a complete nutrient solution in 
both the rooting and fruiting zone. 



94 THE PEANUT— THE UNPREDICTABLE LEGUME 




Courtesy Florida Agricultural Experiment Station 

Figure 3. — Dixie Runner peanut plant which received a complete nutrient solution 
in the rooting zone and distilled water in the fruiting zone. 

The peanut fruit may have one, two or more seed. It has been stated 
(4) that with fruit of those varieties which normally produce two seeds 
7 percent of the ovules fail to be pollinated and that an additional 10 per- 
cent of the ovules abort during the early growth period, resulting in about 
17 percent of the fruit being one-seeded. 

The majority of mature fruit are located usually on the basal portion 
of the lowest branches, and results of Middleton and Harvey (55) in- 
dicate that there is a tendency for immature fruit and "pops" (fruits with 
aborted embryoes) to occur farther out on the branches. 

Roots 

The peanut plant has a well-developed tap-root system, similar to 
that of beans or peas, with numerous lateral branches extending a con- 
siderable distance in the soil. Several workers (17, 58, 63, 68, 88,) have 
made a careful study of the root system. The soft, fleshy, fragile roots col- 
lapse and dry quickly when removed from the soil. This tends to give the 
impression that the root system of the peanut is relatively small. 



PHYSIOLOGY AND MINERAL NUTRITION 95 




Courtesy Florida Agricultural Experiment Station 

Figure 4. — Dixie Runner peanut plant which received a complete nutrient solution 
in the rooting zone and a calcium-deficient solution in the fruiting zone (Plant 
not grown same season as the ones in Figures 2 and 3). 

Bruner (17) studied root development of the peanut at different 
stages of development when the plants were grown in a sandy loam soil 
in Oklahoma. When the soil was removed carefully with little disturbance 
of roots it was observed that the tap root of mature plants had a length 
of about 3 feet and that 4 or more rows of lateral roots grew horizontally" 
for several inches and then downward for a distance of 2 or more feet. 
In general, branch roots were perpendicular to the main roots. Numerous 
temporary roots, designated as absorbing rootlets, were present on all 
roots of the permanent system. Such rootlets either deteriorated with 
age or developed into permanent roots. All young branch roots were 
considered absorptive rootlets. During early stages of plant growth the 
absorbing rootlets developed prominently in the first foot of soil, but 
later the subsoil became progressively more and more filled with them. 

In India (58) a similar experiment was conducted using Burmese, a 
runner type, and Small Japan and Small Spanish, bunch types, with 
results shown in table 3. These data indicate that the extensive root 
system of the peanut might penetrate the soil to a depth of 6 feet. 



96 THE PEANUT— THE UNPREDICTABLE LEGUME 

Table 3. — Root Development (Penetration in Soil and Spread) in Centimeters 



Variety 


Age in 
days 


Penetra- 
tion 


Spread 


Age in 
days 


Penetra- 
tion 


Spread 


Small Japan 

Small Spanish .... 

Burmese 

Small Japan 

Small Spanish. . . . 
Burmese . 


18 

18 

18 

110 

110 

110 


66 

60 

42 

136 

ISO 

192 


31 
41 
47 

132 
87 

112 


140 
140 
140 


130 
150 
190 


105 

80 

113 







It would be difficult to arrive at the relative weights of roots and 
plant shoots since, because of their fragile nature, many roots are lost 
when removed from the soil. Mohammad et al. (58), reported the green 
weight of roots of plants 18 days old to be 75.4, 84.5 and 49.5 percent of 
the green-shoot weight for Small Japan, Small Spanish and Burmese 
varieties, respectively. At 140 days these values were 3.8, 2.6 and 3.3 
percent, respectively. The proportion of roots to shoots gradually de- 
creased with increasing age. Complete recovery of all roots to depths of 
5 and 6 feet, as these workers attempted, would be difficult, which prob- 
ably accounts for the low values obtained for older plants. Bledsoe and 
Harris (10) found that when peanuts were grown in sand culture for 
130 days, the average green weight of the roots of plants was 13.4 percent 
of the green weight of the tops. The collective information indicates that 
the root system of the peanut is much more extensive than is generally 
realized. 

Adventitious roots sometimes develop on lateral branches of runner- 
type peanuts when in contact with the soil during humid conditions (37, 
58) . This has been given little attention but it is probable that such roots 
occur only on the more recumbent types under favorable moisture and 
weather conditions. However, at times, these roots might be effective in 
absorbing nutrients, and, if so, would increase the area of the absorptive 
system of the peanut. 

Root Hairs 

The majority of papers reviewed state that few if any root hairs occur 
on the root of the peanut plant. Pettit (63) failed to find root hairs while 
Waldron (88) found hairs in limited numbers as rosettes at the base of 
lateral branches and at tips of vigorously growing roots of young plants. 
Plants in larger containers with less air drainage did not produce tip 
hairs. Reed (68) observed few rosettes of hairs and no root-tip hairs on 
field-grown plants. Mohammad et al. (58), found root hairs on peanuts 



PHYSIOLOGY AND MINERAL NUTRITION 97 

grown in containers, but not when grown under field conditions. Failure 
to find hairs on the latter was thought to result from washing them ofif in 
the excavation process. It has been reported (3) that the epidermis of 
the roots of peanuts in the seedling stage sloughs ofif and typical root 
hairs are not produced, although peculiar tufts of hairs form at the base 
of most of the branch roots. Conversely, Bruner (17) indicated that root 
hairs were plentiful on the absorbing rootlets of the field plants he 
studied. Since the roots of peanuts are fragile, it is possible that the root 
hairs in many cases may have been lost in the harvesting process. If, 
however, peanuts have very few root hairs, as many believe, the major 
portion of root absorption would be through channels other than root 
hairs. 

In summary, the plant has an extensive root system, the branches 
sometimes have adventitious roots, the gynophores produce root-hair-like 
outgrowths, and the fruit develops in the soil and sometimes has forma- 
tions similar to root hairs on the shell. Nutrients could be absorbed by 
each of these organs. 

WATER AND OXYGEN RELATION 

The peanut is classified as a mesophytic plant but has xerophytic 
tendencies since it grows well in areas of Texas (68) and other States 
which may be considered as a transition zone between the mesophytic east 
and the xerophytic western plains. 

Peanuts are usually grown on well-drained soils which are frequently 
sandy in nature. This ecological relationship suggests that liberal amounts 
of oxygen might be beneficial and that excessive moisture is not desirable 
for best development of peanuts. Shibuya (74) indicated that oxygen in 
the pegging area is necessary for fruit production, but the amount re- 
quired was not determined. However, data relative to drought resistance, 
water and oxygen requirements of the peanut plant are not available so 
far as the writers are aware. 

It is usually assumed that water enters plants largely through the 
root hairs. If peanuts have few root hairs, then water absorption would 
have to be by other means. As stated previously, adventitious roots, 
root-like hairs on pegs and sometimes on shells of fruit, may be present, 
but the relationship of those structures to water absorption has not been 
established. However, it has been shown that pegs and developing fruit 
do absorb some mineral elements (9, 19, 84). It is assumed that water 
movement through the peanut plant would be similar to that of most 
other plants. 



98 THE PEANUT— THE UNPREDICTABLE LEGUME 

LIGHT AND TEMPERATURE RELATIONS 

Peanuts do not appear to be especially sensitive to length of day. 
The plant seems to grow very well from the tropics to the middle tem- 
perate zone. The day length in most of that area could be classified as 
intermediate, which suggests that such is satisfactory for peanut growth. 
In the United States peanuts are usually planted in April or May and 
maximum fruit development probably occurs during July and August 
when the days have begun to shorten. There is little seasonal variation in 
day length in southern India, and peanuts are sometimes planted in the 
fall in which case maximum fruit development occurs in the spring when 
days are lengthening. 

Moore (59) found that Spanish peanuts bloomed abundantly when 
illuminated continuously for several weeks. Cheliadinora (21, 22) found 
that longer days increased the green weight and flower production, al- 
though the latter was not consistent. However, the ratio of fertilized to 
unfertilized flowers was higher with the short-day plants. Shaded plants, 
especially those on the shorter photoperiods, had fewer undeveloped pods 
and gynophores, which was attributed to earlier flowering when a more 
favorable lime and nutrient supply was available to aid development of 
fruit which had set. These results indicate the length of day has an effect 
on the peanut ; however, critical studies of the photoperiodic response are 
lacking. 

Although the intensity of light would seem to be important, few data 
have been published in reference to its connection with peanuts. Moore 
(59) found that when shaded plants were grown with 3- or 4-hour 
periods of daylight, blooming was practically prevented because of in- 
duced carbohydrate starvation, while Cheliadinora (21) produced good 
yields under partial shade. Those results indicate that slight shading is 
not particularly harmful as is a pronounced shortage of light. 

Peanuts grown in an air-conditioned greenhouse at California Insti- 
tute of Technology^ required a high day temperature for normal develop- 
ment. Cool temperatures resulted in chlorosis and poor development. 
Similar results have been observed at the Florida Station. These obser- 
vations seem to be in agreement with the results of Cheliadinora (22) 
that the photoperiodic treatment is effective only when the temperature is 
favorable during the flowering period. An increase in temperature also in- 
cteaied the yield of fruit (22), which agrees with the general assump- 
tion that the peanut is a warm-weather crop. 

^ Personal correspondence, W. P. Jacobs. Princeton University. 



PHYSIOLOGY AND MINERAL NUTRITION 99 

PHOTOSYNTHESIS. CARBOHYDRATE 
AND NITROGEN METABOLISM 

It is assumed that photosynthesis and the carbohydrate and nitrogen 
metabolism of the peanut are similar to that of other plants and a general 
discussion of these topics may be omitted. However, it seems desirable to 
mention the work of Moore (59) regarding the carbohydrate-nitrogen 
balance in the metabolism of the peanut because of its possible importance 
in relation to yields of field-grown plants. Moore produced plants with 
various carbon/nitrogen ratios by altering the light and nitrogen supply. 
High-nitrogen plants were succulent, dark blue-green in color, with 
slender stems. High-carbohydrate plants were firm in texture, light in 
color, with thick stems. Both types were weakly vegetative and non- 
fruitful. Plants with a carbon/nitrogen ratio intermediate of the extremes 
gave satisfactory yields. However, it was pointed out that the fruiting 
tendency of the peanut was less sensitive to a change in the carbon/nitro- 
gen ratio than that of the tomato plant. Results given in other papers 
(10, 18, 37) suggest that the carbon/nitrogen ratio as affected by nu- 
trient supply has considerable influence on flower and fruit production. It 
is possible that many of the conflicting results in peanut experimenta- 
tion would be explainable if such interrelations were better understood. 

GROWTH-PROMOTING SUBSTANCES 

Hormones or growth-promoting substances have not been used ex- 
tensively on peanuts. Shibuya (73) reported that P-indole acetic acid in 
lanolin, (proportion of 1 to 10), hastened germination when applied to 
the scratched testa of seed of freshly harvested peanuts. He also reported 
(75) that the number of flowers per plant was increased when sprouted 
seed were soaked Yz and 2 hours, and unsprouted seed soaked 24 hours 
in a water solution of 0.02 percent of that compound. A lanolin prepara- 
tion of the hormone applied to sprouted seed hastened flowering and in- 
creased the number of flowers. 

Naphthalene acetic acid and five commercial hormone preparations 
were used with field-grown Spanish peanuts at the Alabama Station ( 1 ) . 
The former and possibly one or two of the latter compounds slightly 
increased nut production. However, there seemed to be little advantage in 
their use and in some cases nodulation was depressed. Best results oc- 
curred when the compounds were used in association with seed 
inoculation. 



100 THE PEANUT— THE UNPREDICTABLE LEGUME 

Liu and Lou^ were unsuccessful in stimulating the ovule into seed 
development by means of a variety of substances, including auxins, vita- 
mins and different plant extracts. Long immersion of the gynophore in 
0.02 percent naphthalene acetic acid caused roots to develop just above 
the undeveloped ovary. These workers were able to initiate fruit develop- 
ment by grafting gynophore tips to detached cotyledons and culturing 
them until the food supply of the cotyledons was exhausted. 

Jacobs* indicates that the auxin which diffuses out of excised tips of 
gynophores exhibits polarity of transport, that is, moves only from ovary 
end toward the proximal end of the gynophore. 

DORMANCY AND GERMINATION 

Hull and Stokes (44, 81) reported dormancy of the peanut seed to 
be hereditary in nature and that the rest period of some seed might be 
as long as 2 years. The rest period of seed of the Spanish and Valencia 
types ranges from 9 to 50 days, while that of some runner types might 
range from 110 to 210 days. Seed of the Spanish types will germinate 
in the field unless harvested promptly after maturation. The longer 
rest requirement of the runner type is desirable if peanuts are left in 
the field to be "hogged off" during the fall or winter months. However, 
difficulties in germination of the runner peanut are rarely encountered 
since the rest requirement is satisfied in the interval between fall harvest- 
ing and spring planting. Hull (44) reported that the time required for 
breaking the rest period of Florida Runner and Spanish seed was in- 
creased when stored at 3° C. and decreased when stored at 20° to 40° C. 
A regular practice was followed of storing seed at 30° C. for 30 days after 
harvest, when quick germination was desired. The data indicate that the 
rest requirement of the peanut seed decreased as storage temperature 
increased from 3° to 40° C. which is opposite of that required by seed of 
many crops. 

Results by Beattie et al. (7) indicate that winter storage tempera- 
tures of 32°, 40° and 70° F. had no significant effect on germination of 
several varieties of seed tested. Unshelled, stored seed seemed to germin- 
ate somewhat better than those shelled. Additional experiments to de- 
termine the effect of age on germination were conducted with Valencia 
and Improved Spanish varieties. When held at a storage temperature of 
approximately 70° F. there was favorable germination of Valencia pea- 
nuts for 5 years and of Spanish for 3 years, after which there was a dis- 

' Personal correspondence, Dr. P. S. Tang, dean. College of Agriculture, National Tsing Hua 
University, Peiping, China. 

* Personal correspondence, W. P. Jacobs. 



PHYSIOLOGY AND MINERAL NUTRITION 101 

tinct loss in germination. Pons et al. (65) stored peanuts at minus 18° C, 
1° C. and 27° C. for 4 years. Those stored at 27° C. were not viable, 
while those stored at lower temperatures germinated perfectly. In view of 
these results it appears that the viability of peanut seed may be good for 
from 3 to 5 years, depending upon the variety and the temperature of 
storage. 

The viability of seed is usually determined by a germination test. Re- 
cently Brewer (16) reported good agreement between the tetrazolium 
chloride chemical test and germinability by an ordinary method. If a 
chemical method for determining the viability of peanut seed could be 
perfected, it might be of considerable advantage to persons involved 
in germination studies. 

ABSORPTION OF MINERAL ELEMENTS 

Mineral elements considered essential for plant growth, with minor 
exceptions, are absorbed by the roots from the soil. It is generally assumed 
that plant roots absorb ions either from the soil solution or by a root- 
colloid exchange. 

Cations such as calcium, magnesium, potassium, sodium and hydro- 
gen are sorbed by the soil colloids. Through the phenomenon of base ex- 
change the cations are liberated to the soil solution and thus become 
available for intake by the roots. For example, carbon dioxide resulting 
from root respiration or from the decomposition of organic matter can 
react with the soil water to form carbonic acid. The hydrogen ions from 
the carbonic acid may displace cations attached to the soil colloids. The 
cations released to the soil solution as the result of ionic exchange can 
then be absorbed by the plant. The base exchange reaction is reversible 
and the amount of cations present in the soil solution at any time will 
depend on several factors. Jenny and Overstreet (46) contend that by a 
root-colloid exchange mechanism there can be a direct exchange of 
ions between the root and the soil colloid. According to this theory, ions 
sorbed on colloids may be as readily available to plants as ions free in 
solution. 

The plant absorbs anions from the soil solution. Anions, with the 
possible exception of the phosphate ion, are not retained in any appreci- 
able quantities in well-drained soils and unless used by crops are usually 
leached out of the soil rather rapidly. The water-soluble phosphate com- 
pounds are thought to be precipitated in the soil as insoluble or relatively 
insoluble compounds which largely prevent their leaching. The supply 
of soil phosphorus available to the plant depends on a series of complex 



102 THE PEANUT— THE UNPREDICTABLE LEGUME 

reactions which are not entirely understood. Two other important ele- 
ments, nitrogen and sulfur, often occur in the soil in the form of organic 
matter and are released to the soil solution as a result of decomposition. 

The above discussion is only an indication of some of the factors in- 
volved in supplying nutrients to the absorbing areas of plant roots. The 
concentration of anions and cations of the soil solution is usually in- 
creased by the addition of fertilizers, cover crops, lime and farm ma- 
nures, as well as by nitrogen fixation by organisms and the removal of 
sulfur and nitrogen from the atmosphere by rain water. 

The absorption and accumulation of ions by plant roots is a compli- 
cated process involving internal factors such as transpiration, respiration, 
photosynthesis and other metabolic activities associated with growth. 
Aeration, moisture, temperature and other environmental conditions sur- 
rounding the roots are also known to influence absorption. 

The absorption of ions by roots of the peanut plant is assumed to be no 
different from that by other plants. However, since the fruit of the peanut 
develops in the soil, its relation to ion absorption has been given con- 
siderable attention. Several investigators (63, 68, 74, 88) suggested the 
possibility of water and nutrient intake by the gynophore. Van der Volk 
(85) observed that a soil extract aided fruit development, while Burk- 
hart and Collins ( 19) were the first to demonstrate that an element, lith- 
ium, was absorbed by the gynophore and distributed within the plant. 
The latter workers also reported fruit quality to be benefited by the pres- 
ence of calcium in the fruiting medium. Brady et al. (13, IS) demon- 
strated that fruit filling was significantly increased when a single calcium 
salt was added to the fruiting medium, while Harris (37) found fruit de- 
velopment to be negligible when a calcium-deficient nutrient solution was 
applied to that medium. It was reported {2i7) that yields were increased 
when the sulfate ion was used in the fruiting medium, while Brady et al. 
(15) failed to get a favorable response from that ion. It has been shown 
also that nitrogen ^^* (84), phosphorus ^^*, and radioactive cobalt (37) 
are absorbed in small quantities by the developing fruit and translocated 
to other parts of the plant. Bledsoe et al. (9) found calcium*^* to be 
actively absorbed by the shells and seed of developing fruit with some 
s^^movement to other parts of the plant when the labeled calcium was ap- 
plied to the fruiting medium. Conversely, when calcium *°* was applied 
tolthe roots of the plant, a small quantity of the labeled calcium was 
found in the shell, but never more than a trace could be detected in the 
seed of developing fruit. 

* Small number refers to atomic weight. 



PHYSIOLOGY AND MINERAL NUTRITION 103 

FUNCTION OF NUTRIENTS AND DEFICIENCY 
SYMPTOMS 

The nutrients as a group are thought to have a number of general 
roles, but in most cases it is difficult to state the exact function of a given 
element. A deficiency of any essential element adversely afifects plant 
growth and yields. Mineral-deficiency symptoms are rarely found with the 
peanut when grown under field conditions but have been observed with 
plants grown in nutrient solution. Burkhart and Collins (19) described, 
deficiency symptoms of the Virginia Bunch peanut in the young stage, 
while other workers (10, 37) have described the efifects of a deficiency 
of the major elements for the Dixie Runner peanut at a later stage of 
growth. However, the symptoms described are, at best, roughly qualita- 
tive and in many instances are not specific. The role of nutrients in 
peanuts is assumed to be similar to that of other plants and is discussed 
briefly in connection with observed nutrient-deficiency symptoms. 

Nitrogen. This element is the main constituent of protoplasm and 
occurs in a number of other organic compounds, one of the most im- 
portant being chlorophyll. One of the main functions of nitrogen is 
obviously its requirement for the formation of new protoplasm in growth. 
Large amounts of nitrogen usually cause peanut plants to become dark 
green in color, grow rapidly, producing succulent vegetation that does 
not flower and fruit well (58). A lack of nitrogen in the peanut plant re- 
sults in stunted growth, yellow foliage, reddish coloration of stems, and 
few nodules are found on the roots ( 19) . 

Phosphorus. Young meristematic tissue contains considerable phos- 
phorus where it is utilized in the growing region in the formation of 
nucleoproteins and a number of other phosphorus compounds, including 
important respiratory enzymes and intermediates. Without phosphorus 
nuclear division and meristematic activity is decreased. Considerable 
quantities are stored in fruit and seed, hence the yield and size of seed 
may be afifected. This element hastens ipaturity and root development. 
Peanuts with a low phosphorus content have a small leaf surface. The 
leaves are a dull bluish green in color, and in later stages they become 
yellowish and drop. 

Potassium. Potassium occurs largely in the plant as soluble organic 
and inorganic salts. It is transported from the older parts to the actively 
growing regions of the plant under conditions of potassium deficiency. 
The exact function of potassium is obscure, but it is thought to play a part 
in the formation and translocation of various carbohydrates, the utili- 



104 THE PEANUT— THE UNPREDICTABLE LEGUME 

zation of nitrogen, and in cell division. Potassium-deficient peanut plants 
(10, 37) have few necrotic "scorch" areas at the leaf margins. In the late 
stages of potasium deficiency the stems near the tips of branches become 
reddish in color, then brown, which is followed by death of the tissue. 

Calcium. Most of the calcium of plants occurs in the foliage and very 
little is found in the seed. The peanut seed is especially low in this ele- 
ment. Calcium-oxalate crystals are sometimes found in plant tissue. 
Calcium is considered relatively immobile in plants. Root growth of the 
peanut is severely affected by a shortage of calcium. A deficiency causes 
stunting and small distorted leaves near the tips of the branches. Inter- 
veinal brown pitted areas which coalesce to form larger necrotic spots 
develop on the affected leaves which give the leaves a bronze color. Basal 
stem cracks and die-back of the affected shoots occur during later stages. 
A deficiency of calcium (27) also affects the fill and quality of peanut 
fruit. 

Magnesium. The chlorophyll molecule contains magnesium, and since 
a deficiency of this element results in chlorosis, it plays a part in photo- 
synthesis. Although only a small proportion of the magnesium of the 
leaf can be accounted for by that in the chlorophyll, a large proportion of 
this element is carried in the green foliage, and there is a considerable 
amount in the seed. Magnesium leaf deficiency symptoms of the peanut 
(19) appear first as a chlorosis of margins of older leaves. In later stages 
the leaf margins may become orange in color. Magnesium has been 
demonstrated to be a factor in fruit production (10, 77, 78). 

Sulfur. Sulfur is well distributed in the plant in the form of proteins, 
volatile compounds, and sulphates. Sulfur is not a part of the chlorophyll 
molecule. However, it may be required in the process of chlorophyll 
formation, since deficient plants have a pale green color. It seems to af- 
fect root development and to have an important part in respiration pro- 
cesses and cell division. The writers grew peanuts on a minus sulfur 
nutrient solution and the plants were smaller, but no other visible de- 
ficiency symptoms appeared. Burkhart and Collins (19) indicate that a 
deficiency of sulfur caused the leaves to be a lighter green color. 

Iron. Plants grown on soils of high pH values frequently show 
iron-deficiency symptoms because of its unavailability. Iron is not a part 
of the chlorophyll molecule, and yet a deficiency results in chlorosis. It is 
assumed to have a catalytic effect in oxidation-reduction processes within 
cells, and it is found in enzymes. The quantity of iron present itl plants is 
very small and it is quite immobile. Typical iron chlorosis developed 
when peanuts were grown in Hoagland's and Arnon's nutrient solution 



PHYSIOLOGY AND MINERAL NUTRITION 



105 




Courtesy Florida Agricultural Experiment Station 

Figure 5— Dixie Runner peanuts showing the effect of 10 pounds per acre of copper 

chloride applied to Arredonda loamy fine sand before seeding. Right, complete 

fertilizer, including microelements ; left, complete fertilizer, only copper omitted. 




Courtesy Florida Agricultural Experiment Station 

Figure 6. — Foliage of G. F. A. Spanish peanuts grown on soil treated before seeding 
with a complete fertilizer and all microelements, except copper. Note the extreme 
copper deficiency symptoms. The few yellowish-white spots are associated with 
the deficiency, but the relationship of the dark leaf spots has not been in- 
vestigated. 



106 THE PEANUT— THE UNPREDICTABLE LEGUME 

(42) by the drip-culture method (76). The deficiency was corrected 
quickly by spraying iron on the plants. 

Boron. A deficiency of boron affects the growing tissues, similar to 
that of calcium, resulting in death or growth abnormalities. The mobility 
of calcium is related to the boron supply. A boron deficiency for peanuts 
(19) resembles a calcium deficiency except that the necrotic areas are 
localized near the leaf margins. : i , 

Manganese. Manganese is in some way related to chlorophyll produc- 
tion since a deficiency results in a chlorosis of J)lants. It seems to play a 
|)art in oxidation and reduction processes possibly through its effect on 
enzymes. Shear and Batten (71) reported that when peanuts were grown 
on heavily limed soils the foliage was chlorotic and yields were reduced 
due to the unavailability of the manganese. 

Copper and Zinc. A deficiency of copper results in chlorosis, prevents 
nitrogen from functioning normally (32, 35), and reduces yields. Harris 
reported that in copper deficiency the bud area of the peanut was affected, 
the terminal leaflets were chlorotic, small and distorted, a few yellowish- 
white spots appeared on many leaves, and the yields were greatly reduced 
(figures 5, 6) . The pattern was much the same as that reported by Allison 
et al. (2) when peanuts were grown on soils in the Everglades and was 
similar to that attributed to thrip injury by Shear and Miller (72) and 
to leaf hopper injury by Metcalf (53). It is quite possible that such char- 
acteristics are similar to those resulting from insect injury. However, the 
symptoms described above did not occur when copper was applied to the 
soil before peanuts were planted. 

Zinc-deficiency symptoms of the peanut have not been described, 
although some workers (2, 6) have reported that applications of zinc 
have increased yields. 

Molybdenum. Molybdenum is considered an essential element for 
some plants (82, 86). The foliage of the peanut plant had a dark green 
color when a small amount of molybdenum was applied to the soil, and 
shoot growth was increased by its addition to nutrient solutions (37). 

CHEMICAL COMPOSITION 

The data of mineral analyses of various parts of peanut plants as 
compiled from several sources (26, 33, 43, 48, 83) are given in tables 
4 and 5. Few values for sulfur were found, and it would appear that the 
evaluation of this element would merit more attention. The results given 
in these tables merely indicate the mineral content of plants when grown 
under various conditions. Therefore, caution should be used in drawing 



PHYSIOLOGY AND MINERAL NUTRITION 



107 



s 

o 
o . 



e m 



s- Q 



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to 'M es 


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108 



THE PEANUT— THE UNPREDICTABLE LEGUME 



conclusions about the differences in mineral composition, because there 
are practically no comparative analyses of different types of plants when 
grown under controlled or known conditions. 

Seed 

The mineral composition of mature seed of peanuts is relatively con- 
stant for a given variety. The nitrogen (protein) content of seed of the 
Spanish type is reported (79) to be higher than that of the Virginia pea- 
nut. However, while the data ( 5, 30, 33, 43, 91 ) of nitrogen content as 
well as that of other elements indicate varietal differences, it is not known 
whether such differences are significant. Data of mineral composition of 
seed as compiled from several sources (26, 33, 43, 48, 83) are given in 
tables 4 and 5. 



Table 5.- 



-Range in Percentage of Inorganic Constituents in the Peanut 
Kernel, After Hoffpauir et al. (33, 43) 



Potassium . 
Calcium. . . 
Magnesium 
Phosphorus 
Sulfur 



.68-. 89 
.02-. 08 
.09-. 34 
.25-. 66 
.19-. 24 



Zinc 

Manganese. . 

Iron 

Copper 

Boron 

Molybdenum 



.0017-. 08 
.0008-. OS 
.0018-. 10 
.0007-. 03 
.0026-. OS 
.0008-. 003 



Hoffpauir and Guthrie (43) report that 87 percent of the nitrogen 
of the peanut seed is present as arachin and conarachin. Their data indi- 
cate that the amino acids usually considered essential for animal growth 
are present in the seed. 

The average percent oil content of seed of control treatments from 
results of Middleton et al. (54) are as follows: 48.5, 49.1, 50.1 and 51.8 
for Virginia Bunch, North Carolina Bunch, Spanish 2B, and White 
Spanish, respectively. Others (30, 43, 91) have reported results indicat- 
ing some varietal differences in oil content. Several workers (30, 54, 62, 
74) have shown that the oil content of mature seed is much higher than 
that of shrivels and immature seed. Those data suggest that an accurate 
description of seed samples should be included when oil analyses are 
reported. 

The composition of oil from Spanish seed (33, 43) is given in table 6. 

Peanut oil is nondrying, edible, and has a specific gravity of 0.917- 
0.920, refractive index of 1.467-1.470, saponification number of 186- 
194, and iodine number of 85-100 (33, 43, 93). 

There is little change in the firee fatty acid content or iodine number 



PHYSIOLOGY AND MINERAL NUTRITION 
Table 6. — Oil from Spanish Peanuts 



109 



Glycerides Percent 

Oleic 52.9 

Linoleic 24. 7 

Palmitic 8.2 

Stearic 6.2 

Arachidic 4.0 

Lignoceric 3.1 

Unsaponiiiable material . . 0.2 

Total 99.3 



of the oil of unshelled peanuts when stored in closed cans at 1° C. for 2 
years (80). Oil of seed stored at 27° C. for 4 years (65) is much less 
stable than that of seed stored at 1° C. or at minus 18° C. for the same 
period. The oil of immature seed (62) has a higher free fatty acid content 
than that of mature seed. 

Peanut seed is an excellent source of the B vitamins (33, 40, 43, 64) 
but contains only small quantities of the A, C and D vitamins. The ap- 
proximate range in values of vitamin content as microgram of vitamin per 
gram of seed is as follows: riboflavin 1.05-1.57, thiamin 8.5-14, nicotinic 
acid 88-200, niacin 144-158, pantothenic acid 25, pyridoxin 3, biotin 0.34, 
inositol 1800, and folic acid 2.8. A considerable quantity of vitamin E is 
also present. Heat above about 150° C. decreases the vitamin content (29, 
40) . Fertilization of the soil is reported to have had no effect on the Bj 
content of peanuts (67) but there were large varietal differences. 

Values of some of the organic constitutents of the peanut seed as 
compiled from the results of Fraps (30) are given in table 7. Similar 
values have been published by others (40, 43). Results by Burkhart 
(18), Jodidi (47) and Moore (59) show that t*he organic cornposition 
of peanut seed can be influenced by environmental factors which affect the 
growing plant, but the data are too limited for generalization. The litera- 
ture offers little information on the organic composition of the seed dur- 



TabU 7 


. — Range in Percentage of Carbohydrates and Other Components of 
THE Peanut Kernel 


Mois- 
ture 


Pro- 
tein 


Ether 
extract 


Crude 
fiber 


N-Free 
extract 


Ash 


Reduc- 
ing 
sugars 


Disac- 
charide 
sugar 


Starch 


Pento- 
sans 


7.42 
4.00 


35.25 
24.10 


54.15 
40.85 


4.26 
2.06 


21.20 
6.02 


3.05 
1.'82 


0.28 
0.06 


5.21 
2.31 


3.18 
0.94 


2.72 
2.20 



no 



THE PEANUT— THE UNPREDICTABLE LEGUME 



ing its development. As stated previously, mature seed have a higher oil 
content than immature seed. Very immature seed are quite high in free 
fatty acids (62) which decrease to a low level at maturity. Gallup and 
Staten (31) report an increase of protein and oil and a decrease of crude 
fiber and nitrogen-free extract of seed with shells during the last 5-week 
period of development. 

Analysis (43) of the skin or testa of seed shows it to be high in fiber 
and ash and to contain appreciable amounts of fat and nitrogenous ma- 
terials. 



Shells 

The mineral composition of shells is given in table 4. The mineral 
content of seed is little affected by fertilization, whereas that of the shell 
(28, 51, 52) has been used as an index of the calcium supply available to 
the developing fruit. Indications are that at least four factors affect the 
mineral composition of shells, namely (a) development of seed, (b) 
nature of the soil colloids, (c) calcium and other nutrients supplied the 
peanut, and (d) the length of tifne the fruit remains in the soil. Empty or 
poorly filled shells (28) have a higher nitrogen, potassium and magnesium 
content than the shells with well-developed seed, while the calcium con- 
tent of the shell is not consistently affected by seed development. The 
peanut fruit seems to be able to obtain more calcium (51, 52) from some 
types of soil colloids than from others with the same degree of calcium 
saturation. Moreover, the application of calcium to the soil where peanuts 
are grown increases the calcium content of the hulls (28). Results by 
Bledsoe and Harris ( 10) indicate that the shell of the fruit absorbs very 
small amounts of magnesium arid phosphorus from the medium in which 
it develops but actively absorbs calcium (9) and possibly potassium. The 
writers have observed also that the potassium content of shells of peanuts 
which cling to the vines when harvested is much higher than that of shells 
of peanuts removed ff6m the soil after harvest. 

The approximate organic composition of peanut hulls as compiled 
from the results of Fraps (30) is given in table 8. Little work has been 



Table 8.- 


—Approximate Composition of Peanut Hulls, 
(percentage — dry basis) 


Frotein 


7.31 

1.19 

65.73 

21.22 

4.53 


Reducing Sugars 

Disaccharide sugars 

Starch 


59 


Ether extract 


1 72 


Cpu(le fiber 


74 


N-free extract 


Pentosans, . . 


17 82 


Ash 











PHYSIOLOGY AND MINERAL NUTRITION HI 

done on factors which influence the organic content of shells. However, 
Moore (59) reported that shells of peanuts grown on a high nitrogen 
solution had a slightly higher ether extract and nitrogen content than 
those grown on a very low nitrogen solution. 

Gynophores 

A deficiency of any of the macro-elements (10) gives a low content 
of the particular element in the young gynophores. Furthermore, a de- 
ficiency of calcium or magnesium seems to cause the potassium content 
to be higher, and conversely. Apparently the level of nitrogen (59) in 
the nutrient solution influences the amount of the various carbohydrates 
in this organ. 

Roots 

The data of Killinger et al. (48) do not indicate any consistent strik- 
ing differences in the mineral coinposition of the roots of plants which had 
received various fertilizer and sulfur-dusting treatments. However, there 
seemed to be a gradual decrease in content of some elements of roots when 
harvested at different dates after planting (table 4) . The results of Moore 
(59) indicate that a high nitrogen content in the nutrient solution de- 
creases the starch, sugars and other carbohydrates of the roots. 

Foliage 

The mineral composition of the foliage of peanuts is quite variable 
as shown in table 4. Some of the variation is probably due to variety dif- 
ferences, but few comparisons have been made of, varieties grown under 
the same conditions. Values of peanut hay reported by Collins and Morris 
(26) diiifer from the values for the more mature hay given in this table. 

Data of table 4 indicate that the mineral composition of the foliage is 
affected by maturity. This is further substantiated by the results of 
Burkhart and Page (20) who sampled leaf blades 2, 3 and 5 months after 
planting and found that the average concentration of calcium, magnesium, 
phosphate and sulfate increased with maturity, while the potassium con- 
tent decreased from the first to second sampling, but increased from the 
second to the third sampling. Other results (20, 61) show that different 
parts of the foliage vary in mineral composition. Calcium seemed to be 
highest in the middle and lower leaves, potassium and phosphate in 
young tissue, magnesium in the more mature tissue, and sulfates in the 
lower portions of the plant, especially the lower petioles and stems. 

Results by Bledsoe and Harris (10) indicate that the nutrient supply 



112 THE PEANUT— THE UNPREDICTABLE LEGUME 

to the roots has a pronounced effect on the mineral composition of the 
foliage. A deficiency of any major nutrient element to the root zone re- 
sulted in low values of that element in the leaves. A deficiency of potas- 
sium gave high calcium and magnesium values of the leaves, and a de- 
ficiency of either calcium or magnesium seemed to increase the potash 
content of the leaves. Other workers (19, 70) have secured similar 
results. Data of foliage analyses frequently show wide variation which 
is to be expected since it is known that both climatic and soil conditions 
influence the mineral content of plant leaves. 

Some data of organic constituents of peanut hay are given in table 9. 



Table 9. — Average Percentage Composition of Mowed Peanut Hay, Compiled 
FROM Results of Fraps (30) 


Protein 


11.09 

5.09 

21.94 


Nitrogen-free extract 

Ash 


42 11 


Ether extract 


9.77 


Crude fiber 


Water . . . 


10 00 









According to Moore (59) when peanut plants were grown on a 
range of nitrogen levels from very high to very low, the foliage con- 
sistently increased in total sugars, starch and dextrians, while the per- 
centage of soluble solids and total nitrogen decreased as the nitrogen 
supply to the roots decreased. Hemicelluloses did not seem to be related 
to the nitrogen level on which the plants were grown. He suggested that 
total nitrogen rather than any specific nitrogen fraction should be used 
in correlating nutritional studies of the peanut. 

FOLIAR DIAGNOSIS 

Diagnostic methods involving analytical or plant-tissue tests have re- 
ceived considerable attention in recent years. In general, analyses of the 
entire plant are not recommended since specific tissues are considered 
to be more reliable as an indication of the mineral condition of the plant. 
Leaves are frequently chosen because their nutrient content more nearly 
reflects the supply from the soil. Standardization of tissue tests for known 
conditions may be useful especially when values of elements below the 
limits regarded as necessary for plant growth are the ones of interest 
from the viewpoint of fertilisation. 

Analyses of the peanut seed are of little diagnostic value since its 
mineral composition is relatively constant. The mineral content of the 
shell is influenced by nutrient supply but analyses of that organ would 
serve only as a fertilizer guide for the coming year. It would appear that 



PHYSIOLOGY AND MINERAL NUTRITION 113 

analyses of leaves or stems might be best for diagnostic purposes, 
especially if corrective measures are to be practiced. 

Studies of tissue tests with the peanut are limited, but they seem to 
merit more attention, especially evaluations for known or controlled con- 
ditions. Burkhart and Page (20, 61) found variations in mineral content 
of different parts of the foliage of the peanut and state that the following 
tissues were most indicative for specific tests: Calcium, lower blades; 
magnesium, lower petioles ; potassium, top petioles ; phosphorus, top 
blades; sulfur, lower stems. The lower leaf blades of the peanuts were 
thought to be the most suitable tissue for determining deficiencies or 
excesses of all mineral nutrients in the plant. Chemical tests of the lower 
blades gave results which correlated with response to fertilization of 
field-grown plants. 

SHEDDING OF FRUIT 

Since the peanut blooms during a period of 2 to 3 months, there are 
various stages of fruit development as the plant approaches maturity. 
Many crops of indeterminate growth habit are harvested two or three 
times during a season. This is impossible with the peanut plant, since it is 
removed from the soil in the process. If peanuts are harvested early, there 
will be a large number of immature fruit, and if late, the most mature 
fruit will be left in the soil by the harvesting process (11, 39, 57, 66). 
The amount of shedding or fruit loss is undoubtedly related to a number 
of factors such as the degree of ripeness, amount of disease, insect dam- 
age, and various cultural treatments. Different seed inoculations ( 1 ) have 
necessitated harvesting at different times, also applications of gypsum 
(19) have resulted in early defoliation, making early harvest necessary. 
Shedding was decreased by sulfur dusting (11, 39) and was also in- 
fluenced by fertilizer and other treatments (39). The number of fruit 
shed may be very few, but occasionally, when harvested late or under 
unusual conditions, as much as 75 percent (39) of all peanuts produced 
may be left in the soil after harvesting. Therefore, it is quite important 
in evaluating experimental results to know whether the technique used 
in harvesting accounts for all the peanuts produced. 

NUTRITIONAL BALANCE 

A lack of balance in nutrient supply (34, 49, 87) frequently accentu- 
ates nutritional disturbances. Published results ( 10, 19, 37) show that a 
deficiency of any element to the peanut will quickly produce abnormal 
plants which deteriorate rapidly. These deficiencies markedly affect the 



114 THE PEANUT— THE UNPREDICTABLE LEGUME 

vegetative character, flower and fruit production, and the mineral compo- 
sition of the plants. This balance relates not only to the nutrient supply 
in the root area, but also in the fruiting area. Plants are vegetative and 
produce few fruit when calcium is not applied to the fruiting area (10, 
37). Thus, the nature of the entire plant may be altered by the lack of 
calcium in the fruit zone. This does not mean that fruit absorption of 
nutrients is as important as root absorption, but the special requirements 
of the fruiting organs cannot be disregarded in the evaluation of fertilizer 
requirements. 

A number of workers (14, 15, 19, 20, 70) have emphasized the effect 
of the calcium-potassium relationship on fruit production. Others (83) 
have indicated that the potassium-magnesium ratio is important in this 
respect and that the relation of the calcium, potassium and magnesium 
supply was indicative of the relative yield of marketable nuts. The im- 
portance of a balanced ration for plants is obvious. However, it is impos- 
sible to strive for a balanced nutrient program for the peanut until factors 
responsible for yields are identified. 

NUTRITION AS RELATED TO DISEASE 

The relation of the nutritional status of the peanut plant to its disease 
susceptibility is probably more important than generally realized. The 
prevalence of leaf-spot infection was far greater on plants grown on a 
magnesium-deficient solution than of plants grown on a deficiency of 
other elements ( 12) . Applications of gypsum have also been reported ( 19) 
to cause the foliage of peanut to be very susceptible to leaf spot, resulting 
in early defoliation. 

Concealed damage of the peanut seed is any internal breakdown of the 
cotyledons which is not evident upon external examination. Wilson (92) 
indicates that one type of concealed damage appears to be physiological 
in nature, but its occurrence was unimportant in Alabama. Internal 
breakdown of the seed might be related to nutrition but experimental 
evidence of such is lacking. 

Sulfur dust is commonly applied to the foliage of peanuts to control 
leaf spot and certain insects. The sulfur may also act as a nutrient in 
some instances, especially where the supply of sulfur in the soil is low 
(8, 38). Some results^ suggest that when sulfur was applied to the soil 
the foliage of the peanut plant was less susceptible to the leaf-spot in- 
fection. 

5 Unpublished results, Florida Agricultural Experiment Station. 



PHYSIOLOGY AND MINERAL NUTRITION 115 

DISCUSSION 

Physiological processes relative to vegetative growth and fruit pro- 
duction of the peanut plant are assumed to be similar to those of many 
other plants. If dififerences exist, they are perhaps quantitative rather 
than qualitative. A balance of many physiological factors is necessary for 
the production of a healthy plant with a vigorous vegetative growth, many 
flowers, and adequate organic and inorganic reserves to support heavy 
fruiting. Whether the physical condition of the soil has an influence on 
penetration by the gynophore and subsequent development of the fruit is 
unknown. It has been shown that some mineral elements are absorbed 
by the fruiting organs and the data indicate that small amounts of available 
calcium in the fruiting zone aid fruit development. However, most of the 
mineral intake of the plant is by the root system. 

In most well-drained soils the penetration of roots is limited not by 
soil conditions but by factors inherent within the plant. The data suggest 
that the peanut plant has an extensive root system and the roots are more 
or less continuously growing through the soil and are constantly coming 
in contact with soil particles from which cations can be displaced and 
absorbed. There are no data comparing the mineral uptake by the peanut 
plant with that of other plants from the same medium. However, it ap- 
pears that the root system of the peanut is very efifective in extracting 
nutrients from sandy soils of low nutrient supply. Whether that effective- 
ness is related to the nature of absorbing roots or to the extensiveness of 
the root system of the plant or the combination of both factors is un- 
known. 

Physiological processes related to the nutrient supply in general 
determine the yield of field grown peanuts. The peanut is rather sensi- 
tive to an unbalanced nutrient supply and undoubtedly the application of 
one or two elements to the soil in some instances has produced an un- 
favorable nutrient balance which may account for some of the conflicting 
results of fertilizer field trials (11, 26, 39, 89) . The only pronounced yield 
responses reported with peanuts have been on restricted areas where the 
available soil supply of calcium (27, 54, 69, 70) , magnesium (70, 77, 78), 
or microelements (2, 6, 36, 71) has been very low. All these facts indicate 
the need for additional data in order to deal more effectively with the 
complex problems of soil and plant interrelations arising in the field. 

SELECTED REFERENCES 
(1) Albrecht, H. R. 

1944. factors influencing the effect of inoculation of peanuts grown 
ON NEW PEANUT LANDS. Soil Sci. Soc. Amer. Proc, 8:217-220. 



116 THE PEANUT— THE UNPREDICTABLE LEGUME 

(2) Allison, R. V., Bryan, O. C. and Hunter, J. H. 

1927. THE STIMULATION OF PLANT RESPONSE ON THE RAW PEAT SOILS OF THE 
FLORIDA EVERGLADES THROUGH THE USE OF COPPER SULFATE AND 

OTHER CHEMICALS. Fk. Agr. Exp. Sta. Bul. 190. 

(3) Anon. 

1947. EARLY LIFE OF PEANUTS STUDIED. N. C. Agr. Exp. StE., 70th Ann. Rpt., 
21-23. 

(4) 

1946. PEANUTS. N. C. Agr. Exp. Sta., 69th Ann. Rpt., 37-47. 

(5) Bailey, W. K., Pickett, T. A. and Futral, J. G. 

1947. PEANUT curing studies. I. effect OF HARVESTING AND CURING PRO- 

CEDURES ON QUALITY OF PEANUTS. Ga. Exp. Sta. Bul. 255. 

(6) Barnette, R. M., Camp, J. P., Warner, J. D. and Gall, O. E. 

1936. THE USE OF ZINC SULFATE UNDER CORN AND OTHER FIELD CROPS. Fla. 

Agr. Exp. Sta. Bul. 292. 

(7) Beattie, J. H., Jackson, A. M. and Currin, R. E. 

1932. effect of cold storage and age of seed on germination AND YIELD 

OF PEANUTS. U. S. D. A. Cir. 233. 

(8) Bledsoe, Roger W. and Blaser, R. E. 

1947. THE influence of sulfur on THE YIELD AND COMPOSITION OF CLOVERS 

fertilized WITH DIFFERENT SOURCES OF PHOSPHORUS. Jour. Amcr. 

Soc. Agron., 39:146-152. 

(9) Bledsoe, Roger W., Comar, C. L. and Harris, H. C. 

1949. absorption of radioactive calcium by the peanut fruit. Science, 

109:329-330. 

(10) Bledsoe, Roger W. and Harris, Henry C. 

1950. THE influence of mineral deficiency on vegetative growth, 

flower, fruit production and mineral composition of THE 

peanut plant. Plant Physiol., 25:63-77. 

(11) Bledsoe, Roger W., Harris, Henry C. and Clark, Fred. 

1945. THE importance of peanuts left in the soil in the interpretation 

of increases in yield due to sulfur treatments. Jour. Amer. Soc. 
Agron., 37:689-695. 

(12) Bledsoe, Roger W., Harris, Henry C. and Tisdale, W. B. 

1946. leaf spot of peanut associated with magnesium deficiency. Plant 

Physiol., 21:237-240. 

(13) Brady, N. C. , 

1948. the effect of calcium supply and mobility of calcium in the plant 

ON PEANUT FRUIT FILLING. Soil Sci. Soc. Amer. Proc, 12:336-341. 

(14) Brady, N. C. and Colwell, W. E. 

1945. YIELD and QUALITY OF LARGE-SEEDED TYPE PEANUTS AS AFFECTED BY 
POTASSIUM AND CERTAIN COMBINATIONS OF POTASSIUM, MAGNESIUM 

AND CALCIUM. Jour. Amer. Soc. Agron., 37:429-442. 

(15) Brady, N. C, Reed, J. F. and Colwell, W. E. 

1948. THE EFFECT OF CERTAIN MINERAL ELEMENTS ON PEANUT FRUIT FILLING. 

Jour. Amer. Soc. Agron., 40:155-167. 

(16) Brewer, H. E. 

1949. tetrazolium chloride as a test for damage in artificially cured 

PEANUTS. Science, 110:451-452. 



PHYSIOLOGY AND MINERAL NUTRITION 117 

(17) Bruner, W. E. 

1932. root development of cotton, peanuts and tobacco in central 

OKLAHOMA. Proc. Okla. Acad. Sci., 12:20-37. 

(18) BURKHART, LeLAND. 

1938. AMMONIUM NUTRITION AND METABOLISM OF ETIOLATED SEEDLINGS. Plant 

Physiol., 13:265-293. 

(19) BURKHART, LELAND AND COLLINS, E. R. 

1942. MINERAL NUTRIENTS IN PEANUT PLANT GROWTH. Soil Sci. SoC. Amer. 

Proc, 6:272-280. 

(20) BuRKHART, LELAND AND PAGE, N. R. 

1941. MINERAL NUTRIENT EXTRACTION AND DISTRIBUTION IN THE PEANUT 

PLANT. Jour. Amer. Soc. Agron., 33:743-755. 

(21) Cheliadinora, A. I. 

1941. influence of illumination INTENSITY UPON THE RESPONSE OF PEA- 
NUTS TO DAY-LENGTH. Comp. Rend. (Dok.) Acad. Sci., U. R. S. S., 
n. ser., 31, no. 3, pp. 276-278. (Abs. in Exp. Sta. Rec, 86:775). 

(22) 

1941. INFLUENCE OF TEMPERATURE ON THE RESPONSE OF ARACHIS HYPOGAEA 

L. TO DAY-LENGTH. Compt. Rend. (Dok.) Acad. Sci. U. R. S. S., n. 
ser. 31, no. 1, pp. 55-57. (Abs. in Exp. Sta. Rec, 86:775). 

(23) Chevalier, A. 

1933. MONOGRAPHIE DE l'arachide (i). Rev. Bot. Appliquee 13:689-789. 

(24) 

1934. MONOGRAPHIE DE l'arachide (ii). Idem, 14:565-632, 709-755, 833-864. 

(25) 

1936. MONOGRAPHIE DE l'arachide (ill). Idem, 16:673-871. 

(26) Collins, E. R. and Morris, H. D. 

1942. soil FERTILITY STUDIES WITH PEANUTS. N. C. Agr. Exp. Sta. Bui. 330. 

(27) COLWELL, W. E. AND Brady, N. C. 

1945. THE EI*ECT OF CALCIUM ON YIELD AND QUALITY OF LARGE-SEEDED TYPE 

PEANUTS. Jour. Amer. Soc. Agron., 37:413-428. 

(28) CoLWELL, W. E., Brady, N. C. and Piland, J. R. 

1945. COMPOSITION OF PEANUT SHELLS OF FILLED AND UNFILLED FRUITS AS 
AFFECTED BY FERTILIZER TREATMENTS. Jour. Amer. SoC Agron., 

37:792-805. 

(29) Dunn, Katharine R. and Goddard, Vera R. 

1948. effect of heat upon the nutritive values of peanuts. ii. ribo- 
FLAVIN AND PANTOTHENIC ACID CONTENT. Food ReS., 13:512-517. 

(30) FRAPS, G. S. 

1917. THE COMPOSITION OF PEANUTS AND PEANUT BY-PRODUCTS. Texas Agf. 

Exp. Sta. Bui. 222. 

(31) Gallup, Willis D. and Staten, H. W. 

1943. composition of several varieties of peanut plants and their 

parts in relation to feeding value and oil yield. a preliminary 
REPORT. Okla. Acad. Sci, Proc, 23:23-27. 

(32) Gilbert, S. G., Sell, H. M. and Drosdoff, M. 

1946. the effect of copper deficiency on the nitrogen metabolism and 

OIL SYNTHESIS OF THE TUNG TREE. Plant Physiol., 21 :290-303. 



118 THE PEANUT— THE UNPREDICTABLE LEGUME 

(33) Guthrie, John D., Hoffpauir, C. L., Stansbury, M. F. and Reeves, W. A. 

1949. SURVEY OF THE CHEMICAL COMPOSITION OF COTTON FIBERS, COTTONSEED, 
PEANUTS AND SWEET POTATOES. A LITERATURE REVIEW. U. S. D. A. 

Bur. Agr. and Ind. Chem. AIC-61. Revised Mar. 

(34) Hammer, C. L. 

1940. growth responses of biloxi soybeans to variations in relative 
concentrations of phosphate and nitrate in nutrient solution. 
Hot. Gaz., 101:637-649. 

(35) Harris, Henry C. 

1948. COPPER deficiency in relation TO THE NUTRITION OF OATS. Soil Sci. 

Soc. Amer. Proc, 12:278-281. 



1949. COPPER deficiency of peanuts. Proc. Asso. Southern Agr. Workers, 
46: (In press). 



(36) 

(37) 

1949. THE EFFECT ON THE GROWTH OF PEANUTS OF NUTRIENT DEFICIENCIES 
IN TNE ROOT AND THE PEGGING ZONE. Plant Physiol., 24:150-161. 

(38) Harris, Henry C., Bledsoe, Roger W. and Calhoun, P. W. 

1945. response of cotton to sulfur fertilization. Jour. Amer. Soc. 
Agron., 37:323-329. 

(39) Harris, Henry C, Tisdale, W. B. and Tissot, A. N. 

1947. importance of experimental technique in fertilizer, dusting 
and calcium experiments with florida runner peanuts. soil 
Sci. Soc. Amer. Proc, 11:413-416. 

(40) Higgins, B. B., Holley, K. T., Pickett, T. A. and Wheeler, C. D. 

1941. I. PEANUT breeding AND CHARACTERISTICS OF SOME NEW STRAINS. 
II. THIAMIN CHLORIDE AND NICOTINIC ACID CONTENT OF PEANUTS 
AND PEANUT PRODUCTS. Ill, PEPTIZATION OF PEANUT PROTEINS. Ga. 

Agr. Exp. Sta. Bui. 213. 

(41) Hoagland, D. R. 

1944. inorganic plant nutrition. Waltham, Mass. : Chronica Botanica Co. 

(42) Hoagland, D. R. and Arnon, D. I. 

1939. THE water-culture METHOD FOR GROWING PLANTS WITHOUT SOIL. 

Calif. Agr. Exp. Sta. Cir. 347. 

(43) Hoffpauir, C. L. and Guthrie, John D. 

1945. CHEMICAL composition OF PEANUTS. A LITERATURE REVIEW. Peanut 

Jour, and Nut World, 24 (No. 6) :26-30. 

(44) Hull, Fred H. 

1937. inheritance of rest period of seeds and certain other charac- 
TERS IN THE PEANUT. Fla. Agr. Exp. Sta. Bui. 314. 

(45) Jacobs, William P. 

1947. THE DEVELOPMENT OF THE GYNOPHORE OF THE PEANUT PLANT, ARACHIS 
HYPOGAEA L. I. THE DISTRIBUTION OF MITOSIS, THE REGION OF 
GREATEST ELONGATION, AND THE MAINTENANCE OF VASCULAR CON- 
TINUITY IN THE INTERCALARY MERisTEM. Amer. Jour. Bot., 34: 
361-370. 

(46) Jenny, H. and Overstreet, R. 

1939. cation interchange between plant roots and soil colloids. soil 
Sci., 47:257-272. 



PHYSIOLOGY AND MINERAL NUTRITION 119 

(47) JODiDi, Samuel L. 

1938. PRELIMINARY BIOCHEMICAL STUDIES ON EFFECTS OF CERTAIN ENVIRON- 
MENTAL FACTORS ON DEVELOPMENT AND COMPOSITION OF THE PEANUT. 

Jour. Agr. Res., 57:301-31L 

(48) KiLLiNGER, G. B., Stokes, W. E., Clark, Fred and Warner, J. D. 

1947. PEANUTS IN FLORIDA. Fla. Agr. Exp. Sta. Bui. 432. 

(49) LOEHWING, W. F. 

1928. CALCIUM, POTASSIUM AND IRON BALANCE IN CERTAIN CROP PLANTS IN 

RELATION TO THEIR METABOLISM. Plant Physiol., 3:261-275. 

(50) Maximov, Nicolai A. (edited by Harvey, R. B. and Murneek, A. E.) 

1938. plant physiology. New York: McGraw-Hill Book Company, Inc. 

(51) Mehlich, a. and Colwell, W. E. 

1946. absorption of calcium by peanuts from kaolin and bentonite at 

varying levels of calcium. Soil Sci., 61:369-374. 

(52) Mehlich, A. and Reed, J. Fielding. 

1947. THE influence of type of colloid and degree of calcium satura- 

tion ON fruit characteristics of PEANUTS. Soil Sci. Soc. Amer. 
Proc, 11:201-205. 

(53) Metcalf, Z. p. 

1937. peanut "'pouts". Science, 86:374. 

(54) Middleton, G. K., Colwell, W. E., Brady, N. C. and Schultz, E. F., Jr. 

1945. the behavior of four varieties of peanuts as affected by cal- 
CIUM AND potassium VARIABLES. Jour. Amer. Soc. Agron., 37: 443- 
457. 

(55) Middleton, G. K. and Harvey, P. H. 

1939. STUDIES OF THE FRUITING HABIT OF THE PEANUT. Jour. Elisha Mitchell 

Sci. Soc, 55:242. 

(56) Miller, Edwin C. 

1938. PLANT PHYSIOLOGY. Ncw York: McGraw-Hill Book Company, Inc. 

(57) Miller, Lawrence I. 

1942. PEANUT leaf SPOT AND LEAF HOPPER CONTROL. Va. Agr. Exp. Sta. 

Bui. 338. 

(58) Mohammad, Ali, Alam, Zafar and Khanna, Kidar Lal. 

1932. STUDIES ON germination and growth in GROUNDNUT (ARACHIS HY- 

pogaea linn.). Agr. and Livestock in India, 3:91-115 (no. 2). 

(59) Moore, Rufus H. 

1937. nutritional levels in the peanut plant. Bot. Gaz., 98:464-490. 

(60) Meyer, Bernard S. and Anderson, Donald B. 

1939. PLANT PHYSIOLOGY. New York: D'Van Nostrand Company, Inc. 

(61) Page, N. R. and Burkhart, L. 

1941. extraction and distribution of soluble minerals in the peanut 
PLANT. Proc. Assoc. Southern Agr. Workers, 42:210-211. 

(62) PaTEL, J. S. AND Seshadri, C. R. 

1935. OIL formation in groundnut with reference to quality. Indian 
Jour. Agr. Sci., 5 (Part II): 165-175. 

(63) Pettit, Anna S. 

1895. ARACHIS HYPOGAEA L. Mem. Torrey Bot. Club, 4:275-296. 



120 THE PEANUT— THE UNPREDICTABLE LEGUME 

(64) Pickett, T. A. 

194L VITAMINS IN PEANUTS AND SOME OF THEIR PRODUCTS WITH SPECIAL 
REFERENCE TO VITAMIN Bi AND THE PELLAGRA-PREVENTATIVE FACTOR. 

Ga. Agr. Exp. Sta. Cir. 128. 

(65) Pons, Walter A. Jr., Murray, Mildred D., O'Conner, Robert T. and 

Guthrie, John D. 

1948. storage of cottonseed and peanuts under conditions WHICH 
MINIMIZE SPECTROPHOTOMETRIC CHANGES IN THE EXTRACTED OIL. 

Jour. Am. Oil Chemists' Soc, 25:308-313. 

(66) Prince, Alton E. 

1944. DISEASES of PEANUTS IN NORTH CAROLINA. Plant Dis. Reporter, 28: 
1080-1081. 

(67) Reddi, K. K. AND Giri, K. V. 

1947. INFLUENCE OF VARIETY, MANURING AND GERMINATION ON VITAMIN Bi 

CONTENT OF GROUNDNUT. Current Sci., 16:285. (Chem. Abst., 43: 
6284. 1949). 

(68) Reed, Edward L. 

1924. anatomy, embryology and ecology of arachis hypogaea. bot. gaz., 
78:289-310. 

(69) Reed, J. Fielding and Brady, N. C. 

1948. time and method of supplying calcium as FACTORS AFFECTING PRO- 

DUCTION OF PEANUTS. Jour. Amer. Soc. Agron., 40:980-996. 

(70) Rogers, H. T. 

1948. liming for peanuts in relation to exchangeable soil calcium 
and effect on yield, quality and uptake of calcium and po- 
TASSIUM. Jour. Amer. Soc. Agron., 40:15-31. 

(71) Shear, G. M. and Batten, E. T. 

1948. manganese deficiency of peanuts ;n Virginia. Proc. Assoc. Southern 
Agr. Workers, 45:147-148. ,-' 

(72) Shear, G. M. and Miller, L. L 

1941. THRIPS INJURY OF PEANUT SEEDLINGS. The Plant Disease Reporter, 

25:470-474. 

(73) Shibuya, T. 

1938. forcing the germination of dormant seeds by means of growth 
HORMONE. Jour. Soc. Trop. Agr., Taihoku Imp. Univ., Taiwan, 
Japan, 10:1-8. 

(74) 

1935. MORPHOLOGICAL AND PHYSIOLOGICAL STUDIES ON THE FRUCTIFICATION 

OF PEANUTS. Mem. Fac. Sci. and Agr., Taihoku Imp. Univ., 17:1- 
120. 

(75) 

1938. PRELIMINARY STUDIES ON THE RESPONSES OF SEEDS TO THE HORMONE 
TREATMENT GIVING VERNALIZATION-LIKE EFFECT. Jour. Soc. TrOp. 

Agr., Taihoku Imp. Univ., Taiwan, Japan, 10:264-269. 

(76) Shive, J. W. AND Stahl, a. L. 

1927. CONSTANT RATES OF CONTINUOUS SOLUTION RENEWAL FOR PLANTS IN 

WATER CULTURES. Bot. Gaz., 84:317-323. 

(77) SoMMER, Anna L. and Baxter, Aaron. 

1942. DIFFERENCES IN GROWTH LIMITATION OF CERTAIN PLANTS BY MAGNESIUM 

AND MINOR-ELEMENT DEFICIENCIES. Plant PhysioL, 17:109-115. 



PHYSIOLOGY AND MINERAL NUTRITION 121 

(78) SoMMER, Anna L., Wear, John I. and Baxter, Aaron. 

1941. THE RESPONSE TO MAGNESIUM OF SIX DIFFERENT CROPS ON SIXTEEN 

ALABAMA SOILS. Soil Sci. Soc. Amer. Proc, 5:205-212. 

(79) Stansel, R. H. 

1935. PEANUT GROWING IN THE GULF COAST PRAIRIE OF TEXAS. Texas Agr. 

Exp. Sta. Bui. 503. 

(80) Stansbury, Mack F. and Guthrie, John D. 

1947. storage of cottonseed and peanuts under conditions which 

MINIMIZE CHANGES IN CHEMICAL COMPOSITION. Jour. Agr. Res., 75: 

49-61. 

(81) Stokes, W. E. and Hull, Fred H. 

1930. PEANUT BREEDING. Jour. Amer. Soc. Agron., 22:1004-1019. 

(82) Stout, P. R. and Meagher, W. R. 

1948. studies OF the molybdenum nutrition of plants WITH RADIOACTIVE 

MOLYBDENUM. Science, 108:471-473. 

(83) Strauss, J. L. and Grizzard, A. L. 

1948. THE effect of calcium, magnesium and POTASSIUM ON PEANUT 

YIELDS. Soil Sci. Soc. Amer. Proc, 12:348-352. 

(84) Thornton, G. D. and Broadbent, F. E. 

1948. preliminary greenhouse studies of the influence of nitrogen 

fertilization of peanuts on nodulation, yield and gynophore 
ABSORPTION OF THIS ELEMENT. Jour. Amer. Soc. Agron., 40:64-69. 

(85) Van der Volk, P. C. 

1914. RESEARCHES CONCERNING GEOCARPY. Pub. Sur la Physiologie Vegetale, 
Nimeque. 

(86) Vanselow, a. p. and Datta, Narayan P. 

1949. MOLYBDENUM DEFICIENCY OF THE CITRUS PLANT. Soil Sci., 67:363-375. 

(87) Wadleigh, C. H. 

1939. influence of varying cation proportions upon the growth of 
YOUNG COTTON PLANTS. Soil Sci., 48:109-120. 

(88) Waldron, R. a. 

1919. the peanut, its history, histology, physiology and utility. contr. 
Bot. Lab. Univ. Pennsylvania, 4:302-338. 

(89) West, H. O. 

1942. PEANUT PRODUCTION. Miss. Agr. Exp. Sta. Bui. 366. 

(90) WiNTON, A. L. 

1904. the ANATOMY OF THE PEANUT WITH SPECIAL REFERENCE TO ITS MICRO- 
SCOPIC IDENTIFICATION IN FOOD PRODUCTS. Conn. Agr. Exp. Sta. 
Ann. Rpt, 191-198. 

(91) WiNTON, Andrew L., and Winton, Kate B. 

1932. STRUCTURE AND COMPOSITION OF FOODS. New York: John Wiley and 
Sons, Inc. (pp. 497-512). 

(92) Wilson, Coyt. 

1947. CONCEALED DAMAGE OF PEANUTS IN ALABAMA. Phytopathology, 37: 
657-668. 

(93) WooDROOF, J. G., Thompson, Helen H. and Cecil, S. R. Peanut Oil. 

1946. I. the stability of peanut oil. ii. comparison of peanut oil with 
other cooking oils. Ga. Agr. Exp. Sta. Bui. 247. 



CHAPTER V 

SOIL PROPERTIES, FERTILIZA 
TION AND MAINTENANCE 
OF SOIL FERTILITY 

By 
E. T. YORK, JR. AND W. E. COLWELL^ 

Properties of Soils on Which Peanuts Are Grown 

GENERAL SOIL PROPERTIES 

A soil well adapted to the production of peanuts has often been char- 
acterized as a well-drained, light-colored, loose, friable, sandy loam, well 
supplied with calcium and with a moderate amount of organic matter. 
While such a soil may be considered to be "ideal," peanuts may be grown 
on soils dififering markedly in physical and chemical characteristics. 

A number of factors other than the yielding capacity of a soil deter- 
mines its suitability for the production of this crop.fPeanuts are normally 
grown on light sandy soils not necessarily because these soils produce the 
highest yields; in fact, there are many indications that better yields 
may be obtained on some of the heavier-textured soils. The principal 
reason for growing peanuts on the lighter soils lies in the fact that the 
crop is more easily harvested and the soil does not adhere to the pods./ 
Many of the heavier-textured clays and clay loams are more deeply 
colored and tend to stain the pods to such an extent as to lower the 
market value of the crop. These factors are of little consequence when 
the crop is harvested by grazing hogs ; however, it would not be a de- 

lE. T. York is associate professor of agronomy. North Carolina Agricultural Experiment 
Station, and W. E. Colwell is head. Department of Agronomy, North Carolina State College of 
Agriculture. 

The authors are indebted to J. F, Reed for his suggestions regarding the arrangement of sub- 
ject matter to be presented in this chapter and to W. L, Nelson for his constructive criticisms in 
the preparation of the manuscript. 

122 



SOIL FERTILITY 123 

sirable practice to harvest nuts by hogs on many of the heavier^soils be- 
cause of the likelihood of damage to the physical structure of the soil. 

Extremely heavy, sticky clays which tend to cake or crust are not 
well suited to peanut production because of the difficulty of peg pene- 
tration at fruiting time. 

Under favorable conditions it is difficult at times to secure good 
stands of peanuts, and in wet, poorly drained soils satisfactory stands are 
virtually an impossibility. Peanuts have a distinct taproot and, as with 
other deep-rooted plants, it is essential that they be grown on a well- 
aereated soil with good drainage. 

Variations in the chemical properties of peanut soils are limited some- 
what by the exacting demands for proper physical characteristics. Soils 
of desirable color, texture and drainage usually have a relatively low ex- 
change capacity ... in most cases between one and five milliequivalents 
per 100 grams of soil. These soils are generally low in organic matter 
and reserves of plant nutrients. While peanuts may appear to make fair 
yields on land too poor for most other crops, it should not be implied that 
this crop is best adapted to relatively infertile soils. The fact that peanuts 
are grown on soils of low native fertility merely emphasizes the need for 
an extremely careful program of fertilization and management in order to 
maintain a high level of production of peanuts and other crops grown 
in the rotation. 

PROPERTIES OF SOILS IN VARIOUS PEANUT 
PRODUCING AREAS 

(1) The United States: The majority of the peanuts produced in the 
southeastern United States are grown on Coastal Plain soils. Batten 
(29) considers the Norfolk fine sandy loam as the soil best suited to 
growing the large-seeded type peanut ; and a large acreage of the peanut 
crop grown in North Carolina and Virginia is produced on soils of the 
Norfolk series. The Sassafras, Marlboro, Moyock and Craven are also 
considered to be good peanut soils, while the poorly drained Bladen and 
Portsmouth soils are not adapted to growing this crop (29). 

Generally, the soils of the small-seeded Peanut Belt in Georgia, 
Alabama and Florida are more sandy and have a lower exchange capacity 
and organic-matter content than the peanut soils of the Virginia-Carolina 
area. The Alabama Agricultural Experiment Station reports (4) that 
high yields of peanuts have been obtained on all the major soil areas of 
that State. However, most of the crop grown for market is produced on 
the light, sandy. Coastal Plain soils of the southeastern part of the State. 



124 THE PEANUT— THE UNPREDICTABLE LEGUME 

Most of the well-drained soils in central and northern Florida are 
satisfactory for growing peanuts, according to Killinger et al. (65) at 
the Florida Experiment Station. These workers have observed that some 
of the waste-pond phosphate fields and areas surrounding phosphate 
mines and lime quarries are especially well adapted to the production of 
high yields of peanuts. The Norfolk, Arredondo, Newberry, Orange- 
burg, Ruston, Red Bay and Magnolia soil series are commonly used for 
growing peanuts in Florida, while the "flatwood soils" are considered 
poor for the production of this crop. 

Parham (84) reports that most of the peanuts produced in Georgia 
are grown on Coastal Plain soils in the southern part of the State. In 
areas where the peanuts are produced for market, the crop is grown on 
some of the relatively heavy soils such as the Greenville, Magnolia and 
Orangeburg. Lighter soils such as the Norfolk, Tifton and Ruston are 
used primarily in areas where the peanuts are hogged oflf, according to 
Parham. 

Downing, Aull, Goodman and Peterson (48) have classified the soils 
of South Carolina into four groups based on their suitability for growing 
peanuts. A description of these groups follows: 

"Group A: Excellent soil types for peanuts. Generally well drained 
with sandy loam or similar textured surface layers and with friable sandy 
clay loam on sandy clay subsoils beginning 10 to 24 inches below the 
surface. The soil as a whole is at least 36 to 48 inches deep and may be 
more. The topography is favorable for tillage operations and erosion is 
not a major problem. 

"Group B : Good soil types for peanuts. Soils in this group, though 
generally similar to those in Group A, differ in characteristics such as 
thickness or texture of the surface layer, internal drainage, gravelliness 
or stoniness, or slope. The surface layer of a good soil may have either a 
lighter or heavier texture and may be shallower or deeper than that of 
an excellent soil. 

"Group C : Fair soil types for peanuts. Soils in this group usually 
have one or more unfavorable characteristics such as a fine textured, 
very coarse textured, or very deep open or sandy upper layer, a notice- 
able eroded condition, steep slope, or imperfect drainage. 

"Group D : Poor soil types for peanuts. Soils in this group are poor 
for peanuts because of characteristics that limit production or prevent 
proper cultivation of the land. Included are very sandy, very clayey, 
hilly to mountainous, wet or swampy, and rocky soils. If these soils are 
used for peanuts, yields will be very low." These suitability groups might 
well apply to soils of other peanut-producing regions. 



SOIL FERTILITY 125 

The peanuts produced in other States in the South and Southwest 
(41, 67, 103) are grown on soils similar in physical and chemical charac- 
teristics to those used in the major peanut-producing areas in the South- 
east. 

(2) Other parts of the World : Workers in Jamaica (-24, 25), Hawaii 
(66), Mexico (70), Cuba (109), Columbia (22), the Philippines (51), 
Australia (63, 64, 90, 111), Senegal (26), South Africa (79, 92, 98), 
Indonesia (23) and Rhodesia (108) have reported that the soils best 
suited for peanut production in their respective countries were, in general, 
those having the characteristics of the "ideal" peanut soil described 
earlier in this chapter. Hence it is evident that there is universal agree- 
ment on what constitutes the most desirable soil for growing peanuts. 

THE FERTILIZATION OF PEANUTS 

Peanut-fertilization practices have changed little in the United States 
in the past several decades ; significantly, perhaps, neither have the yields. 
This is in sharp contrast to most of the other crops grown in the same 
areas. 

A review of the peanut fertility research conducted by the southeast- 
ern experiment stations reveals a multitude of inconsistent and apparently 
conflicting data. The anomalous behavior of the peanut is pointed out as 
follows in a report of a recent study by the Southern Research Institute 
(21): 

"Not only does the peanut fail to respond markedly to direct ap- 
plications of commercial fertilizers, but such responses as are observed 
are not constant, varying widely from field to field even on the same 
soil type. This behavior is in marked contrast to that of other crops 
such as corn or cotton for which the yield increase to be obtained for a 
given application of fertilizer can be predicted with almost mathe- 
matical certainty." 

Despite this unusual behavior, peanuts are not unlike other crops in 
their basic nutritional requirements. In fact, with the normal systems 
of management in which both hay and nuts are harvested, peanuts re- 
move relatively large amounts of nutrients from a soil (table 1). Cer- 
tainly there is little reason to suspect that the chemical and physical laws 
which govern the absorption and utilization of nutrients by peanuts are 
not the same as for other plants. What accounts, therefore, for the erratic 
behavior of the peanut in response to fertilizer amendments ? 

Until recently little attention has been given to the fact that peanut 
varieties exhibit marked differences in nutrient requirements. Yet, while 



126 



THE PEANUT— THE UNPREDICTABLE LEGUME 



striking differences among varieties in their response to fertilization may 
be reconciled, the anomalous, inconsistent results often obtained in ferti- 
lizer experiments with a single variety have been more difficult to under- 
stand. As pointed out in Chapter III, peanuts are normally self-pol- 
linated, and the plants within a given newly selected strain or variety are 
essentially homogeneous. Therefore, genetic variability should be at a 
minimum and observed differences within such a variety must necessarily 
be a result of environmental influences. Failure to evaluate fully the 
various environmental factors influencing the growth of peanuts has 
made it difficult to interpret much of the experimental data. 

Table 1. — Nutrients Removed from the Soil by One Ton of Peanuts and Two 
Tons of Hay (Pounds per Acre). Collins and Morris (43). 



Part of 
the Plant 


Yield per 

Acre 
Pounds 


N 
Pounds 


Pounds 


Pounds 


CaO 
Pounds 


MgO 
Pounds 


Hay 

Kernels 

Hulls 


4,000 

1,280 

720 


78.80 

56.30 

4.60 


10.60 

12.90 

0.80 


82.20 

10.90 

9.90 


55.00 
1.10 
2.83 


25.20 
4.00 
1.10 


Total pounc 
vidual nu 
removed 

Percent of t 
ents in ha 


s of indi- 
trients 

otal nutri- 
V 


139.70 
56.40 


24.30 
43.60 


103.00 
79.80 


58.90 
93.40 


30.30 
83.20 







As pointed out previously, peanuts are often grown on soils of low 
native fertility. In many cases these soils are already deficient or on the 
threshhold of being deficient in a number of essential elements. It is 
common knowledge that under conditions where two or more nutrient 
elements are limiting growth, little benefit is derived from one nutrient 
unless all of the deficient elements are supplied simultaneously. The fact 
that peanuts often fail to respond to certain fertilizers may be due in part 
to a state of multiple nutrient deficiency. 

It is difficult to evaluate much of the peanut fertility data in the litera- 
ture because of the lack of information concerning the soil on which the 
work was conducted. A rather complete characterization of the physical 
and chemical properties of the soil would undoubtedly facilitate a better 
understanding of the experimental work with peanuts. Furthermore, an 
interpretation of peanut-fertilization data must also take into account 
the previous cropping and fertilization history of the soil. 

Failure to appreciate fully the unique growth and fruiting habits of 
the peanut has certainly led to some of the confusion regarding the ferti- 



SOIL FERTILITY 127 

lization of this crop. Since nutrients may be absorbed by the developing 
pegs as well as by the roots (34, 40, 110), the problem of fertilizer 
placement becomes of greater importance with peanuts than with many 
other crops. Recent experiments (20, 38, 45) indicate that to obtain the 
most beneficial effect of some nutrients, they must be supplied to the 
zone of fruit formation rather than to the plant roots. On the other hand, 
there are indications that it is best to supply certain other nutrients to 
the rooting medium (20, 37, 40). Another problem associated with ferti- 
lizer placement results from the fact that stand injury may occur when 
certain fertilizer materials are placed too close to the seed at planting 
(20, 31). Obviously the effectiveness of fertilizer materials may, to a 
large extent, depend upon proper placement, and such materials may 
lower yields unless they are used correctly. 

The yield of peanuts may be influenced greatly by the stage of ma- 
turity of the plant at harvesting. If the crop is harvested early, a large 
proportion of the nuts is immature. Yet, if harvesting is delayed too long, 
an excessive number of the nuts may be separated from the vines and 
remain in the soil. There is evidence in the literature that certain fertility 
treatments may hasten or delay the maturity of the plants (30, 89). 
Certainly, plants must be harvested at comparable stages of maturity if 
the effects of fertilizer amendments are to be measured accurately. 

Recent work has indicated that fertilizer treatments may influence 
the number of nuts which are shed and remain in the soil at harvest (35, 
58). Therefore, this differential effect of fertilizers upon shedding may 
influence the yield of peanuts as normally measured. Perhaps the effect of 
certain fertilizer materials upon shedding is related directly to their in- 
fluence upon maturity. 

It should be evident from the foregoing discussion that peanut ferti- 
lization practices are not as well defined as with many other crops, and 
many of the anomalies associated with peanut fertilization are yet to be 
explained. Without question, experimental work with peanuts presents 
problems and requires techniques which are quite specific to this crop. 
However, when due consideration is given to the peculiar fruiting habits 
of the peanut plant as well as to the many important, but often unrecog- 
nized, environmental factors which influence its behavior, the available 
information pertaining to the fertilization of peanuts begins to assume a 
much more orderly pattern. 

No attempt will be made in this discussion to review all of the experi- 
mental work with peanut fertility. Such a review would undoubtedly tend 
to confuse rather than clarify the issue because of the difficulty in eval- 



128 THE PEANUT— THE UNPREDICTABLE LEGUME 

uating much of the data in the literature due to the lack of information 
regarding the conditions of the experiments. Instead, certain data will be 
presented which tend to illustrate specific principles regarding the fertili- 
zation of peanuts and the maintenance of the fertility of peanut soils. 
From these data, it should be possible to formulate some fairly definite 
ideas regarding the use of fertilizer materials with peanuts. 

EXPERIMENTS WITH NITROGEN, PHOSPHORUS 
AND POTASSIUM 

Nitrogen 

Being a leguminous plant, peanuts might not be expected to respond 
to large applications of nitrogen, and some of the experimental data would 
tend to verify this supposition. However, there is also considerable evi- 
dence which would indicate that nitrogen is of value in peanut fertilizers. 

Recently, Prevot (91) has emphasized the importance of nitrogen in 
the nutrition of peanuts. The data presented by this French worker indi- 
cate that relatively large quantities of nitrogen are translocated from the 
leaves to the developing fruit, suggesting the importance of maintaining 
the peanut plant at a high level of nitrogen metabolism prior to the fruit- 
ing period. However, no evidence is presented by Prevot to indicate that 
amendments of nitrogen would be necessary when the peanut plant was 
properly inoculated with nitrogen-fixing microorganisms. 

Responses to nitrogen might be expected if peanuts have not been well 
inoculated. While it has been generally assumed that no inoculation is 
necessary if peanuts are grown on land used previously for this crop, little 
has been done to determine if the most satisfactory inoculum is commonly 
present in peanut soils. Symbiotic nitrogen fixation may be inhibited 
somewhat in acid soils (69) ; hence response to nitrogenous fertilizers 
might be more pronounced on such soils. Unfortunately, most nitrogen- 
fertilization data in the literature are not accompanied with information 
relative to soil pH and to the degree of inoculation of the peanuts grown 
in the experiments. 

It has been suggested (30) that nitrogen may be beneficial on soils 
which are extremely low in organic matter. Certainly differences in ni- 
trogen levels in soils would be expected to be reflected in the response 
of peanuts to additions of nitrogenous fertilizers. 

Workers at the Georgia Experiment Station (9) have found that 
nitrogen applied to Spanish peanuts caused a marked reduction in the 
disease. Southern root rot (Sclerofiiim rolfsii), and it was observed that 



SOIL FERTILITY 



129 



the yields of peanuts closely followed the incidence of the disease. These 
data would suggest that in some cases the beneficial effect of nitrogen 
may be due to its secondary influence in reducing the severity of this 
disease. 

The results of experiments conducted over a 10-year period at the 
Georgia Coastal Plain Experiment Station (13) show a small, progres- 
sive increase in peanut yields with each increment of nitrogen up to 32 
pounds. The maximum response, however, was only 151 pounds of nuts. 
In another single-element experiment there was little effect on yields of 
withholding nitrogen from a complete fertilizer (12). 

As the result of several years of experimentation, workers at the 
North Carolina Station (43, 47) have concluded that nitrogen fertilizers 
have little effect upon the yields of large-seeded peanuts. 

Several experiments conducted in Mississippi and reported by West 
(112) show little beneficial effect of 16 or 32 pounds of nitrogen in a 
complete fertilizer. In some cases the addition of nitrogen tended to re- 
sult in a lower yield of nuts. The results of other work reported by West 
show responses of 200 to 300 pounds of nuts from the application of 100 
pounds of nitrate of soda as a side dressing. 

McClelland (68) in Arkansas, has reported that the addition of 18 
pounds of nitrogen to a White Spanish variety resulted in an increased 
yield of 1,188 pounds of nuts and 1.38 tons of hay. 

Earlier work at the Alabama Experiment Station (49) indicated that 
nitrogen was of little value in peanut fertilizers. However, more recent 
experiments (1, 107) have revealed some marked responses from the ad- 
dition of nitrogen to Spanish peanuts. The data in table 2, obtained by 
the Alabama workers, show that in 1943 the yield of nuts was more than 
doubled by the addition of 120 pounds of nitrogen as nitrate of soda to a 



Table 2. — The Response of Spanish Peanuts to Additions of Nitrogen on a 
Norfolk Sandy Loam. Reported by Alabama Agricultural Experiment 

Station. (1) 





Pounds per Acre 


Treatment^ 


1943 


1944 


Average 




Nuts 


Hay 


Nuts 


Hay 


Nuts 


Hay 


TVo nitroe^en ,...'. 


787 
1,909 


2,279 
3,395 


1,508 
2,298 


4,503 
6,008 


1,148 
2,104 


3,391 


120 pounds nitrogen 

(750 pounds nitrate of soda) 


4,702 



»A1I plots received 1,000 pounds of superphosphate and 250 poynds of njuriate of potash per agre. 



130 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Norfolk sandy loam. The 2-year averages show an increase in yield of 
956 pounds of nuts due to the applied nitrogen. Furthermore, large in- 
creases in hay yields resulted from the added nitrogen. These data are 
sharply in contrast with those obtained in earlier experiments with 
smaller rates of nitrogen. 

The results of experiments conducted at two other locations in Ala- 
bama in 1944 are shown in table 3. The yields of Spanish peanuts were 
increased with each successive increment of nitrogen up to 80 pounds. 
The seed yield of runner peanuts was not increased by applications of 
nitrogen greater than 20 pounds per acre. However, the vegetative growth 
of both runner and Spanish type peanuts was stimulated by the added 
nitrogen. The Alabama workers (107) report that the high levels of 

Table 3. — The Influence of Amendments of Nitrogen upon the Yields of 

Spanish and Runner Peanuts on a Norfolk Sandy Loam. Reported by Alabama 

Agricultural Experiment Station. (1) 



Treatment^ 


Yield of runner'- 
Peanuts 


Yield of Spanish'' 
Peanuts 




Pounds per Acre 


Pounds per Acre 


None 

20 pounds nitrogen" 

40 pounds nitrogen 


1,429 
1,617 
1,605 

1,544 
1,635 


1,044 
1,202 
1,352 




1,626 


120 pounds nitrogen 


1,686 



» Peanuts were inoculated. 

''All plots received 1,000 pounds superphosphate and 250 pounds muriate of potash per acre, 

• Nitrogen applied as nitrate of soda. 

nitrogen did not afifect the percentage of sound or mature kernel, rotten 
kernels, or pops of either Spanish or runner type. 

In view of some of these data which show highly profitable responses 
from the application of nitrogen to peanuts, it might be well to re-examine 
some of the earlier work with this element. In most of these experiments 
less than 32 pounds of nitrogen were used, and in many cases recom- 
mendations are based on studies in which only 6 to 8 pounds of N per 
acre were applied. The recent work at the Alabama Station suggests 
that these amounts of nitrogen are insufficient to realize a measurable in- 
crease in peanut yields. 

In 1922, Batten (30) in experiments with large-seeded peanuts re- 
ported that large quantities of nitrogen used on fairly fertile soil generally 
stimulated the top growth, delayed the maturity, and resulted in peanuts 
of poor quality without materially increasing the yields. Other investiga- 



SOIL FERTILITY 131 

tors (96) have indicated that nitrogen may stimulate vegetative growth; 
however, the increased growth is often of little benefit because of the cor- 
responding reduction in the shelling percentage of nuts. From our present 
knowledge of peanut nutrition it appears possible that the poor quality of 
nuts might have been due in many cases to a deficiency of calcium. Cer- 
tainly the need for calcium and other nutrients would increase as the 
vegetative growth was stimulated, and little beneficial effect from nitro- 
gen could be expected if some other nutrient were limiting. 

In view of the conflicting evidence in the literature, it is not possible 
to reach a satisfactory conclusion relative to the use of nitrogenous 
fertilizers with peanuts. However, there are sufficient data to suggest the 
possibility of obtaining profitable responses from nitrogen when adequate 
supplies of other nutrients are present. Surely this problem warrants 
further investigation. 

Phosphorus 

There is considerable disagreement in the literature regarding the 
value of phosphorus in peanut fertilizers. Harper (56) and Pate (85) 
have indicated that phosphorus stimulates the setting of fruit and de- 
creases the number of unfilled pods. Other workers (89, 108) have sug- 
gested that phosphorus may hasten the maturity of peanuts. While there 
is no question regarding the plant's need for phosphorus, table 1 shows 
that a relatively small amount of this element is absorbed by the peanut 
plant and suggests that little may be gained from large applications of 
phosphatic fertilizers except, perhaps, on soils extremely low in avail- 
able phosphorus. 

Some of the earlier work in the United States and in several foreign 
countries indicates that a greater yield response might be obtained from 
phosphorus than from either nitrogen or potash. Batten (30) in 1922 re- 
ported that phosphorus gave better results than any other element in 
peanut fertilizers and recommended the use of 300 to 500 pounds per 
acre of superphosphate. On some of the Black Belt soils of Alabama, 
peanuts were found to be more responsive to phosphorus than to any 
other element (3). As the result of experiments conducted in Mississippi, 
Ferris (52) in 1922 concluded that "acid phosphate" gave the cheapest 
increase in the production of peanuts. 

Kerle (62), in New South Wales, indicated that superphosphate had 
proven to be the most beneficial fertilizer for peanuts in that country. 
Moses and Sellschop (79), in South Africa, reported profitable increases 
in peanut yields from the use of 300 pounds of superphosphate. Krauss 



132 THE PEANUT— THE UNPREDICTABLE LEGUME 

(66) has indicated that appHcations of 250 to 500 pounds of phosphate 
to peanuts in Hawaii have been very beneficial. 

In a recent experiment conducted by Massibot and Vidal (71) in 
Senegal, phosphate at the rate of 132 kilograms per hectare (approxi- 
mately 125 pounds per acre) was found to increase markedly the yields of 
peanut hay and nuts. The large responses to phosphorus were obtained on 
a soil which had been fallow for 2 years. These workers also observed 
that peanut yields were increased as the result of the residual effect of 
phosphatic fertilizers applied the previous year to millet. 

Numerous field experiments with peanuts conducted by the North 
Carolina Agricultural Experiment Station (46, 47) have failed to show 
any marked beneficial effect of phosphatic fertilizers when peanuts were 
grown in rotation with other crops which had received liberal applica- 
tions of phosphatic fertilizers. However, when peanuts were grown con- 
tinuously on the same soil, yields were increased by additions of phosphate 
on soils low in available phosphorus (16). 

The results of a 10-year study at the Georgia Coastal Plain Experi- 
ment Station (13) in which peanuts were grown after crops which had 
been "fairly well" fertilized showed no effect of additions of 48 pounds 
of P2O5 on peanut yields. In experiments conducted at several locations 
by the Georgia Experiment Station (6) on soils which had been "well 
fertilized in past years," little response was observed from applications 
of phosphorus. 

The behavior of peanuts toward amendments of phosphatic fertilizers 
appears to be dependent upon a number of factors. If the crop is grown 
on "new" land or land which has been fallow for a number of years, or in 
a rotation with other nonfertilized crops, phosphatic fertilizers would un- 
doubtedly be beneficial in many instances. However, when grown in ro- 
tation with other well-fertilized crops, peanuts might be expected to give 
little response to phosphorus amendments. 

In view of the rather exacting demands of some varieties of peanuts 
for calcium, some of the increases in yields which have been attributed to 
phosphorus may have been due to the calcium supplied in the phosphatic 
fertilizers. Evidence of this is found in the work of Albrecht (27) which 
shows that the addition of superphosphate to Spanish peanuts favorably 
influenced yields while triple superphosphate was of no value. O'Brien 
(82) has also found that superphosphate and dicalcium phosphate were 
superior to triple superphosphate as a source of phosphorus for peanuts. 
Ordinary superphosphate is approximately 50 percent by weight of cal- 
cium sulfate. 



SOIL FERTILITY 



133 



Potassium 

It is well recognized that peanuts are especially heavy "feeders" of 
potassium. Yet, despite the relatively large amount of potassium absorbed 
by peanuts (see table 1) the yield responses to applications of potash 
fertilizers are often very small or negligible, even on soils of low K con- 
tent. In fact, peanuts appear to be quite unique in their ability to absorb, 
potassium and make satisfactory growth on soils so deficient in available 
potassium that many other crops would fail to grow. 

An average of the yields obtained in an experiment conducted at the 
Georgia Coastal Plain Experiment Station (13) over a 10-year period 
shows that the use of 32 pounds of potash in combination with nitrogen 
and phosphorus increased the yield of Spanish peanuts only 139 pounds 
per acre. In experiments conducted by the North Carolina Station (46) 
between 1938 and 1943, 12 to 48 pounds of K^O per acre proved bene- 
ficial in only one of the locations. In several instances the yields were 
actually reduced by the application of potash. The exchangeable potassium 
level of these soils was 75 pounds or greater at each location. 



CORRECTED YIELD 
IN POUNDS 
PER ACRE 




NO 
CALCIUM 



WITH 
CALCIUM 



TRUE SHELLING 
PER CENT 



O = NO TREATMENT 
K = 48 LBS. 



KgO 



K 









n 


m 







i 


1 


t^ 




K 




dO 


m 




(NJ 


m 


1 



NO 
CALCIUM 



WITH 
CALCIUM 



Courtesy North Carolina Agricultural Experiment Station (47) 

Figure 1. — The response of peanuts to potash, with and without addi- 
tions of calcium. Soil = Kalmia sandy loam ; pH = S.3 ; exchange 
capacity = 3.13 m.e./lOO grams ; exchangeable Ca, Mg, and K = 
O.SO, 0.27 and 0.12 m.e./lOO grams respectively. Calcium equiva- 
lent to 130 pounds CaO was applied as CaS04.2H20 on the 
foliage in July. 



134 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Other experiments conducted in North Carolina (18, 37, 47) in 
1942, 1943 and 1944 revealed some interesting relations regarding the 
response of peanuts to potash. It was found that on a soil low in both 
potassium and calcium there was a significant increase in yield from 
the addition of potash when adequate calcium was supplied. Without the 
addition of calcium, potash was found to decrease the yields of peanuts, 
however. This relation is illustrated in figure 1. Apparently the deleteri- 
ous effect of potash in the absence of applied calcium was due to the re- 
duction in shelling percentage (figure 1). As shown in figure 2, the re- 
sponse of peanuts to potash was found to be dependent upon the initial 
level of potassium in the soil. On soils at a medium potassium level, ferti- 
lizers containing this element were of little value. It was observed that 
the vegetative growth was stimulated by the added potash and that the 
increased yields were due to the effect of the potash on the plant size and 
number of fruit rather than on kernel development. Other workers (40, 
76, 96) have also observed that potash may stimulate vegetative growth 



CORRECTED YIELD 
IN POUNDS 
PER ACRE 

O = NO TREATMENT 
K = 48 LBS KjO 

O 




SOIL LOW 
IN POTASH 



SOIL MEDIUM 
IN POTASH 



TRUE SHELLING 
PER CENT 



SOIL LOW 
IN POTASH 













K 

1^1 






CD 
CD 





1 1^1 

ho I 



SOIL MEDIUM 
IN POTASH 



CALCIUM REQUIREMENTS MET ON BOTH SOILS 

Courtesy North Carolina Agricultural Experiment Station (47) 

Figure 2. — The response of peanuts to potash amendments on soils containing 
different amounts of exchangeable potash. Soil low in potash was a Norfolk 
sand with 0.04 m.e. exchangeable K; soil medium in potash was a Norfolk 
sandy loam containing 0.10 m.e. exchangeable K per 100 grams. 



SOIL FERTILITY 135 

but cause a reduction in peanut quality. However, under the conditions 
reported in figure 1, this harmful effect of potash on peanut quality was 
overcome by maintaining an adequate level of calcium in the soil. 

Other studies in Georgia (6, 7, 8, 13), Florida (S, 65, 105), Alabama 
(1, 49), Mississippi (14), South CaroHna (83) and elsewhere (67) have 
given no consistent results with potash fertilizers, and it would be im- 
possible to: rnake a recommendation regarding the use of potash which 
would ,be applicable under all conditions. Generally the consensus among 
the southeastern experiment stations is that it is preferable to apply rela- 
tively large amounts of potash to the other crops grown in the rotation 
rather than to supply this material directly to peanuts. However, on soils 
extremely low in potassium or where heavily fertilized crops are not in- 
cluded in the rotation, it may be desirable to apply some potash directly 
to the peanuts. 

There is evidence that potash applied to peanuts may be harmful if 
the material is not used properly. Experiments in North Carolina (20) 
have shown that stands of peanuts were significantly reduced when 
either muriate of potash or potassium metaphosphate was placed directly 
underneath the seed. Furthermore, when potash was applied on top of the 
row (in the pegging zone) as late as June 15, yields were decreased and 
a large number of undeveloped- kernels or "pops" resulted. The practice of 
applying potash to the top of the row as the plants come through the 
ground has been found to be satisfactory in some localities (20). Investi- 
gators in Virginia (31) have observed no reduction in peanut stands 
when potash fertilizers were placed in bands at least 2 inches to the side 
of the seed and below the seed level. Thus side placement at planting or 
top dressing at emergence would appear to be the best method of applying 
potash fertilizers directly to peanuts. 

EXPERIMENTS WITH CALCIC MATERIALS 

The calcium requirements of the peanut plant have long been recog- 
nized. Jones (61) in 1885, describing a soil suitable for the growing of 
peanuts, said, "Unless (the soil) contains a goodly percentage of lime in 
some form in an available state, no land will produce a paying crop of 
pods, although it may yield large luxuriant vines." In a subsequent dis- 
cussion, Jones pointed out that a soil must contain adequate calcium in 
order to insure "solid pods." Thus, the need for and function of calcium in 
the production of peanuts was recognized some 65 years ago and perhaps 
earlier. 



136 



THE PEANUT— THE UNPREDICTABLE LEGUME 



The Importance of Calcium in Peanut Nutrition 

The significance of calcium in the nutrition of peanuts is clearly de- 
picted in figure 3. The data in this graph were obtained in experiments 
conducted by the staff at the North Carolina Agricultural Experiment 
Station (47) on soils ranging in calcium levels from approximately 450 
pounds to 2,200 pounds of calcium-carbonate equivalent per acre. Very 
marked increases in yields were obtained from additions of gypsum, a 
soluble calcium salt, to soils low in calcium. Yet it is evident that little 
might be gained from amendments of gypsum to soils already well sup- 
plied with calcium. Furthermore, it is obvious that increases in yields ob- 
tained from the gypsum on low calcium soils were due for a large part 
to the effect of the calcium on the shelling percentage. 



CORRECTED YIELD IN 
POUNDS PER ACRE 




TRUE SHELLING 
PER CENT 



A - NO TREATMENT 
B = GYPSUM 




Courtesy North Carolina Agricultural Experiment Station (47) 

Figure 3. — The effect of gypsum upon the yields and shelling percentage of peanuts 
growns on soils of different calcium levels. 



Chemical Characteristics 

pH -. 

Exchange Capacity — m.e./lOO gms 

Exchangeable Ca — m.e./lOO gms 

Exchangeable K — ^m.e./lOO gms 

Exchangeable Mg — m.e./lOO gms 



Soil Low 
■in Calcium 



Soil Medium 
in Calcium 



Soil High 
in Caliium 



6.0 

2.66 

0.45 

Oi05 

0.18 



5.5 

3.24 

1..19 

0.08 

0.29 



5.6 

4.02 

2.21 

0.10 

0.38 



SOIL FERTILITY 137 

Many other investigators (80, 109) have indicated that the quality of 
peanuts is influenced by calcium to a greater extent than is the quantity 
of fruit. A deficiency of calcium in soils is usually manifested by a large 
number of "pops" or unfilled pods. The better quality of nuts in soils well 
supplied with calcium is evidenced by a whiter, firmer hull, well-de- 
veloped kernels and an increase in weight per bushel of unshelled nuts. 
Colwell and Brady (44) have observed that in addition to decreasing the 
number of pops, calcium also functions in increasing the number of two- 
cavity fruit formed by the large seeded varieties. They suggested that 
calcium exerts this favorable effect by preventing abortion of the ferti- 
lized ovules which apparently occurs at a very early stage of fruit de- 
velopment before shell enlargement has begun. Brady, Nelson and Reed 
(15) have further indicated that calcium may increase the percentage of 
pegs which make shells. 

As early as 1911 Duggar and Funchess (50) reported highly profit- 
able increases in peanut yields from the use of lime in Alabama. In recent 
tests on Alabama soils which were relatively low in calcium and which 
had been subjected to intensive cultivation, Rogers (95) obtained very 
marked responses from the use of lime. Increasing the calcium level of 
the soil from approximately 400 pounds per acre of CaCOg, equivalent to 
800 or 900 pounds by the application of lime, resulted in a five-fold in- 
crease in yield of Spanish peanuts. Rogers reported that on soils low in 
calcium, additions of lime up to 3,000 pounds gave marked increases in 
yield of both Spanish and runner-type peanuts. 

The results of a 10-year experiment conducted on a Tifton sandy loam 
by the Georgia Coastal Plain Experiment Station (13) showed that lime 
applied at the rate of 500 and 1,000 pounds per acre was of little value 
for peanuts. It was reported that the test "followed a general rotation in 
which other crops were. fairly well fertilized." However, there is no indi- 
cation of the calcium level of the unlimed soil. 

In field experiments conducted in Uganda, East Africa, peanuts have 
shown no response in yields to amendments of lime (60). Workers in 
Senegal have reported a 35-percent increase in peanut yields from appli- 
cations of 3 tons of lime per acre (60). 

In a test of some 13 different varieties and strains of peanuts by 
McClelland (68), in Arkansas, increases of as much as 2,000 pounds of 
nuts and 3 tons of hay per acre were obtained with certain varieties from 
the application of 1,056 pounds of crushed limestone. The average in- 
crease in yield from lime with all the varieties was 890 pounds of nuts 
and 1.03 tons of hay. 



138 THE PEANUT— THE UNPREDICTABLE LEGUME 

Numerous tests conducted in Virginia have emphasized the need for 
calcium in the production of large-seeded varieties of peanuts. Batten 
(29) has suggested that an adequate calcium level may be maintained by 
applying 1,500 to 1,800 pounds of ground limestone per acre or its equiva- 
lent to peanut soils every 3 or 4 years. Large applications at one time 
have been found to be harmful. It was suggested that the pH be main- 
tained between 5.8 and 6.2, and on the lighter soils the pH should never 
exceed 6.4. Batten reports that gypsum is almost universally used where 
the large-seeded peanuts are grown. However, this material has not been 
found to increase yields where lime has been used to maintain a "suit- 
able" soil reaction. 

The results of other experiments at different localities in the United 
States are varied. The response or lack of response may be explained 
in most cases by the mineralogical nature of the soil and the level of 
calcium. Generally, however, the soils on which peanuts are grown are 
relatively low in calcium and unless large amoijnts of lime have been 
applied in recent years some benefit may be expected from the use of this 
element. 

Sources of Calcium 

There is considerable evidence that peanuts will make satisfactory 
growth on relatively acid soils provided the calcium needs of the plant 
are satisfied. Thus, the primary consideration in the use of lime or other 
calcium-bearing materials for peanuts is to furnish an adequate supply 
of the nutrient calcium. The three calcium-bearing materials most com- 
monly used for peanuts are gypsum or landplaster (CaS04.2H20), cal- 
citic limestone and dolomitic limestone. Numerous tests have been made 
to determine the most satisfactory of these materials for peanuts. 

Little differences in peanut yields were observed at two locations in 
Mississippi (14) from the use of 400 pounds of gypsum under the seed, 
400 pounds of gypsum dusted on the plants, and 400 pounds of dolomite. 
However, little response was obtained from any of these treatments. In 
other experiments 1,200 pounds of lime yielded somewhat better than 
400 pounds of gypsum. 

Comparable yields of large-seeded peanuts were obtained in experi- 
ments in Virginia (30) with 500 pounds of gypsum, 2,000 pounds of 
burnt shells, and 4,000 pounds of ground shells. Other studies (32) in- 
dicated that ground oyster shells and dolomitic limestone were of equal 
value for peanuts. 

Rogers (95) studied the effect of ten sources of calcium upon the yield 



SOIL FERTILITY 



139 



of Spanish and runner peanuts grown in a rotation with vetch. The lime 
materials were applied broadcast at two rates, 1,500 and 3,000 pounds 
per acre, to a Norfolk sand. The results are shown in table 4. All of the 
calcium sources were found to be approximately equal in value except the 
calcium silicate slag which gave profitable increases over no lime but was 
inferior to other liming materials. Dolomitic limestone was found to be 

Table 4. — Peanut Yields as Affected by Kinds and Rates of Lime and Growth 
OF Vetch as a Green Manure Crop, Auburn, Alabama.* (95) 



Lime treatment 



Kind of lime 



Pounds 

per acre 

applied, 

1941 



Soil 
pH 

Sept. 

1945 



Yields of 
vetch 
turned 
under, 
pounds 
per acre 
1942-45 



Yields of 

Spanish 

peanuts, 

pounds per 

acre 

1943-45 



None 

Calcic limestone (Av. of 3 sources) . 

Dolomitic limestone (Av. of 3 
sources) 

Oyster shell 

Paper mill waste 

Blast furnace slag 

T.V.A. Ca-silicate slag 



1,500 
3,000 



1,500 
3,000 

1,500 
3,000 

1,500 
3,000 

1,500 
3,000 

1,500 
3,000 



5.3 

5.3 

5.5 



5.3 
5.6 

5.3 
5.6 

5.3 

5.7 

5.2 
5.6 

5.4 
5.6 



5,766 

14,720 
16,701 



16,073 
18,615 

16,874 
16,894 

18,743 
16,757 

13,243 
15,694 

14,822 
15,341 



1,093 

2,073 
2,307 



2,165 
2,633 

1,871 
2,242 

2,203 

2,415 

1,666 
2,198 

1,978 
1,732 



♦Maximum response to lime obtained in these tests in small plots by turning under vetch each year 
as a green manure crop, close spacing of plants, and fertilizing both vetch and peanut crop with 300 
pounds per acre of 0-14-10. Peanuts were planted and dug each year from these plots on Norfolk loamy 
sand since 1942. (The 1942 crop was lost after harvesting.) 



superior to calcitic lime oh an intensively cropped Norfolk sand but was 
not significantly better in larger-scale field tests on sandy loam soils. 

Experiments were conducted in North Carolina (47) to compare the 
relative values of dolomitic and calcitic limestone and gypsum, applied at 
diflferent dates and in different manners. The results are shown in table 
5. Calcitic limestone was found to be distinctly superior to dolomitic 
limestone, regardless of the time of application. Furthermore, almost 
twice as much dolomite had to be applied' to furnish the same amount of 



140 



THE PEANUT— THE UNPREDICTABLE LEGUME 



calcium as was supplied by calcitic lime. Pure magnesium carbonate was 
found to decrease the yields somewhat. At one location 640 pounds of 
gypsum appeared to be superior to calcitic lime while at another the lime 
resulted in higher yields. 

It is obviously very difficult to evaluate the effectiveness of various 
sources of calcium. In many instances arbitrary comparisons have been 

Table 5. — Yield of Virginia Bunch Peanuts as Affected by Different Calcium 
AND Magnesium Carriers. Reported by North Carolina Agricultural 
Experiment Station 1944. (47) 



Treatment 


ToS 


upply 


Yield — Pounds per acre 


Method and time of application of 






Location 


materials and rate in pounds per acre 


Calcium 


Magnesium 


I* 


//** 




Pounds 


Pounds 








CaO 


MgO 








per Acre 


per Acre 


74 




No treatment 


— 


— 


889 


Broadcast February IS 




Dolomitic limestone 1974 


600 


430 


928 


1515 


Calcitic limestone 1074 


600 


— 


1174 


2008 


Dolomitic limestone 1316 


400 


286 


533 


1541 


In row at planting — April 25 










Dolomitic limestone 658 


200 


— 


415 


843 


On row at emergence — May 14 










Landplaster 640 


200 


— 


1644 


1468 


Burnt lime 200 


200 


— 


808 


1289 


Dolomitic limestone 658 


200 


143 


570 


1011 


Calcitic limestone 358 


200 


— 


907 


1618 


Magnesium carbonate 300 


— 


143 


47 


694 


On foliage — July 7 










Landplaster 600 


200 


— 


1209 


1907 


L.S.D. .05 


— 




233 
313 


244 


.01 


329 







♦Norfolk sand; pH = 5.0; exchangeable soil calcium = 0.38. 
**Norfolk loamy sand; pH = 5.0; exchangeable soil calcium = 0.46. 

made between two or more calcium-bearing substances with little effort 
made to place the materials on a comparable basis . . . that is, to add 
equivalent amounts of calcium or to use quantities of liming materials of 
equal neutralizing power. Furthermore, many of the calcium materials 
are carriers of other elements which may also influence the experimental 
results. Despite these difficulties, from the existing knowledge of the use 
of liming materials and of the calcium needs of peanuts, it should be pes- 



SOIL FERTILITY 



141 



sible to predict the most effective means of supplying calcium to this 
crop. 

On most soils it would appear to be better to meet the calcium needs 
of peanuts by liming materials rather than through the use of neutral cal- 
cium salts such as gypsum. With the possible exception of tobacco, most 
of the crops which might be grown in rotation with peanuts would benefit 
from the use of lime on the more acid soils. Furthermore, on very acid 
soils (below pH 5.0) peanuts themselves may respond more to liming 
materials than to additions of neutral calcium salts. For example, the 




Courtesy North Carolina Agricultural Experiment Station (81) 

Figure 4. — The response of Virginia Bunch peanuts to additions of one ton of 
dolomitic limestone. The stunted, light colored plants, were growing on soil 
at a pH of 4.7 and with 0.46 m.e. of exchangeable calcium. 

response to lime may be evidenced by a darker, greener vegetation and an 
increase in plant size as shown in figure 4. The stunted, light-colored 
condition of peanuts on very acid soils is due in part to a deficiency of 
nitrogen, resulting from a reduction in activity of nitrogen-fixing micro- 
organisms. Mann (69) has reported that the addition of lime to virgin 
Norfolk and Coxville soils (pH 5.3 and 4.5) resulted in a large increase 
in nodulation of peanuts while gypsum reduced the nodulation. In view of 
recent work (53, 77, 97, 113) with other legumes, the poor growth of 
peanuts on very acid soil may be due in part to a toxicity of such elements 
as manganese, iron and aluminum. Too, there is evidence (28, 39, 78) 



142 THE PEANUT— THE UNPREDICTABLE LEGUME 

that with certain plants calcium is not absorbed as readily in acid media 
as in those of a higher pH. 

Peanuts are especially heavy "feeders" of potassium and the plant may 
absorb considerably more of this element than is needed. Certainly it 
would be desirable to reduce this luxury consumption of potash if the 
yields were not adversely affected. There is considerable evidence (86, 
87, 93, 113) that the addition of lime to soils will result in a decreased 
absorption of potash by the plant. On the other hand, gypsum may in- 
crease the uptake of K (93, 113). The differential effect of the two ma- 
terials upon potash absorption provides another point in favor of the use 
of limestone rather than gypsum for peanuts. 

On soils aSjsfextremely low-exchange capacity, it may be necessary to 
■'apply a soluble source of calcium in addition to lime in order to supply 
adequate amounts of calcium. 

Recent fundamental studies (37, 46) have emphasized the specific 
need of the peanut for calcium and have shown that cations of a similar 
nature, such as magnesium, cannot be effectively substituted for calcium. 
If the primary objective in using lime for peanuts is to supply the nutrient 
calcium, it should be desirable to use a material which would be most ef- 
fective in meeting that need. When the soil pH is increased beyond a cer- 
tain point by liming, certain minor-element deficiencies may be en- 
countered. Thus there is an obvious- limit to the amount of lime which 
may be safely used. Yet dolomitic Hmestone is used almost exclusively in 
some peanut-producing regions, and less than one-half the amount of cal- 
cium is supplied by this material in liming a soil to a given pH as would 
be added were calcitic limestone used. Therefore, from the standpoint of 
meeting the calcium requirements of peanuts, it should be more desirable 
to use a form of calcitic limestone rather than one high in magnesium. 

Some soils used for the production of peanuts are low in magnesium, 
and the superiority of dolomitic limestone observed in certain experi- 
ments has undoubtedly been due to a magnesium response. However, the 
magnesium requirement of peanuts is relatively low and, on soils deficient 
in this element, it might be desirable to supply the needed magnesium in 
the fertilizer or to use a mixture of calcitic and dolomitic limestone. If 
such a mixture were used, it would appear to be desirable to keep the 
ratio of Ca to Mg in the liming material relatively high. 

Placement of Calcium 

Recent studies (40) have shown that much of the calcium absorbed 
by the peanut roots is immobilized in the leaves and stems, and insuf- 



SOIL FERTILITY 



143 



ficient quantities are normally translocated to the developing gynophores 
to insure well-developed kernels. The studies have further shown that 
calcium may be absorbed directly by the developing pods and have 
indicated that for proper kernel development it is very important that an 
adequate supply of calcium be present in the zone in which the fruit are 
formed. 

By using a technique in which the runners on one side of the plant 
could "peg-down" in one medium and the fruit on the other side of the 
plant could develop in a dififerent medium, Brady (36) was able to 




Figure 5. — The influence of gypsum upon the formation of well developed pods. The 
fruit on the left developed in a media supplied with a calcium sulfate solution, 
while those on the right were supplied with distilled water only. Brady (36) . 

demonstrate quite clearly the importance of proper placement of calcium. 
Figure 5 shows that an abundance of well-developed pods were formed on 
the side of the plant which had received calcium while relatively few 
healthy fruit were produced on the other side in a medium which had not 
been supplied directly with calcium. This work clearly shows that calcium 
is not readily translocated from one part of the plant to the other. Other 
data (table 6) reported by Colwell and Brady (45) demonstrate the im- 
portance of proper placement in the use of calcium-bearing materials for 
peanuts in a low-calcium environment. Gypsum supplied to the rooting 
zone did not adequately meet the demands of the developing fruit ; how- 
ever, large increases in shelling percentage and yield were observed 
when the gypsum was applied to the fruiting medium. Obviously, for 



144 



THE PEANUT— THE UNPREDICTABLE LEGUME 



satisfactory kernel development, it is essential that calcium be supplied to 
the zone in which fruit are being formed. 

The best method of applying gypsum to peanuts appears to be that of 
dusting the material on the plant at the early flowering stage. This rela- 
tively soluble source of calcium falls around the plant in the zone of pod 
formation and is present at the time when the need for calcium is the 
greatest. It is essential that the gypsum be well distributed throughout the 
zone of fruit formation. Since there is little residual efifect of normal 
applications of gypsum (300 to 600 pounds per acre), it is necessary to 
make annual additions of this material. 

Table 6. — Effect of Placement of Gypsum on Yield and Quality of Peanuts 
ON Norfolk Fine Sandy Loam, Deep Phase, in 1942». (45) 



Gypsum 
application^ 


Total 

fruit 

examined 


Percentage 

fruit 


True 
shell- 
ing 
Per- 
cent 


Corrected 
Yield 

Pounds 
per 
Acre 


Soil analysis 


Well 
filled 


Half 
"pops" 




None 


2,057 
2,915 
2,593 


9 
19 
49 

6.8 
9.1 


12 
24 
15 


24.9 
40.5 
52.9 

7.3 
9.9 


364 

878 

1,595 

310 
417 


pH =6.1 
Ex. Cap. = 2.10 
Ex. Ca = 0.21 
Percent Ca 

Sat. = 10 
Ex. Mg = 0.16 
Ex. K =0.06 
Percent O.M. = 0.8 
P, p.p.m. = 30 


Rooting medium. 
Fruiting medium 

L.S.D. (.05).... 
L.S.D. (.01).... 



* Four replications 

•> Rate = 400 pounds per acre. 

As shown in table 5, broadcast applications of lime may be as effective 
as gypsum in meeting the calcium requirements of peanuts. However, 
these and other data (18, 37, 45) generally indicated that lime applied in 
the row at planting may be inferior to gypsum. A satisfactory plan might 
be one in which 1,000 to 1,500 pounds of lime are applied broadcast to 
the peanuts every 2 to 4 years, the exact amounts and frequency of ap- 
plications being governed by soil characteristics. It would appear to be 
best to broadcast the lime after the land had been turned but before the 
peanuts are planted. By so doing, more of the calcium is concentrated in 
the surface layer and hence should be more effective in supplying the 
needs of the developing pods. By applying relatively small amounts of 
lime in this manner immediately prior to peanuts in the rotation, it might 
be possible to maintain an adequate supply of calcium without increasing 
the pH beyond the level where certain minor-element deficiencies are en- 
countered. 



SOIL FERTILITY 



145 



Effects of Soil Properties on Calcium Requirements 

Several studies have indicated that the response of peanuts to calcium 
is governed to a large extent by certain soil properties. Attempts have 
been made to correlate the level of exchangeable calcium in soils with 
response to lime additions. Rogers (95) found that the response of pea- 
nuts to lime was related to the exchangeable calcium level of the soil and 





110 


o 


100 


o 




K 


90 




Q 


n 


_i 


_i 


u 80 


UJ 


> 


V 






1- /u 


t- 


o 


s 


q! 60 


Ql 






Q 50 


U 


tij ^"^ 


u 

5 


i40 




_l 


_l 




Z 


30 


_> 






20 



10 




DATA FROM COLWCLL ANO 

BRADY 

DATA FROM ROCERS 



CHECK YIELDS AS PER CENT OF 
THOSE OBTAIMEO WITH CALCIUM 



X 



-L 



J_ 



X 



d. 



J L 



Q2 0.4 06 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 

M.E. Ca per 100 GRAMS OF SOIL 

Figure 6. — The relationship between lime response and the level of ex- 
changeable calcium in the soil. Work by Col well and Brady (45) was 
conducted on Norfolk soils in North Carolina while data by Rogers 
(95) was obtained from work with Norfolk soils in Alabama. 

indicated that the critical level of exchangeable calcium for peanuts on 
Norfolk soils in Alabama was between 0.6 and 0.8 m.e. per 100 grams of 
soil. Colwell and Brady (45) also observed a correlation between the 
exchangeable calcium level of soils in North Carolina and the response 
of peanuts to additions of lime. The relationships between the lime re- 
sponse and exchangeable calcium level as reported by Rogers and by 
Colwell and Brady are shown in figure 6. It is interesting to note the dif- 
ferences in the data obtained by investigators in the two States. Little re- 
sponse resulted from liming soils in Alabama which contained more than 



146 THE PEANUT— THE UNPREDICTABLE LEGUME 

0.7 m.e. of calcium per 100 grams. However, lime response was observed 
on North Carolina soils with calcium levels up to approximately 1.4 m.e. 
Two factors may have contributed largely to these differences: First, 
small-seeded varieties of peanuts were grown in Alabama while the large- 
seeded types were used in the work in North Carolina. It has been sug- 
gested that large-seeded peanuts have a greater need for calcium than 
the small-seeded type. Second, the peanut soils in Alabama are generally 
of a lower exchange capacity than those used in North Carolina. The 
availability of a given amount of exchangeable calcium might be ex- 
pected to increase with a decrease in the base exchange capacity of the 
soil. 

Rogers (95) pointed out that lime response was more closely corre- 
lated with the exchangeable calcium level than with percentage calcium 
saturation or with calcium soluble in one-tenth normal hydrochloric acid. 
Colwell and Brady also found a better correlation between response to 
calcium additions and exchangeable calcium levels than with percentage 
calcium saturation of the soil. 

Recent investigations at the North Carolina Experiment Station (17, 
18, 72, 73) have revealed some very interesting relations between soil 
properties and the response of peanuts to calcium. Mehlich and Colwell 
(72) studied the absorption of calcium by peanuts as affected by the type 
of soil colloid using different levels of exchangeable calcium. These 
workers used relatively pure colloidal materials of the 1 :1 and 2 :1 lattice 
types and varied the adsorption capacity by diluting the materials with 
quartz sand. With equal concentrations of calcium in sand-clay systems 
more calcium was absorbed from the kaolonite or 1 :1 type mineral than 
from the 2 : 1 type bentonite. The effect of type of clay on calcium avail- 
ability was also evidenced by the quality of the fruit produced (figure 
7) . A high percentage of filled pods was produced on kaolonitic colloids 
even at relatively low calcium levels. In the bentonite systems larger 
amounts of calcium were required to produce fruit of similar quality. 
These workers observed that the uptake of calcium from kaolonite 
systems was more directly related to the total calcium present than to the 
degree of saturation. In the systems of 2 :1 type mineral the absorption of 
calcium was found to be more directly related to the percentage calcium 
saturation than to the total amount present. 

In a later investigation Mehlich and Reed (73) studied the behavior 
of peanuts grown in systems in which the cation-adsorption capacity was 
due to both organic and mineral colloids. Kaolonite, bentonite and muck 
were used to prepare colloid-sand systems with different cation-ad- 



SOIL FERTILITY 



147 



sorption capacities, different exchangeable calcium levels and different 
percentage calcium saturations of the exchange complex. It was found 
that at any given level of exchangeable calcium, the quality of fruit was 
lower when produced in bentonite or muck. At any given cation-ad- 
sorption capacity the percentage of well-filled pods increased with an in- 
creasing degree of calcium saturation. Yet, when the percentage calcium 
saturations were of the same order the higher calcium levels produced 
the better quality of fruit. These workers pointed out that both the per- 



^100 

bJ 

O 90 

q: 
uj 80 

CL 



I 

O 

txJ 



in 



70 
60 
50 

z 20 

<; 

% 10 



B 





T --#— - 

« 


• 

'KAOLIN 2,4 


M.E. 


^;p^^ 


1 

1 
• 


/KAOLIN 0.8 M.E. 

/ / BENTONITE 


2.4 


M.E. 


-9' 

1 

1 


/ ^ 








0' 

■J 


/bentonite 


0.8 M.E, 






1 


1 1 1 


1 1 1 


1 


1 1 



02 OA Oj6 08 1.0 1.2 1.4 1.6 1.8 2.0 22 2A 
M.E. Ca per 100 GM. — COLLOID -SAND MIXTURE 

Figure 7. — Percentage ovarian cavities of peanuts filled as afifected by type 
of colloid, cation-adsorption capacity and calcium level. Mehlich and 
Col well (72)_. 

centage calcium saturation and calcium level would have to be considered 
in determining the need for calcium in peanut soils. 

A comparison of the relative availability of calcium in soils of dif- 
ferent types of colloids is shown in figure 8. Using the percentage of filled 
nuts as a criterion of calcium availability, it is evident that a small amount 
of calcium is much less effective in a soil high in organic colloids than in a 
soil in which the cation-adsorption capacity arises from kaolonitic-type 
minerals. Furthermore, it is evident that greater amounts of calcium 



148 



THE PEANUT— THE UNPREDICTABLE LEGUME 



would be needed for the production of good quality peanuts in soils high 
in organic matter or in those containing a large percentage of 2 : 1 type 
miijerals. 

Studies by Mehlich and Reed (73) of a number of surface soils from 
the Coastal Plain areas of North Carolina have indicated that the cation- 
adsorption capacity due to organic fraction of the colloids varied between 
8 and 70 percent of the total. Such differences in the nature of the col- 



type of colloid 
Okaolin 

^bentonite 

■ organic 



(O 



> 

< 
(J 



b2 



uu 




c 


80 


- 




60 


- 


^' . 


40 






20 


- 


i -• 







'■A 



m 

m 
1 






a 



0.38 M. E. 






1.30 M. E. 



2.40 M. E. 



EXCHANGEABLE CALCIUM 
CATION -ADSORPTION CAPACITY 2.4 M. E. 

Figure 8. — The effect of the type of soil colloid on peanut fruit quality at different 
levels of exchangeable calcium. The percentage of filled cavities may be taken 
as a relative index of the calcium availability in the different sand-colloid 
systems (94). 



loidal material in peanut soils could well explain why soils containing 
equal amounts of exchangeable calcium do not respond in a like manner to 
additions of calcium materials. Apparently the response of peanuts to 
amendments of calcium is influenced greatly by the type of soil colloid 
and the percentage calcium saturation as well as by the level of exchange- 
able calcium. 

MINOR ELEMENTS 

Experiments conducted by several of the southeastern experiment 
stations have failed to show any widespread response of peanuts to ad- 
ditions of different "secondary" and "minor" elements. 

There is some evidence that certain minor-element deficiencies may oc- 



SOIL FERTILITY 149 

cur on soils which have been heavily limed. Batten (29) reported that 
peanut yields were reduced by applications of 2,700 pounds of lime, and 
recently Shear and Batten (99) initiated a study to determine the cause 
of poor growth and a chlorotic condition of peatiuts grown on sandy soils 
which had been heavily limed. These workers found that the yields of 
peanuts on heavily limed soils were increased, by the addition of 20 
pounds per acre of MnSOi applied as a side dressing in June or by a 
broadcast application of 300 pounds of sulfur before planting. The yield 
increases were found to be associated with an increase in manganese up- 
take in both cases. The addition of manganese was found to increase the 
yield of nuts over the entire pH range studied; however, the beneficial 
effect was most pronounced at the higher pH levels (approximately 6.9). 
The shelling percentage was found to be decreased by manganese due to 
the fact that the growth period was extended, resulting in more immature 
nuts at harvest time. 

Nelson (81), in North Carolina, has also observed "overliming in- 
jury" in peanuts, apparently resulting from a deficiency of manganese. 
An example of such injury is shown in figure 9. 

Workers ( 1 ) at the Alabama Experiment Station report that appli- 
cations of diiTerent combinations of 10 pounds of zinc sulfate, 5 pounds of 
borax, 25 pounds of manganese sulfate, and 5 pounds of copper sulfate 
per acre to a Norfolk sandy loam failed to increase the yield of Spanish 
peanuts. 

The following elements were added to a Norfolk sandy loam in an 
experiment conducted by the Georgia Experiment Station (6) : Sulfur, 
40 pounds; manganese, 25 pounds; magnesium, 75 pounds; zinc, 10 
pounds ; copper, 10 pounds ; boron, 5 pounds*. None of these materials 
applied alone or in combination with 500 pounds of limestone gave an in- 
crease in yield of nuts or hay. In another experiment conducted in a 
"sulfur-deficient area," Futral (6) reported that sulfate of ammonia was 
superior to nitrate of soda for Spanish peanuts and suggested that this 
superiority was due to a sulfur response. 

A summary of experiments conducted on several soils in north 
Florida (5) shows little effect of additions to peanuts of a minor element- 
mixture containing 10 pounds of copper sulfate ; 10 pounds of magnesium 
sulfate ; 5 pounds of zinc sulfate ; and 5 pounds of borax. Harris (57) has 
recently reported that peanuts grown on an Arredondo loamy fine sand 
in Florida developed abnormal characteristics which were corrected by 

*The rates reported in this experiment were probably for the salt containing the element rather 
than the amount of the element itself, a possible exception being sulfur. 



150 



THE PEANUT— THE UNPREDICTABLE LEGUME 




^-.^*mf: 



■ife- ^a^ - 



■*»■ 



Conrtcsy North Carolina Agricultural EA-pcrimcut Station (81) 

Figure 9. — "Overliming injury" with peanuts, resulting apparently from a deficiency 
of manganese. The stunted, chlorotic plants in the center of the picture were 
growing on soil at pH 7.7 while the soil in the surrounding area was at pH 5.9. 
Such injury has been observed on soils as low as pH 6.4. 

additions of copper to the soil. Applications of 10 pounds per acre of 
cupric chloride to the soil were found to increase the yield of both nuts and 
foliage and improved the grade quality of peanuts. 

Collins and Morris (43) report that tests with iron, magnesium, 
copper, borax, manganese and zinc in 12 exjperiments in North Carolina 
over a 3-year period show little evidence that these elements were limit- 
ing factors in the production of peanuts. 

Piland, Ireland and Reisenauer (88) studied the effect of additions 
of 5 pounds of borax on the quality of peanuts at 17 different locations in 
North Carolina. The average of the results showed that boron had a 
slight tendency to reduce the shelling percentage. However, the per- 
centage of large nuts was increased significantly by the addition of borax. 

Sommer and associates (101, 102) in greenhouse studies with several 



SOIL FERTILITY 151 

Alabama soils observed marked increases in nut production from the use 
of magnesium. However, the soils had been subjected to very intensive 
cultivation prior to planting peanuts, and the responses were undoubtedly 
exaggerated because of .abnormally low magnesium levels. These workers 
reported that little benefit was obtained from the addition of minor ele- 
ments to peanuts. 

VARIETAL DIFFERENCES IN RESPONSE 
TO FERTILIZATION 

Many studies have" indicated that peanut varieties exhibit marked 
differences in response to fertilization. Several workers (10, 106) have 
suggested that the so-called small-seeded types were more responsive to 
additions of N, P and K, whereas the large-seeded types might be ex- 
pected to respond more to Ca amendments. However, there appear to be 
decided differences in the nutritional requirements of varieties within 
either of the different major types. Such differences might limit broad 
generalizations regarding the response of any given type of peanut to 
fertilization. 

McClelland (68), in Arkansas, reported the results of experiments 
in which a number of different varieties and strains of the major types 
of nuts were grown with and without additions of limestone. The results 
are shown in table 7. Strains of Spanish peanuts were found to differ 
greatly in response to lime. Greater increases in yields of hay and nuts 
were obtained with improved Spanish and Spanish Selection than with 
any of the small runner or large-seeded types. The yield of Virginia 
Jumbo, a large-seeded type, was initially very high and was slightly re- 
duced by the lime. 

The 5-year average results of an experiment conducted on a Norfolk 
sand at the Florida Experiment Station (65) are shown in table 8. 
Several different varieties and strains of both the large- and small-seeded 
type peanuts were grown with and without additions of 600 pounds of 
gypsum. The average results show little response of small-seeded varieties 
or of Virginia Bunch, a large-seeded variety, to this calcium-bearing ma- 
terial. The yields of Jumbo variety were increased by adding gypsum, 
while this material tended to decrease the yields of Virginia Runner, also 
a large-seeded type. Therefore, although one of the large-seeded varieties 
appeared to benefit from the gypsum, it is not possible to conclude from 
this experiment that, as a group, the large-seeded peanuts were any more 
responsive to amendments of calcium than were the small-seeded 
varieties. 



152 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 7. — Effect of Lime upon Yields of Several Varieties of Peanuts. 
Arkansas Experiment Station,"* 1940. (68) 



Variety and 
treatment 


No Lime 


Lim^ 


Gain with Lime' 


Peanuts 
per acre 


Ha-^ 
per acre 


Peanuts 
per acre 


Hay 
per acre 


Peanuts 
per acre 


Hay 
per acre 




Pounds 


Tons 


Pounds 


Tons 


Pounds 


Tons 


Spanish 


3,353 
2,508 
2,429 
2,429 
3,036 
2,561 
1,716 
3,300 
2,112 
528 
4,488 
2,006 


3.76 
2.90 
2.71 
2.71 
3.37 
2.84 
2.11 
4.22 
2.51 
.79 
5.28 
2.77 


3,564 
4, 462 
4,488 
3,221 
3,300 
2,851 
2,376 
3,828 
3,168 
1,584 
4,224 
2,719 


4.29 
5.94 
5.28 
3.70 
3.63 
3.23 
3.04 
5.08 
3.96 
2.05 
5.02 
3.43 


211 

1,954 

2;059 

792 

264 

290 

660 

528 

1,056 

1,056 

-264 

713 

f 


0.53 


Improved Spanish 

Spanish Selection .... 

Red Spanish (1) 

Red Spanish (2) 

Valencia 

Tennessee Red (1) . . . 
Tennessee Red (2) . . . 

Virginia Red 

White Virginia 

Virginia Jumbo 


3.04 
2.57 
0.99 
0.26 
0.39 
0.93 
0.86 
1.45 
1.26 
-.26 
0.66 







* Applied in the row before planting at the rate of 880 pounds of air-slacked lime per acre. 
•> Hay yields include weights of nuts. 

• No information was presented relative to the experimental design, replications, or the magnitude 
of differences which might be considered to be significant. 

<> Bolivar silt loam. pH = S.42-5.65. 



Table 8. — Effect of Gypsum on Yield of Several Peanut Varieties. Norfolk 
Sand. Florida Agricultural Experiment Station. (65) 



Variety 



5 Year Avefi J!>23/24/25/26/2S 



Gypsum^ 



No 
Gypsum 



Increase Over 
No Gypsum 



Pounds 
per Acre 



Pdunds 
per Acre 



Pounds 
per Acre 



Spanish (Florida) . . . 
Spanish (Improved) 

Valencia 

Va. Bunch 

Va. Runner" 

Jumbo 

Fla. Runner 



661 
618 
591 
994 
801 
1,100 
1,047 



647 
580 
552 
930 
950 
786 
995 



14 
38 
39 
64 
-149 
314 
52 



■ Gypsum applied as top dressing at the rate of 600 i>ounds per acre as peanuts started to bloom, 
k The 1927 peanut crop was destroyed by rodents. Continuous peanuts on the same plots from 1923 
to 1928. All plots planted to oats in fall of year and turned in spring several weeks before peanut planting. 
The Virginia Runner was not in the test in 1923 and consequently has a 4-year average. 



SOIL FERTILITY 



153 



Stokes and Camp (104), working in Florida, have reported that 
gypsum gave profitable increases in yields of Florida runner and a Jumbo 
variety, but not of the Spanish, Valencia and Virginia Bunch varieties. 

Experiments conducted at several locations by workers at the North 
Carolina Station (46) show considerable differences in response of the 
large- and small-seeded type peanuts to additions of lime and gypsum. 
On soils extremely low in calcium, the Virginia Bunch variety, a large- 
seeded type, was found to respond more to additions of gypsum than a 
small runner and White Spanish varieties. On soils high in calcium the 
response was quite erratic and no general trends were observed. 

A detailed study by Middleton, et al. (74) of the behavior of four 
varieties of peanuts as affected by calcium and potassium variables re- 
veals some interesting variety-fertility interrelations. Some of the results 
of this study are shown in figure 10. It is evident that the relative behavior 
of the four varieties depended upon the fertilizer treatment. For example : 
Without treatment the Spanish varieties yielded highest and the Virginia 
Bunch yielded lowest. However, when all varieties received gypsum, the 
yield of Virginia Bunch was the highest. The authors concluded that the 

YIELD EXPRESSED IN POUNDS PER ACRE 
SHELLING 60 PER CENT 



GK 



356 






i 

te 



L.SDC05) ;§| 

11 



VIRGINIA 
BUNCH 



G = 400 POUNDS OF GYPSUM 

GK = 400 POUNDS OF GYPSUM PLUS 45 
POUNDS OF KgO 



N. C. 
RUNNER 



SPANISH 
2 B 



GK 




WHITE 
SPANISH 



Figure 10. — The relative yields of four varieties of peanuts grown with and without 
amendments of gypsum and potash. Gypsum applied to foliage at early bloom- 
ing; potash applied as top dressing at emergence. Soil, Norfolk sand; pH = 
4.6; 0.54 m.e. exchangeable calcium; 0.04 m.e. exchangeable K. Source: Middle- 
ton, Colwell, Brady, and Schultz (74). 



154 THE PEANUT— THE UNPREDICTABLE LEGUME 

Spanish varieties might be better suited to soils low in calcium than tne 
Virginia Bunch unless proper steps were taken to supply adequate 
calcium. 

These workers at the North Carolina Station also point out that from 
one experimental location to another the effects of the fertilizer treat- 
ment on a particular variety were more consistent than the relative yields 
of the four varieties receiving the treatment. It was suggested that even 
when the calcium and potassium requirements were met some other 
factor apparently influenced the yield of one variety more than another. 
In view of the fact that the Spanish variety performed relatively better 
on soils with high organic-matter levels, it was suggested that there 
might have been a differential response to nitrogen. 

Middleton and Farrior (75) reported that the Virginia Bunch 
variety performed better on some North Carolina soils than did the 
Jumbo Runner, whereas the reverse was true on other soils. These 
workers also observed that the large-seeded varieties appeared to respond 
more to the use of gypsum than did the small-seeded types. 

The results of experiments conducted on a Norfolk loamy fine sand 
in Georgia are generally in agreement with the findings of the North 
Carolina workers. Investigators (6) at the Georgia Station found that a 
Spanish variety showed little response to additions of lime or gypsum 
while the yields of Carolina Runner, Virginia Bunch and Virginia Run- 
ner were increased by both materials. Without calcium amendments, the 
Spanish variety yielded more than did either of the Virginia varieties. 
With additions of lime and gypsum the relative order was changed. 

Differences in response of varieties to applications of nitrogen are 
shown in table 3. Results of experiments conducted by the staff of the 
Alabama Experiment Station show that relatively large increases were 
obtained from additions of nitrogen to a Spanish variety, whereas the 
higher rates of nitrogen were of less value with a "runner" variety. Gore 
(55) in Georgia has also found the North Carolina Runner peanut to be 
less responsive to nitrogen amendments than a Spanish variety. 

At first glance some of the variety-fertility interaction data in the 
literature appear to be quite anomalous. Some of the experimental data 
would indicate that one type or variety is most responsive to a given nu- 
trient at one location and least responsive at another. It is quite possible 
that even though some of the older varieties used in experiments con- 
ducted at different locations were the same in name, they may have been 
distinctly unlike genetically. If such genetic differences did exist, it should 
not be surprising if the behavior were not the same in view of the marked 



' SOIL FERTILITY 155 

differences in lime response which have been observed with strains of 
the same variety (table 7). 

Some of the experimental evidence might suggest that the differences 
in response of varieties or types of peanuts to fertilization are, to a cer- 
tain extent, a function of seed size. Such may be the case, or the unequal 
response to fertilization may be due to other genetic differences not as- 
sociated with kernel size. At any rate, it is fallacious to attempt to classify 
all peanut varieties in two categories, a large-seeded group and a small- 
seeded group, because of the gradation in kernel size, with no sharp differ- 
entiation which would permit such broad groupings. Certainly the dif- 
ferences in seed size and behavior of peanut varieties within either of 
the so-called major-size groups would limit generalizations as to their re- 
sponsiveness to fertilization. 

Considering the differences in varietal response to fertilization, it 
is very evident that research programs in peanut breeding and soil fer- 
tility should be inseparable. In comparative tests of several varieties, it 
has been demonstrated that an apparently superior variety may be defi- 
nitely inferior under different environmental conditions. Therefore, in 
evaluating peanut varieties, it is essential that they be grown at different 
levels of soil fertility and under other variations in environmental con- 
ditions. The fact that many of the present peanut varieties appear to be 
relatively unresponsive to fertilization does not preclude the possibility 
that varieties may eventually be developed which would respond to 
fertilizer amendments much in the same manner as do many other crops. 

ROTATION AND MANAGEMENT PRACTICES AND THE 
MAINTENANCE OF SOIL FERTILITY 

Several factors combine to make the problem of maintaining the fer- 
tility of peanut soils especially acute. First, the native fertility of the soils 
used for growing peanuts is relatively low. Furthermore, peanuts remove 
relatively large amounts of certain nutrients from the soil with the normal 
systems of management in which both hay and nuts are harvested. Since 
peanuts have not been found to be as responsive to direct applications of 
fertilizer materials as are many other crops, there is a tendency to supply 
much less of certain nutrients than is removed from the soil by the crop. 
Considering these factors, the problem is resolved to one of determining the 
most effective and economical manner of obtaining high yields of peanuts 
and other crops grown in rotation with them and, at the same time, main- 
taining the fertility of the soil. 



156 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Continuous Cropping With Peanuts 

Farmers have long recognized the fact that it is not desirable to plant 
peanuts year after year on the same soil. The harmful effect of continuous 
cropping with peanuts was aptly illustrated in a study conducted at the 
Georgia Coastal Plain Experiment Station (table 9). In an experiment 
in which continuous peanuts were fertilized with different combinations 
of N, P and K it was found that with all fertilizer treatments there was a 
progressive decline in yields with each successive crop of peanuts. There 
was little effect of withholding nitrogen or phosphorus from the complete 

Table 9. — The Yields of Successive Crops of Peanuts Grown with and without 
Addition of Fertilizers. Georgia Coastal Plain Experiment Station (11). 



Treatment'' 




Yield un. 


helled nuts per acre 




1940 


1941 


1942 


1943 


1944 




pounds 


pounds 


pounds 


pounds 


pounds 


No fertilizer 


1407 
1645 
1744 
1628 
1701 


1259 
1585 
1647 
1410 
1603 


804 
1169 
1303 
1013 
1272 


663 
1088 
1125 

910 
1150 


488 


0-8-8 


1037 


3-0-8 


1106 


3-8-0 


531 


3-8-8 


1075 







» 500 pounds fertilizer per acre. 

fertilizer ; however, the yields were markedly reduced when no potassium 
was added. Apparently the lack of potash was the factor primarily re- 
sponsible for the poor yields on the nonfertilized soil. Perhaps the yields 
could have been maintained at higher levels on the plots receiving the 
complete fertilizer had more than 40 pounds of potash been applied. 

Work conducted at the Alabama Experiment Station (2) further 
demonstrates the harmful effect of planting peanuts continuously on the 
same soil. It was found that the yield of cotton planted after 7 successive 
years of peanuts was only 345 pounds despite the fact that the cotton 
received 600 pounds of 6-8-8 fertilizer. At the same time, plots which had 
been planted to continuous cotton during this period and fertilized with 
600 pounds of 6-8-4 yielded 1,269 pounds of seed cotton. Peanut yields 
apparently had begun to decline also after 6 years of continuous cropping 
with peanuts. 

It would indeed be difficult to maintain the fertility of peanut soils 
through such a program of continuous cropping and inadequate fertili- 
zation. There is no evidence, however, which would indicate that the 



SOIL FERTILITY 157 

productivity of peanut soils could not be maintained if sufficient ferti- 
lizers are supplied to compensate for the nutrients removed by the crop. 
Yet, such a program of continuous cropping and heavy fertilization would 
undoubtedly not be economical. Furthermore, even though the fertility 
could be maintained, it would not be advisable to make successive plant- 
ings of peanuts on the same land because of the likelihood of more severe 
disease and insect infestation. 

Crops Grown in Rotation With Peanuts 

A number of crops such as corn, cotton, tobacco, soybeans, potatoes, 
grain sorghum, truck crops, cereals and legumes are well suited for use 
in rotations with peanuts. While there is little information relative to ro- 
tation requirements, it is generally recommended that peanuts not be 
grown on the same soil more than once every 3 or 4 years. 

Beattie and Beattie (33) of the U. S. Department of Agriculture have 
suggested that peanut rotations should include at least two soil-building 
crops, one of which is a winter cover crop. Batten (30) considers the 
chief requirement of a peanut rotation to be that it should furnish a con- 
siderable amount of organic matter to be incorporated with the soil. Gore 
(54) at the Georgia Experiment Station reports that peanuts do espe- 
cially well following well-fertilized cotton, tobacco or truck crops. This 
investigator reports that the only objection to rotating cotton with pea- 
nuts is the tendency for Sclerotium rolfsii to be more severe. It was re- 
ported that growers also found considerable disease in peanuts following 
cowpeas. The North Carolina Station has recommended that peanuts 
should not follow soybeans on soils where Sclerotium rolfsii is present. 

The majority of the experimental work with peanuts indicates that 
little response may be expected from fertilizing peanuts if they are grown 
in rotation with other well-fertilized crops. The results from five rotation 
experiments conducted in North Carolina ( 19, 20) for a period of 6 years 
show that the application of 100 pounds of muriate of potash to cotton 
preceding peanuts resulted in as high peanut yields as did the application 
of SO pounds to each crop. Furthermore, the yields of cotton were in- 
creased upon receiving all of the potash. The result of these and other 
(16, 18, 100) experiments suggests that instead of fertilizing peanuts 
directly it would be better to use relatively large amounts of fertilizers 
with other crops in the rotation which would respond to the additional 
fertilizer. 

Experiments conducted by the Alabama Station (2) indicate that the 
normally recommended rates of fertilizing a crop such as cotton are inade- 



158 



THE PEANUT— THE UNPREDICTABLE LEGUME 



quate when the crop is grown in rotation with peanuts. The results of 
experiments, reported in table 10, show that when two crops of peanuts 
were harvested during a 7-year period in a corn, cotton, peanut rotation, 
the fertility of the soil was depleted to such extent that the cotton yields 
were approximately one-half of those obtained on soil which had been 
planted to continuous cotton. The injurious effect of the two harvested 
crops of peanuts was overcome somewhat by applying more potash to the 
cotton. 

Table 10. — The Influence of Peanuts in a Rotation with Cotton and Corn 
UPON THE Yields of Cotton. Alabama Agricultural Experiment Station (2). 



Year^ 


Yield of cotton 
in corn, cotton, 
peanut rotation'- 


Yield of cotton 
in corn, cotton, 
peanut rotation^ 


Yield of cotton 
in a continuous 
cotton rotation" 




Founds per acre 


Pounds per acre 


Pounds per acre 


1933 


1696 

1368 

652 


1622 
1298 
1075 


1406 


1936 


1366 


1939 


1269 







" Cotton fertilized with 600 pounds 6-8-4; corn and peanuts unfertilized. 

!> Cotton fertilized with 600 pounds 6-8-4 in 1933 and 1936; 600 pounds 6-8-12 applied to cotton in 
1936. Corn and peanuts unfertilized. 

" Cotton fertilized yearly with 600 pounds 6-8-4. 
^ The experiment was initiated in 1932. 



Legumes and Nonleguminous Cover Crops in Peanut Rotations 

Very little plant residue is returned to the soil from a crop of peanuts ; 
thus, as normally harvested, peanuts remove considerable quantities of 
inorganic nutrients. Furthermore, when peanuts are harvested the soil is 
left completely bare for several weeks during late summer and fall, pro- 
viding conditions favorable for the rapid oxidation of the soil organic 
matter. Certainly it would be difficult to maintain the productivity of 
peanut soils unless measures were taken to replenish the supply of organic 
matter. Green manure crops are well suited to peanut rotations and their 
use may help maintain an adequate level of organic matter in soils. 

Numerous experiments have been conducted to determine the effect 
of legumes and nonleguminous cover crops upon the yield of peanuts. 
Investigators at the Alabama Station ( 1 ) have studied the effect of vetch 
and oats upon the yield of continuous peanuts, and the results are re- 
ported in Table 11. These data show that the addition of phosphorus and 
potash to peanuts resulted in a 50-percent increase in yields. When vetch 
was grown and fertilized with P and K, the yields of peanuts were more 



SOIL FERTILITY 



159 



than doubled. Oats, unfertilized and turned under while green, increased 
the yields some 250 pounds. The addition of nitrogen to the oats resulted 
in a further increase in yield of 275 pounds, suggesting that part of the re- 
sponse to the vetch was due to the nitrogen supplied by the legume. 
Vetch appeared to have little influence on peanut yields when grown prior 
to cotton in a peanut, vetch, cotton rotation. 

Table 11. — The Effect of Green Manure Crops on the Yield of Spanish 
Peanuts. Experiments Conducted at Auburn, Alabama, on a Norfolk Sandy 

Loam Soil (1). 



Number Cropping System 


Fertilizer^ 


Yield of Peanuts 

pounds per acre 

4-year average 

1943-46 




None 
P-K 
P-K 
N-P-K 

None 

N 

P-K 
P-K 

P-K 

P-K 
P-K 


626 


2 Continuous peanuts 


985 


3 Continuous peanuts with vetch 

4 Continuous peanuts 


1364 
972 


5 Continuous peanuts with oats as 

green manure crop 


851 


6 Continuous peanuts with oats as 

green manure crop 


1121 






peanuts 


1094 


t«n- 








vetch 


1095 







• N = 36 pounds nitrogen from nitrate of soda. 
P-K = 300 pounds 0-14-10 per acre. 



Workers (15) in North Carolina have studied recently the efifect of 
several different cover crops upon the yields of peanuts in a cotton-peanut 
rotation. The results are shown in figure 11. The legumes were found to 
increase the yields of peanuts an average of 40 percent. It was concluded 
that the increase was not due to the nitrogen supplied by these crops since 
the yields of the "no-cover" plots were not affected by the addition of 
60 pounds of nitrogen. Yet, as seen in figure 11, ryegrass was not as efifec- 
tive as were the legumes. These investigators indicated that turning under 
large amounts of winter cover crops prevented packing and left the soil 
in better physical condition. Penetrometer measurements indicated that 
the soil in the vetch plots was more easily penetrated than in the "no- 



160 



THE PEANUT— THE UNPREDICTABLE LEGUME 



I600r 
u 
q: 
o 
< 

^ 1200 

I 
if) 

5 800|- 

z 
< 



O 400- 



_l 




WINTER COVER CROPS PRECEDING PEANUTS 

Courtesy North Carolina Agricultural Experiment Station (IS) 

Figure 11. — The effect of different winter cover crops upon the yield of Virginia 
Bunch peanuts. (3-year average). 

cover" plots. It is essential that peanut soils be in good physical condi- 
tion because the pegs must penetrate the surface soil in order for nuts to 
be formed. 

Effect of Methods of Harvesting Peanuts on Soil Depletion and 
Growth of Succeeding Crops 

A large percentage of the peanuts grow^n in the United States is har- 
vested for market by removing both nuts and vines from the soil. As dis- 
cussed previously, such a system of management is know^n to remove 
large quantities of nutrients and to lower the productivity of the soil. In 
some sections of the Southeast, the practice of harvesting the peanut crop 
by grazing hogs (hogging-off) is followed. With such a practice most of 
the nutrients are returned to the soil in the plant residues and animal 
manures. Peanuts handled in this manner may serve as a soil-building 
crop. 

Results of studies conducted at the Wiregrass Experiment Station in 
Alabama with different cropping systems including hogged and dug pea- 
nuts are shown in table 12. Peanuts planted continuously on the same 
soil, unfertilized and harvested by hogs, were found to yield quite satis- 
factorily ... as well, in fact, as those grown in rotation with fertilized 



SOIL FERTILITY 



161 



Table 12. — Yields of Cotton, Corn and Peanuts in Cropping Systems that 
Include Hogged and Dug Peanuts. Wiregrass Substation, Headland, Ala- 
bama, 1939-1946, Inclusive (1). 
TiFTON Fine Sandy Loam 



Crop- 
ping 
system 



Crop 



Fertilizer'' 



Average Yield 
1939-46 



1 
2 
3 

4 

5 

6 

7 
8 
9 

10 

11 

12 

13 



Peanuts — Dug . . . , 
Peanuts — Hogged . 



Peanuts — Dug . 
Cotton 



Cotton 

Peanuts — Dug . 



Cotton 

Peanuts — Hogged . 



Cotton. 
Corn . . . 
Corn. . . 



Corb 

Peanuts — Dug . 



Corn 

Peanuts — Hogged . 



Corn 

Peanuts — Hogged . 
Cotton 



Peanuts — Dug . 

Corn 

Cotton 



Peanuts — Dug. 

Corn 

Cotton 



Pounds seed cotton 
and peanuts, 
Bushels corn 







602 

1524 


0-8-8 
6-8-8 


1455 
975 


6-8-4 
0-8-4 


1207 
1627 


0-8-4 



1380 
1791 


6-8-4 


1416 





10.0 


6-8-4 


33.3 


0-8-4 
0-8-4 


23.0 
1640 


0-8-4 
0-8-4 


40.6 
1777 




6-8-4 


42.1 
1744 
1384 




6-8-4 


1507 

20.6 

799 




6-8-12 


1566 
25.6 
1176 



» 600 pounds per acre. Cotton received 6-10-4 and all other crops no fertUizer. 1932-1938. 

cotton or corn and dug. Higher yields were obtained, however, when 
the hogged peanuts were grown in rotation with a fertilized crop of corn 
or cotton. The yield of corn grown in rotation with hogged peanuts was 
some 17 bushels greater than when rotated with dug peanuts. Cotton 
yields were also much greater in rotation with hogged peanuts. The 



162 



THE PEANUT— THE UNPREDICTABLE LEGUME 



higher yields of crops following hogged peanuts were probably due in 
part to the nitrogen returned to the soil in plant residues. 

Other experiments in Alabama (2) have shown that when peanuts 
were dug the yields of the succeeding crops were decreased, but when 
harvested by hogs the yields of the following crops were increased. Thus 
the method of harvesting may determine whether peanuts are soil deplet- 
ing or whether they may actually increase the productivity of the soil. 



Table 13. — Interplanted Corn and Peanuts in a Corn-Cotton Rotation. 
Alabama Agricultural Experiment Station (1). 




Yields per acre 


Cropping'' 


Seed cotton 
Pounds 


Corn 
Bushels 


Peanuts^ 
Pounds 


Brewton Field", 1938-1946 


Cotton, corn 


551 
741 


12.9 

11.8 


394 






Prattville Fields 1932-1946 


Cotton, corn 

Cotton, corn and peanuts 


597 
840 


13.7 
10.8 


794 






Tennessee Valley Substation", 1932-1945 


Cotton, corn ... 


1,129 
1,283 


27.8 
23.4 




Cotton, corn and peanuts 


841 







» All rows 3J^ feet apart; alternate rows in corn, and peanuts. All fertilizers, 600 pounds per acre 
0-10-4, apolied to cotton. 

b Runner peanuts all years — vines returned to the land at Brewerton and Prattville, 
" Kalmia fine sandy loam. 
^ Greenville fine sandy loam. 
« Dewey silt loam. 

It should be pointed out that the differences in yields of crops following 
peanuts harvested by the two methods would undoubtedly be smaller 
were more fertilizer applied to the dug peanuts to compensate for the 
nutrients removed by the crop. Thus it appears likely that the produc- 
tivity of these soils could be maintained to a large extent through ade- 
quate fertilization. 

While the peanut is considered to be one of the most soil-depleting 
crops grown in this country, there is nothing unique in the ability of this 
crop to reduce the productivity of soils. Other crops would undoubtedly 
be equally as injurious were they harvested as peanuts normally are. In 
some sections of the world, notably in certain localities in Africa, the tops 
are left on the soils after the nuts are picked. When such a practice is fol- 



SOIL FERTILITY 163 

lowed the problem of maintaining the fertility of peanut soils is much less 
acute. In view of the fact that a large percentage of the nutrients absorbed 
by the peanut plant is found in the tops (table 1), the removal of the hay 
from peanut soils becomes a questionable practice. This is especially true 
because the organic-matter level of many soils used for growing peanuts 
is critically low and could, in part, be replenished were the peanut vines 
returned to the soil. 

The practice of interplanting peanuts with corn has been followed in 
some localities. One or both crops may be harvested for market or may 
be hogged-ofif . Experiments at three locations in Alabama were conducted 
to study the effect of interplanting corn and peanuts upon the yield of 
cotton and corn grown in a 2-year rotation. The results of these tests 
(table 13) show that the yields of cotton were higher following inter- 
planted corn and peanuts than when grown after corn alone. Further- 
more, the value of the interplanted corn plus peanuts was considerably 
greater than the corn grown alone. It should be pointed out that the 
greatest increases in cotton yields were observed at the two locations 
where the peanut vines were returned to the land. 

SUMMARY 

There appears to be universal agreement on what constitutes an 
"ideal" soil for growing peanuts. A soil well adapted to the production of 
this crop has been characterized by many as a well-drained, light-colored, 
loose, friable sandy loam, well supplied with calcium and with a moderate 
amount of organic matter. 

A study of the soil-fertility investigations with peanuts reveals a mul- 
titude of inconsistencies. Many workers have indicated that the peanut 
plant is quite unpredictable in its response to fertiHzation. While such 
would often appear to be the case, it seems that many of the apparent 
anomalies associated with the fertilization of peanuts have arisen through 
failure to evaluate fully the environmental conditions under which the 
experiments were conducted. Furthermore, due consideration must be 
given to the unique growth and fruiting habits of the peanut in interpret- 
ing experiment results. Recent fundamental studies dealing with the nu- 
trition of peanuts have been very helpful in interpreting some of the pea- 
nut fertility research data. More of such investigations are greatly needed. 
Most southern experiment stations currently recommend that peanuts 
be grown following other well-fertilized crops. When such a practice is 
followed, much of the experimental evidence suggests that little may be 
gained from additions of nitrogen, phosphorus or potassium directly to 



164 THE PEANUT— THE UNPREDICTABLE LEGUME 

the crop. There is some evidence that certain varieties of peanuts may 
respond to relatively large additions of nitrogen, despite the fact that the 
crop is a legume. However, large quantities of nitrogenous fertilizers are 
not commonly applied to peanuts. Unless the crops grown in rotation 
with peanuts receive very liberal applications of potassium, it may be 
necessary to apply some fertilizers containing this element directly to the 
peanuts in order to obtain maximum yields and to maintain the fertility 
of the soil. 

The importance of calcium in the nutrition of peanuts has long been 
recognized. Generally the response of peanuts to amendments of calcium 
has been more consistent than to additions of any other nutrient. Appar- 
ently one of the primary functions of calcium in peanut nutrition is to 
improve the quality of the nuts, or more specifically, to aid in the devel- 
opment of the kernel. The better quality of nuts grown in soils well sup- 
plied with calcium is evidenced by a lighter, firmer hull and few unfilled 
pods (pops). 

One of the most common methods of supplying the calcium needs of 
peanuts is to apply gypsum to the foliage at early blooming. However, 
when the soil has been limed adequately little benefit may be derived from 
additions of gypsum. For a number of reasons, it would appear better to 
maintain an adequate calcium level in peanut soils through the use of a 
liming material rather than by additions of a neutral salt such as gypsum. 
Calcitic lime should be superior to one high in magnesium. 

Some investigators have obtained a fair correlation between the ex- 
changeable calcium levels in soils and the response of peanuts to amend- 
ments of lime or gypsum, and expected responses have been predicted on 
such a basis. However, for a more exact estimate of the need for calcium 
in peanut soils, the nature of the soil colloids and the percentage base 
saturation, as well as the exchangeable calcium level, need to be con- 
sidered. 

There is little evidence that any of the so-called "secondary" and 
"minor" elements are normally limiting the yield of peanuts, except per- 
haps on heavily limed soils where deficiencies of manganese may occur. 

A review of peanut-fertilization research suggests that too little atten- 
tion has been given to the method of placement of peanut fertilizers. 
Studies have shown that in order for calcium to be most effective it 
should be localized in the zone in which the pods develop. On the other 
hand, a high concentration of potassium in the fruiting zone may be 
harmful because of its effect on fruit quality, especially at low-calcium 
levels. Furthermore, fertilizer materials, if placed too close to the seed at 



SOIL FERTILITY 165 

planting, may impair germination. Perhaps fertilizer materials would be 
found to be more beneficial if a greater effort were made to use them 
properly. 

There is much evidence that peanut varieties exhibit marked differ- 
ences in their response to certain nutrients. Furthermore, strains within 
a given variety have been found to differ greatly in response to fertiliza- 
tion. These differences may account in part for some of the existing con- 
fusion regarding the fertilization of peanuts. Certainly the plant breeder 
must give ample consideration to such differences in evaluating peanut 
varieties. 

Peanuts remove relatively large amounts of certain nutrients from the 
soil with the normal systems of management in which both hay and nuts 
are harvested. Yet, because of the fact that peanuts have not been found 
to be as responsive to direct applications of fertilizer materials as other 
crops there is a tendency to supply less of some nutrients than is removed 
from the soil by the crop. It is by no means a desirable practice to grow 
peanuts continuously on the same soil. Many experiment stations recom- 
mend that they not be grown more than once every 3 or 4 years. Peanuts 
may be grown satisfactorily in rotation with a number of different crops. 
Generally, it would be desirable to grow well-fertilized crops such 
as cotton, tobacco or truck crops immediately prior to peanuts in the 
rotation. 

Little organic matter is returned to the soil from a crop of peanuts. 
Furthermore, after peanuts are harvested conditions are quite favorable 
for the rapid oxidation of the organic matter present in the soil. Legumin- 
ous green manure crops are well suited to peanut rotations and their use 
may help to maintain an adequate level of organic matter and insure a 
good physical condition. It is especially important that peanut soils be 
kept loose and friable because the pegs must penetrate the surface in 
order for nuts to be formed. 

With the normal methods of harvesting, peanuts are considered to 
be one of the most soil-depleting crops grown in this country. However, 
when the crop is harvested by grazing hogs or when the nuts are picked 
off and the vines returned to the soil peanuts may actually increase the 
productivity of the soil. Therefore, there appears to be nothing unique 
about the soil-depleting powers of the peanut as some have indicated. 

It has been suggested (42) that large increases in peanut yields 
cannot be expected from fertilizer treatments as only the nuts produced 
in a relatively short period of continuous blooming of the plant can be 
saved at harvest. However, even though direct responses to fertilization 



166 THE PEANUT— THE UNPREDICTABLE LEGUME 

may not be pronounced, it is reasonable to expect increased yields of 
peanuts through the introduction of better varieties, by the more 
effective control of diseases and insect pests and through the adoption of 
better cultural practices such as the use of closer spacing. As such 
yield increases are realized and as more nutrients are j-emoved from the 
soil by the harvested crop, the problem of maintaining the fertility of 
the peanut soils will undoubtedly become increasingly acute. It is likely 
that more fertilizers may eventually have to be applied to peanuts or 
to the other crops grown in the rotation if the productivity of peanut 
soils is to be maintained. 



SELECTED REFERENCES 

(1) Anon. 

1947. UNPUBLISHED DATA. Ala. Agr. Expt. Sta. 

(2) 

(3) 



1939. THE EFFECT OF "DIGGING" AND "hOGGING" PEANUTS ON COTTON YIELDS. 

Ala. Agr. Expt. Sta. Leaflet No. 18. 



(4) 
(5) 
(6) 
(7) 

(8) 
(9) 

(10) 

(11) 

(12) 

(13) 
(14) 



1937. FERTILIZER AND CROP EXPERIMENTS ON CERTAIN SOILS OF THE BLACK 

BELT. Ala. Agr. Expt. Sta. Cir. 78. 



1934. PEANUTS. Ala. Agr. Expt. Sta. Leaflet No. 5. 



1947. UNPUBLISHED DATA. No. Fla. Expt. Sta. 



1947. UNPUBLISHED DATA. Ga. Agr. Expt. Sta. 



1947. FERTILIZER AND AMENDMENTS FOR PEANUTS. Ga. Agr. Expt. Sta. Ann. 

Rpt. 59:23-25. 



1946. Ga. Agr. Expt. Sta. Ann. Rpt. 58:28. 



1944. DIFFERENCES IN ScUrotium rolfsii ON Spanish peanuts caused by 
FERTILIZER TREATMENTS. Ga. Agr. Expt. Sta. Ann. Rpt. 56:17. 



1944. FERTILIZERS AND AMENDMENTS FOR PEANUTS. Ga. Agr. Expt. Sta. Ann. 

Rpt. 56:17-20. 



1946. PEANUT FERTILITY TESTS. Ga. Coastal Plain Expt. Sta. Ann. Rpt. 26: 
16-17. 



1944. PEANUT FERTILIZER STUDIES. Ga. Coastal Plain Expt. Sta. Ann. Rpt. 
24:25-27. 



1942. PEANUT FERTILIZERS. Ga. Coastal Plain Expt. Sta. Ann. Rpt. 22:31-35. 
UNPUBLISHED DATA. Miss. Agr. Expt. Sta. 



1946. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 69:37-47. 



SOIL FERTILITY 167 

(IS) Anon. 

1947. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 70:21-26. 
(16) 

(17) 

(18) 

(19) 

(20) 

(21) 



1945. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 68:30-35. 



1944. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 67:37-43. 



1943. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 66:41-51. 



1942. RESEARCH AND FARMING. N. C. Agr. Expt. Sta. Ann. Rpt. 65:33-38. 



1948. EL cuLTivo DEL MANi o CACAUETE. Ministerio de Agricultura Y Gan- 
deria Division of Agricultura. Bogota, Columbia. 



1949. cuLTUURAANWijziNGEN vooR AARDNOTEN. Algemeen Proefstation voor 
de Landbouw Cultuurtechnisch InStituut. (Indonesia). 



1934. THE PEANUT. Jamaica Agr. Soc. Jour. 38 (10):639-640. 



1929. CULTIVATION OF GROUNDNUTS. Jamaica Agr. Soc. Jour. 33:307-309. 



1946. A SURVEY OF THE RESEARCH STATUS OF THE PEANUT INDUSTRY. SoUthem 

Research Institute. 
(22) 

(23) 

(24) 
(25) 
(26) 

1920. IMPROVED METHODS OF CULTIVATING THE GROUNDNUT IN SENEGAL. 

Inter. Rev. of the Science and Practice of Agriculture 1 1 :982-986. 

(27) Albrecht, H. R. 

1944. factors influencing the effects of innoculation of peanuts 
GROWN ON NEW PEANUT LANDS. Proc. Soil Sci. Soc. Amer. 8:217-220. 

(28) Arnon, D. I., Fratzke, W. E. and Johnson, C. M. 

1942. HYDROGEN-ION CONCENTRATION IN RELATION TO ABSORPTION OF IN- 

ORGANIC NUTRIENTS BY HIGHER PLANTS. Plant Phys. 17:515-524. 

(29) Batten, E. T. 

1943. PEANUT PRODUCTION. Va. Agr. Expt. Sta. Bui. 348. 
(30) 

1942. EXPERIMENTS WITH COTTON AND PEANUTS AND CROPS GROWN IN ROTA- 

TION WITH THEM IN NANSEMOND COUNTY. Va. Agr. Expt. Sta. Bul. 229. 
(31) AND CUMINGS, G. A. 

1946. PEANUT FERTILIZER PLACEMENT. Va. Agr. Expt. Sta. Ann. Rpt., page 26. 

(32) AND HUTCHESON, T. B. 

1932. EXPERIMENTS WITH LIME, FERTILIZERS AND VARIETIES OF FIELD CROPS 
IN THE COTTON AND PEANUT SECTION OF VIRGINIA. Va. Agr. Expt. 

Sta. Bul. 284. i^ 

(33) Beattie, W. R. and Beattie, J. H. 

1943. PEANUT GROWING. USDA Farmers Bul. 1656. ^ 

(34) Bledsoe, R. W., Comar, C. L. and Harris, H. C. '^~ 

1949. absorption of radioactive calcium by the peanut fruit. Science 
109:329-330. 



168 THE PEANUT— THE UNPREDICTABLE LEGUME 

(35) Bledsoe, Harris, H. C. and Clark, F. 

1945. the importance of peanuts left in the soil in the interpretation 

OF INCREASES IN YIELD DUE TO SULFUR TREATMENTS. Jour. Amer. 

Soc. Agron. 37:689-695. 

(36) Brady, N. C. 

1947. the effect of period of calcium supply and mobility of calcium 

IN THE PLANT ON PEANUT FRUIT FILLING. PrOC. Soil Sci. SoC. Amer. 

12:336-341. 

(37) AND COLWELL, W. E. 

1945. YIELD AND QUALITY OF LARGE-SEEDED TYPE PEANUTS AS AFFECTED BY 
POTASSIUM AND CERTAIN COMBINATIONS OF POTASSIUM, MAGNESIUM 

AND CALCIUM. Jour. Amer. Soc. Agron. 37:429-442. 

(38) , Reed, J. F. and Col well, W. E. 

1948. THE EFFECT OF CERTAIN MINERAL ELEMENTS ON PEANUT FRUIT FILLING. 

Jour. Amer. Soc. Agron. 40:155-167. 

(39) Bryan, O. C. 

1923. effect of reaction on growth, nodule formation and calcium 

CONTENT OF ALFALFA, ALSIKE CLOVER AND RED CLOVER. Soil Sci. 

15:23-35. 

(40) BURKHART, L. AND COLLINS, E. R. 

1942. MINERAL NUTRIENTS IN PEANUT PLANT GROWTH. PrOC. Soil Sci. SoC. 

Amer. 6:272-280. 

(41) Chaffin, W. 

1945. peanuts in Oklahoma. Okla. Agr. Ext. Ser, Cir. No. 410. 

(42) Collins, E. R. 

1943. maintaining fertility when growing peanuts. Better Crops 27 

(2):6-10. 

(43) and Morris, H. D. 

1941. soil fertility studies with peanuts. N. C. Agr. Expt. Sta. Bui. 
330. 

(44) Colwell, W. E. and Brady, N. C. 

1945. the EFFECT OF CAI.CIUM ON CERTAIN CHARACTERISTICS OF PEANUT 

FRUIT. Jour. Amer. Soc. Agron. 37:696-708. 

(45) AND 

1945. THE EFFECT OF CALCIUM ON YIELD AND QUALITY OF LARGE-SEEDED 

TYPE PEANUTS. Jour. Amer. Soc. Agron. 37:413-428. 

(46) AND 

1943. SOIL FERTILITY STUDIES WITH PEANUTS. N. C. Agr. Expt. Sta. Bul. 

(47) , AND Reed, J. F. 

1946. FERTILIZING PEANUTS IN NORTH CAROLINA.' N. C. Agr. Expt. Sta. Bul. 

356 

(48) Downing, J. C, Aull, G. H., Goodman, K. V. and Peterson, M. J. 

1944. PEANUT PRODUCTION POSSIBILITIES IN SOUTH CAROLINA. S. C. Agr. 

Expt. Sta. Bul. 351. 

(49) DuGGAR, J. F., Cauthen, E. F., Williamson, J. T. and Sellars, O. H. 

1917. peanut: tests of varieties and fertilizers. Ala. Agr. Expt. Sta. 
Bul. 193:1-32. 

(50) and Funchess, M. J. 

1911. lime for ALABAMA SOILS. Ala. Agr. Expt. Sta. Bul. 161:301-324. 



SOIL FERTILITY 169 

(51) EjERCITO, J. M. 

1934. PEANUTS IN THE PHILIPPINES. Philippine Jour, of Agr. 5 (2):47-67. 

(52) Ferris, E. B. 

1922. peanuts. Miss. Agr. Expt. Sta. Bui. 208. 

(53) Freid, M. and Peech, M. 

1946. the comparative effects of lime and gypsum upon plants grown 
ON acid soils. Jour. Amer. Soc. Agron. 38:614-623. 

(54) Gore, U. R. 

1941. culture and fertilizer studies with peanuts. Ga. Agr. Expt. 

Sta. Bui. 209. 

(55) 

1941. peanut fertilizer studies in GEORGIA. Proc. Assoc, of Southern Agr. 

Workers 42:103-104. 

(56) Harper, J. N. 

1920. money in peanut growing. American Fertilizer 52 (3) :67-89. 

(57) Harris, H. C. 

1949. copper deficiency of peanuts, Proc. of Southern Agr. Workers 
46:164. 

(58) , Tisdale, W. B. and Tissot, A. N. 

1946. importance of experimental technique in fertilizer, dusting and 

calcium experiments with FLORIDA RUNNER PEANUTS. PrOC. Soil 

Sci. Soc. Amer. 11:413-416. 

(59) Hendrix, W. E., Butler, C. P. and Goodman, K. V. 

1943. peanut production possibilities in GEORGIA. Ga. Agr. Expt. Sta. 

Bui. 228. 

(60) Hill, A. G. 

1947. OIL plants in east Africa (1) groundnuts. East Africa Agr. Jour. 

12:140-146. 

(61) Jones, B. W. 

1911. THE PEANUT PLANT. N. Y. Orange Judd Co. 1885. R'ev. 

(62) Keele, W. D. 

1935. PEANUT GROWING. Agr. Gaz. of New South Wales 46:503-508. 

(63) 

1918. THE PEANUT. Agr. Gaz. of New South Wales 29:137-142, 262-273, 
338-343, 429-433, 471-479. 

(64) Kerr, J. A. 

1946. PEANUT GROWING. Queensland Agr. Jour. 

(65) KiLLiNGER, G. B., Stokes, W. E., Clark, F. and Warner, J. D. 

1947. peanuts in Florida. Fla. Agr. Expt. Sta. Bui. 432. 

(66) Krauss, F. G. 

1917. peanuts, how to grow and use them. Hawaii Agr. Ext. Bui. 5. 

(67) Langley, B. C, Reynolds, E. G. and Dunlap, A. A. 

1945. summary of peanut investigations in texas. Texas Agr, Expt. Sta, 
Prog. Rpt. 943. 

(68) McClelland, C. K. 

1944. peanut production experiments, 1931-1941. Ark. Agr. Expt. Sta. 

Bui. 448. 

(69) Mann, H. B. 

1935. the relation of soil treatments to the nodulation of peanuts. 
Soil Sci. 40:423-437. 



170 THE PEANUT— THE UNPREDICTABLE LEGUME 

(70) Marin, L. 

1935. EL CACAHUATE BULLETIN. Secretaria de Agricultura Y Forraento 
(Mexico). 

(71) MaSSIBOT, J. A. AND ViDAL, R. 

1947. EXPERIMENTATION PRELIMINAIRE DE LA FUMUEE DES TERRES A ARA- 

CHiDE DE LA REGION DE LOUGA (SENEGAL). L'Agronomie Tropicale 
2:247-278. 

(72) Mehlicii, a. and Colwell, W. E. 

1946. absorption of calcium by peanuts from kaolin and bentonite 

AT VARYING LEVELS OF CALCIUM. Soil Sci. 61 :369-374. 

(73) AND Reed, J. F. 

1947. THE INFLUENCE OF THE TYPE OF COLLOID AND DEGREE OF CALCIUM 

SATURATION ON FRUIT CHARACTERISTICS OF PEANUTS. PrOC. Soil Sci. 

See. Amer. 11:201-205. 

(74) MiDDLETON, G. K., COLWELL, W. E., BrADY, N. C. AND SCHULTZ, Jr., E. F. 

1945; THE BEHAVIOR OF FOUR VARIETIES OF PEANUTS AS AFFECTED BY CALCIUM 

AND POTASSIUM VARIABLES. Jour. Amer. Soc. Agron. 37:443-457. 

(75) AND Farrior, J. W. 

1941. RESPONSE of peanut VARIETIES TO DIFFERENT FERTILITY LEVELS. PrOC. 

Assoc, of Southern Agr. Workers 42:101-102. 
(76) Morris, H. D. 

1941. YIELDS OF peanuts AS INFLUENCED BY FERTILIZER. M. S. Thesis, 

Agron. Dept., N. C. State College, Raleigh. 
(77) AND Pierre, W. H. 

1947. THE EFFECT OF CALCIUM, PHOSPHORUS AND IRON ON THE TOLERANCE OF 

LESPEDEZA TO MANGANESE TOXICITY IN CULTURE SOLUTIONS. PrOC. 

Soil Sci. Soc. Amer. 12:382-386. 

(78) MosER, F. 

1942. CALCIUM NUTRITION AT RESPECTIVE PH LEVELS. PrOC. Soil Sci. SoC. 

Amer. 7:339-344. 

(79) Moses, D. and Sellschop, J. P. F. 

1946. THE PEANUT IN SOUTH AFRICA. Jour. Dept. Agr. Union S. Africa 12: 
369-385. 

(80) Murray, G. H. 

1935. PEANUTS AS A CROP FOR NEW GUINEA. New Guinea Agr. Gaz. 3:15. 

(81) Nelson, W. L. 

1948. UNPUBLISHED DATA. N. C. Agr. Expt. Sta. 

(82) O'Brien, R. E. 

1944. FIELD EXPERIMENTS WITH PHOSPHATIC FERTILIZERS. Va. Agr. Expt. 

Sta. Bui. 364. 

(83) Paden, W. R. 

1940-1943. PEANUTS IN SOUTH CAROLINA. S. C. Agr. Expt. Sta. Mimeogr. 
Sheets. 

(84) Parham, S. a. 

1942. peanut production in the coastal plain of georgia. 
Ga. Coastal Plain Expt. Sta. Bui. 34. 

(85) Pate, W. F. 

1931. FERTILIZING PEANUTS. American Fertilizer, page 36. 



SOIL FERTILITY 171 

(86) Peech, M. and Bradfield, R. 

1943. the effect of lime and magnesia on the soil potassium and on 

THE ABSORPTION OF POTASH BY PLANTS. Soil Sci. 55:37-48. 

(87) Pierre, W. H. and Bower, C. A. 

1943. potassium absorption in plants as affected by cationic relation- 

ships. Soil Sci. 55:23-36. 

(88) PiLAND, J. R., Ireland, C. F. and Reisenauer, H. M. 

1944. the importance of borax in legume seed production in the south. 

Soil Sci. 57:75-84. 

(89) Pollock, N. A. R. 

1934. cultivation of the peanut. Queensland Agr. Jour. 41:148-164. 

(90) 

1925. cultivation of the peanut. Queensland Agr. Jour. 24:108-113. 

(91) Prevot, p. 

1949. nutrition minerai.e de l'arachide. Oleagineux 4:69-78. 

(92) QuiNN, H. G. 

1921. the peanut. South Africa Jour, of the Dept. of Agr. 3:160-164. 

(93) Reed, J. F. and Brady, N. C. 

1948. TIME AND method OF SUPPLYING CALCIUM AS FACTORS AFFECTING 

PRODUCTION OF PEANUTS. Jour. Amer. Soc. Agron. 40:980-996. 

(94) AND CUMMINGS, R. W. 

1948. USE OF SOLUBLE SOURCES OF CALCIUM IN PLANT GROWTH. Soil Sci. 

65:103-109. 

(95) Rogers, H. T. 

1948. liming for peanuts in relation to exchangeable soil calcium 
and effect on yield, quality and uptake of calcium and 
POTASSIUM. Jour. Amer. Soc. Agron. 40:15-31. 

(96) 

1943-44. VALUE OF LIME FOR PEANUTS. Ala. Agr. Expt. Sta. Ann. Rpt. 
54 and 55:5». 

(97) SCHMEHL, W. R. 

1948. THE NATURE OF CROP RESPONSES TO LIMING AND THE INFLUENCE OF 
RATE AND METHOD OF APPLICATION ON THE YIELD AND CHEMICAL 

COMPOSITION OF PLANTS. Ph.D. Thesis. Cornell University, Ithaca, 
N. Y. 

(98) Sellschop, J. 

1942. GROUNDNUT PRODUCTION. Farming in S. Africa 17:651-654, 670. 

(99) Shear, G. M. and Batten, E. T. 

1948. manganese deficiency of peanuts in VIRGINIA. Proc. Assoc. Southern 
Agri. Workers 45:143-148. 

(100) Skinner, J. J., Nelson, W. L. and Collins, E. R. 

1946. potash and lime requirements of cotton grown in rotation 
WITH peanuts. Jour. Amer. Soc. Agron. 38:142-151. 

(101) SoMMER, A. L. and Baxter, A. 

1942. DIFFERENCES IN GROWTH LIMITATION OF CERTAIN PLANTS BY MAG- 
NESIUM AND MINOR ELEMENT DEFICIENCIES. Plant Phys. 17:109-115. 

(102) , Wear, J. I. and Baxter, A. 

1940. THE RESPONSE TO MAGNESIUM OF SIX DIFFERENT CROPS ON SIXTEEN 

ALABAMA SOILS. Proc. Soil Sci. Soc. Amer. 5:205-212. 



172 THE PEANUT— THE UNPREDICTABLE LEGUME 

(103) St ANSEL, R. H. 

1935. PEANUT GROWING IN THE GUI.F COAST PRAIRIE OF TEXAS. Texas 

Agr. Expt. Sta. Bui. 503:5-16. 

(104) Stokes, W. E. and Camp, J. P. 

1931. EFFECT OF LANDPLASTER OR GYPSUM ON HAY AND SEED PRODUCTION 

OF PEANUT VARIETIES. Fla. Agr. Expt. Sta. Ann. Rpt., page 45. 

(105) , Leukel, W. a. and Camp, J. P. 

1931. EFFECTS OF POTASH ON YIELD AND QUALITY OF SPANISH PEANUTS. 

Fla. Agr. Expt. Sta. Ann. Rpt., page 44. 

(106) Stuckey, H. P 

1945. WORK WITH PEANUTS AT THE GEORGIA EXPERIMENT STATION. Peanut 

Jour, and Nut World 24:25-26. 

(107) Sturkie, D. G., Schultz, Jr., E. F. and Albrecht, H. R. 

1943-44. Effect of high rates of nitrogen in fertilizer on the yield 
OF peanuts. Ala. Agr. Expt. Sta. Ann. Rpt. 54 and 55:12. 

(108) TiMSON, S. D. 

1930. THE GROUNDNUT. Rhodesia Dept. of Agr. Bui. No. 768. 

(109) Valdivia, M. a. 

1936. el mani. Revista de Agricultura (Cuba) 18 (4):5-22. 

(110) Waldron, R. a. 

1919. THE peanut; ITS HISTORY, HISTOLOGY, PHYSIOLOGY AND UTILITY. Cont. 

Bot. Lab., Univ. of Pa. IV:302-338. 

(111) Wenholz,'H., Nicholson, G. and Wolk, P. C. 

1926. peanuts. New South Wales Agr. Gaz. 37:457-462, 512-516, 613-619, 
762-76», 842-846. 

(112) West, H. O. 

1942. peanut production. Miss. Agr. Expt. Sta. Bui. 366. 

(113) York, Jr., E. T. 

1949. calcium-potassium interrelations in soils and their influence 
upon the yield and cation content of certain crops. Ph.D. 
Thesis. Cornell University. 



CHAPTER VI 



CULTURAL PRACTICES 

By 
D. G. STURKIE AND J. T. WILLIAMSON^ 

Research work involving some of the cultural practices with peanuts 
has been rather limited. Most of the experiment stations have conducted 
spacing tests; several have carried time-of-planting and seed-treatment 
tests ; a few have studied seed preparation, seed types, and disease and 
insect control by dusting. However, the data on soil preparation, plant- 
ing depths, cultivation, harvesting, curing, picking and perhaps other 
phases of this subject are either extremely meager or nonexistent. Station 
publications on many of these subjects carry only the authors' opinions. 
The authors of this chapter are in accord with most of these views, and, 
where data are not available, they have included such opinions as the 
best information obtainable on the subject. 

PLANTING 

Preparation of the Soil 

There are very few data from controlled experiments with different 
methods of preparing land for peanuts. However, there is practically 
unanimous agreement among all research workers and extension agrono- 
mists that the land should be thoroughly and completely prepared before 
planting. Land is prepared for peanuts in much the same way as for 
cotton. Plowing is done early when there is no winter cover crop on the 
land. It is difficult to prepare land properly for peanuts if a large 
growth of residue from the preceding crop is turned under just prior 
to planting. For this reason plowing in the late fall or early winter is 
practiced frequently in order to permit complete decorhposition of 
residues before time for planting. When a winter cover crop such as 

^ D. G. Sturkie and J. T. Williamson are agronomists, Alabama Agricultural Experiment 
Station. 

173 



174 THE PEANUT— THE UNPREDICTABLE LEGUME 

lupine or vetch is used, it is plowed under at least 30 days before«peanuts 
are planted. In case weeds come up on the field, the land is disked to 
eradicate the weeds. The land is harrowed and dragged immediately 
before planting. 

There are no data on depth of preparing the soil. Apparently, ex- 
cessively deep preparation is to be avoided. Most lands should be pre- 
pared to a depth of from 5 to 7 inches. 

Fertiliser Applications 

Although the subject of peanut fertilization has already been dis- 
cussed in Chapter V, brief comments are included here. 

Many research workers have found that peanuts following a crop that 
was well -fertilized with mineral fertilizers do not give increased yields 
from direct applications. However, it is still a general practice to apply 
fertilizers in the drill at planting and in some cases as top-dressing 
materials -later in the season. 

Fertilizers that are used in the drill are applied either to the side and 
slightly below the seed or well mixed with the soil so that they will not 
come in contact with the seed and thus reduce the stand. Many research 
workers recommend that fertilizers be applied 1 to 2 weeks ahead of 
planting,. 

In some sections it has recently become a common practice to apply 
fertilizers on the row just as the plants are emerging. This is especially 
true of potash materials. When this practice is followed the fertilizer is 
applied when the plants are dry in order to avoid burning. Cultivation 
with a weeder or rotary hoe should follow immediately so as to remove 
any fertilizer that may have come in contact with the plants. Batten (2) 
recommends that only concentrated potash salts be used in the fertilizer 
application made before planting because the use of a greater volume of 
the low-grade salts required to obtain the amount of potash needed often 
causes poor germination. 

Use of gypsum on the foliage of large-type peanuts at blooming 
time has given outstanding increases in yields in North Carolina and Vir- 
ginia. Experiments in other States have indicated little or no benefit 
from this practice when Spanish or the small runner-type peanut is 
grown. Studies have shown that gypsum is most beneficial if applied 
when the peanuts begin blooming. Gypsum has usually been dusted on 
the foliage by hand, but the use of machines for application is increasing. 

Where limestone is applied in the drill before planting, it should be 
used as a separate treatment from the fertilizers that are applied at this 



CULTURAL PRACTICES 



175 



time. It is believed, however, that the best practice is to plant peanuts on 
land that has been adequately limed by previous broadcast applications. 

Time of Planting 

Throughout the greater part of the commercial peanut area, planting 
of the main crop is done between April 10 and May 10. Peanuts are 
planted from early March in parts of Texas and Florida to as late as 
June 15 in Virginia and North Carolina. The young peanut plant is 
capable of withstanding considerable cold. Therefore, peanuts may be 
planted earlier than cotton. The recommendations made by most agrono- 
mists are for planting at a reasonably early date. The best planting date is 



Table 1- 


-Annual and Average Yields of Spanish Peanuts Planted at Dif- 
ferent Dates, Lauderdale, Mississippi, 1940-1941' 




Date of planting 


Yield per acre 




1940 


1941 


Average 






Pounds 


Pounds 


Pounds 


April IS 


1,550 
1,200 
1,356 


920 
860 
610 


1,335 


May IS 


1,030 


June IS 


983 







» All plots received 400 pounds per acre of 0-8-4 with basic slag as a source of phosphorus; peanuta 
planted in 30-inch rows, 6 to 8 inches apart in the drill. 

probably about 2 weeks after the average date of the last killing frost. 
Results of time-of-planting experiments show that farmers could very 
probably increase their yields by planting earlier than customary. In the 
Gulf Coast region, a fair yield may be expected from Spanish peanuts 
planted as late as July 1. Runner-peanut yields decline very rapidly as the 
date of planting is delayed. 

Results from experiments on dates of planting in Mississippi (18) are 
given in table 1. These results show that yields from peanuts planted 
early are definitely higher than from peanuts planted at later dates. 

Peanuts planted in April, May and June 1940-1943 at Rocky Mount, 
North CaroHna (6) produced average yields of 1,215 pounds, 1,151 
pounds and 710 pounds of nuts per acre, respectively. An exception to 
the above trend was noted in 1944 when slightly higher yields were 
obtained from the May than from the April planting. 

Results of 10-year experiments at Tifton, Georgia (8), as shown in 
table 2, also indicate an advantage of early planting of both Spanish and 
runner peanuts. 



176 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 2 — 
Dates, 


-Average Yields of Unfertilized Peanuts Planted 
Georgia Coastal Plains Experiment Station, Tifton 


AT Different 
1934-1943.' 




Planting date 






Yield of unshelled nuts per acre 




Spanish 


North Carolina 
Runner 












Pounds 


Pounds 


March 15 


1,388" 
1,338 
1,335 
1,244 
1,062 
645 




1,925" 


April 1 . . 










1,860 


April 15 


1,804° 


May 1 


1,590 


May 15 


1,313 


June 1 


866 







• No fertilizer used. Tests followed a general rotation of field crops. 

*> 8-year average, no data for 1934 and 1935. 

*> 9-year average, no data on March 15 planting in 1934 or on April IS planting in 1943. 

Yields from experiments conducted with Spanish peanuts at various 
Alabama locations are given in table 3. Except at Fairhope, where early 
plantings were damaged by rodents, these results also show a very defi- 
nite advantage for early seeding. Planting at or about the last killing- 
frost date resulted in a good yield of peanuts. Slightly higher yields were 
obtained by delaying the planting 2 weeks after the last killing frost. 
Delaying the planting an additional 2 weeks, however, resulted in marked 
reduction in the yield. 

In a date-of-planting experiment with runner peanuts at Auburn, 



Table 3. — Average Yields of Spanish Peanuts Planted at Different Dates 
AT Various Locations in Alabama, 1943-1946 



Location 


Years 


Average yields per acre' 


1st planting^ 


2nd planting 


3rd planting 




Number 


Pounds 


Pounds 


Pounds 




2 
3 
4 
2 
4 
1 


1,657 
1,096 
1,016 
1,706 
1,699 
1,940 
1,426 


2,264 
981 
1,154 
1,345 
1,729 
1,941 
1,477 


2,109 


Prattville 


840 


Auburn 


983 




1,091 


Crossville 


1,562 


Belle Mina 


1,781 




1,305 







■ Yields are average of four plots; planting rate per acre 90 pounds of hand -shelled, and 60, 90 and 
135 pounds of unshelled seed, respectively. 

b Plantings made at approximately 15-day intervals, first planting at about the average date of last 
killing frost at each location and varied from March 9 at Fairhope to April 17 at Crossville. 



CULTURAL PRACTICES 



177 



Table 4. — Two- Year Average Yields of Runner Peanuts Planted on Norfolk 
Sandy Loam at Different Dates, Auburn, Alabama, 1945-1946" 



Date of planting 


Yield per acre 




Pounds 


March 15 
April 5 
April 25 


1,064 

1,268 

994 



« 300 pounds per acre of 0-14-10 applied before planting; rows 30 inches apart; 90 pounds of unslielled 
seed planted per acre. 

Alabama, the highest yield was obtained from the April 5 planting. The 
results are reported in table 4. 

Runner peanuts were planted at 10-day intervals from April 5 to June 
15, 1939-1946, inclusive, in a test at Prattville, Alabama. The average 
yields for all years are shown in table 5. Highest yields were obtained 
from planting on April 5. For some unexplainable reason, peanuts planted 
on April 15 produced less yield than those planted on either April 5 or 
25 in 6 of the 8 years that the experiment was conducted. 

Method oj Planting 

Peanuts are usually planted in a shallow furrow and are covered 
to a depth of 1J4 to 3 inches on light soils and 1 to 2 inches on heavier 
soils. Under dry conditions, still deeper covering is recommended. After 
the seed are covered, the top of the seedbed is slightly below ground 
level. This allows early cultivation with a weeder or rotary hoe without 
danger of injury to young plants. 

Table 5. — Average Yield of Runner Peanuts Planted at Different Dates, 
Prattville Experiment Field, Prattville, Alabama, 1939-1946" 



Date of platting 



Yield marketable 
peanuts per acre 



Pounds 



April 5. 
April IS 
April 25 
May 6. 
May 17, 
May 25 , 
June 5. 
June 15. 



1,570 
1,417 
1,498 
1,346 
1,260 
1,166 
1,051" 
742'' 



» Rows 36 inches apart; hills spaced uniformly each year but varied from 8 to 12 inches from year to 
year. No fertilizers applied to peanuts. 
b 7-year average; not included in 1939. 



178 



THE PEANUT— THE UNPREDICTABLE LEGUME 



In some localities the land is bedded before planting. At the time of 
planting, the bed is opened with a small shovel or bull-tongue scooter 
large enough to clean the beds and deep enough to level the top. 

After planting, the row should be slightly below or about even with 
the middle and with a slight ridge in between. If the land is freshly 
broken, usually no bed is formed. In this case, planting is made in a 
small open furrow and the seed are covered sufficiently to level the surface 
of the furrow slightly below the middle surface. Planting preparation in 
any case should leave the ground in proper shape for the use of weeders 
or rotary hoes, or for barring-off rows. 

Spacing of Peanuts 

Spacing tests to determine distances between rows and spacing of 
hills in the row have been conducted by most of the experiment stations 

Table 6. — ^Average Yields of Runner Peanuts Spaced at Different Distances 
IN the Row, Wiregrass Substation, Headland, Alabama, 1936-1943» 



Spacing 


Average yields per acre 


Between rows 


Between hills 


Inches 


Inches 


Pounds 


42 

42 
42 
42 


7 
14 
21 
28 


1,666 
1,594 
1,377 
1,326 



• 400 pounds per acre 0-8-4 used before plantinsn 200 pounds per acre of gypsum applied as a top 
dressing when blooming began, 

in the peanut-growing States. These tests have been made with both 
bunch- and runner-type peanuts. In general, the results show that narrow 
rows and thick spacing in the row produces the largest yields. When 
plants are spaced wide in the drill some of the larger types of peanuts 
produce nuts that are known as Jumbos. 

Alabama Agricultural Experiment Station Results. Reported in table 
6 are average yields from a spacing test of runner peanuts conducted for 
8 years, 1936-1943, at the Wiregrass Substation, Headland. Highest 
yields were obtained from plants spaced 7 inches apart in the row. 

From an experiment conducted at Auburn, Alabama, 1918-1922, in- 
clusive, Funchess and Tisdale (5) found that Spanish peanuts must be 
planted thick for large yields. They obtained extreme yields of 1,785 
pounds of nuts per acre from 4-inch spacing in 18-inch rows and 813 



CULTURAL PRACTICES 



179 



pounds from 12-inch hills in 36-inch rows. Average results for the 5-year 
period of the test are given in table 7. 

Arkansas Agricultural Experiment Station Results. McClelland ( 10) 
reported that tests with rows as narrow as 12 to 18 inches apart were 
conducted in 1919. However, these tests were not continued because of 
the difficulties encountered in cultivating these narrow rows. The yields 
of peanuts and of hay were larger than when the peanuts were planted 
in wider rows. 

Table 7. — Average Yields of Spanish Peanuts when Planted at Different 
Spacings, Main Station, Au6urn, Alabama, 1918-1922 



Row width 


Spacing in rows 


Average yield nuts per acre 


Inches 


Inches 


Pounds 


18 


4 


1,785 


24 


4 


1,581 


30 


4 


1,308 


36 


4 


1,299 


18 


8 


1,323- 


24 


8 


1,170 


30 


8 


1,146 


36 


8 


813 


18 


12 


1,437 


24 


12 


1,158 


30 


12 


1,002 


36 


12 


813 



Spacing experiments conducted during the period 1925-1930, in- 
clusive, also were reported. The average results are given in table 8. 
Spanish and Valencia varieties were used in these tests. Higher yields 
of both nuts and hay were obtained from the Spanish variety when 
grown in 30-inch rows and spaced 6, 8 or 9 inches apart in the drill. The 
Valencia variety produced highest yield in either 30- or 36-inch rows with 
6, 8 or 9 inches between the hills. 

In a later test (11), 1931-1941, highest yields of the Valencia variety 
were obtained when spaced 8 inches apart in 30-inch rows. The Spanish 
strains produced best from a 36-by-8 inch spacing. There was little diflfer- 
ence in the yield of either variety between rows of 30 and 36 inches. 
Spacings of less than 8 inches in the row were not included in the tests. 
Highest yields of hay from both varieties were obtained from 30-by-8 
inch spacing. Average yields of nuts and hay from various spacings for 
1931-1934 and for a 9-year average between 1931 and 1941 are given in 

table 9. 

Florida Agricultural Experiment Station Results. In 1928 and 1929 



180 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 8. — Average Yield of Peanuts at Different Spacings, Arkansas 
Agricultural Experiment Station, Fayetteville, 1925-1930* 



Width of rows 


Spacing in row 


Yields per acre 


Peanuts 


Hay 


Inches 


Inches 


Pounds 


Pounds 


Spanish 

30 


6-8-9 
16-12 
15-16 
6-8-9 
10-12 
15-16 

6-8-9 
10-12 
15-16 
6-8-9 
10-12 
15-16 


1,190 
1,027 
919 
987 
925 
750 

525 
509 
371 
542 
369 
292 


4,526 


30 


4,151 


30 


3,197 


36 


3,797 


36 


3,356 


36 


2,928 


Valencia 

30 


3,000 


30 


2,738 


30 


2,071 


36 


2,708 


36 


2,170 


36 ' 


1,771 







• No results reported in 1927. 



Table 9. — Average Acre Yields of Peanuts and Peanut Hay, Arkansas 
Agricultural Experiment Station, Fayetteville, 1931-1934 and 1937-1941". 



Variety and Spacings 


Average acre yield 
1931-34 


Average acre yield 
1931-1934 and 1937-1941 




Nuts 


Hay 


Nuts 


Hay 


Inches 


Pounds 


Tons 


Pounds 


Tons 


Valencia'' 

36 X 8 


1,494 
1,442 
1,284 
1,394 
1,286 
1,230 

2,520 
2,412 
2,277 
2,425 
2,331 
2,213 


2.34 
2.25 
2.08 
2.58 
2.54 
2.28 

2.98 
2.98 
2.94 
3.20 
3.17 
3.31 


1,316 
1,249 

1,395 
1,260 

2,160 
1,873 

2,101 
2,037 


2.03 


36x 12 


1.98 


36 X 16 




30 X 8 


2.25 


30x 12 


2.19 


30x 16 




White Spanish" 

36 X 8 


2 60 


36 X 12 


2.39 


36 X 16 




30 X 8 


2.75 


30 X 12 


2 69 


30 X 16 









» Crop failures in 1935 and 1936 not included, 
b Tennessee Red substituted for Valencia in 1941 , 
• Improved Spanish used in tests, 1937-1940. 



CULTURAL PRACTICES 



181 



Table 10. — Average Yields of Florida Runner and Spanish Peanuts Spaced at 

Different Distances in 30-inch Rows on Norfolk Sand, Experiment Station 

Farm, Gainesville, Florida, 1928-1929 



Variety 


Spacing of 

plants in 

drill 


Yield of nuts per 

acre; average 

1928 and 1929 




Pounds 


Pounds 


Florida Runner 


6 

12 
24 

3 
6 
9 


1,282 


Spanish 


958 
912 

990 




776 
631 



the station (7) conducted spacing tests with both runner and Spanish 
peanuts. The average results for the 2 years are reported in table 10. 
Highest yields were obtained from runners spaced 6 inches and Spanish 
spaced 3 inches in the drill. 

Georgia Coastal Plain Station Results. Average results of spacing 
tests conducted 1930-1936 (14) are reported in table 11. The tests with 
Spanish peanuts were conducted at Tifton. Highest yields were obtained 
from 6-inch hills with rows 18 inches apart. It is reported, however, that 
this width row is harder to cultivate than wider rows and attention is 
called to the fact that such narrow rows and spacing require larger 
quantities of seed. Rows spaced 24 to 30 inches apart with hills 6 inches 
apart are believed to be the most practical for the Spanish variety. 



Table 11.- 



-Average Yields of Spanish Peanuts in Spacing Test at the Georgia 
Coastal Plain Experiment Station, Tifton, 1930-1936 



Spacing 


Yield of unshelled nuts 
per acre 






Between row 


In row 




Inches 


Inches 


Pounds 


36 


3 


1,393 


36 


6 


1,360 


36 


12 


1,212 


36 


18 


1,131 


36 


24 


932 


6 


6 


1,509 


18 


6 


1,561 


24 


6 


1,503 


30 


6 


1,356 


36 


6 


1,139 



182 



THE PEANUT— THE UNPREDICTABLE LEGUME 



North Carolina Agricultural Experiment Station Results. The results 
from spacing tests with various varieties of peanuts conducted at the 
Rocky Mount Station (6) are reported in tables 12 to 15, inclusive. Data 
were obtained on both Virginia Bunch and Jumbo Runner peanuts 
planted in 3-foot rows in hills 4, 8, 12 and 16 inches apart with one and 
two plants per hill. Highest yields were obtained from 1929-1931 (table 
12) where the Virginia Bunch variety was spaced 4 inches apart in the 



Table 12 


— Results of Peanut-Spacing Tests, Upper Coastal Plain Station, 
Rocky Mount, North Carolina, 1929-1931 


Distance 

between 
hills^ 


Plants 
per 
hill 




Hand Picks 


Average 
U.S. 
grade 
and 
class 


Total 
shelling 
Percent 


Yield per acre 


yield 
Per 
acre 


Jumbo 


Total 


Jumbo 
hand 
picks 


Total 
hand 
picks 


Large 

kernels 


Total 

large 

and 

medium 

kernels 


Inches 


Number 


Pdvnds 


Percent 


Percent 




Percent 


Pounds 


Pounds 


Pounds 


Pounds 



V'rginia Bunch 



4 


1 


1,428 


11.2 


31.5 


5A 


65.5 


ISO 


450 


217 


846 


8 


1 


1,227 


15.1 


42.2 


4B 


63.1 


168 


522 


214 


706 


12 


1 


1,163 


15.2 


39.3 


5B 


61.5 


159 


451 


152 


619 


16 


1 


1,114 


14.4 


36.1 


SB 


61.9 


150 


400 


149 


598 


8 


2 


1,390 


15.4 


40.1 


4B 


62.9 


204 


S5S 


234 


791 


12 


2 


1,324 


16.4 


39.5 


5B 


62.2 


206 


526 


184 


734 


16 


2 


1,248 


14.8 


38.2 


5B 


61.7 


173 


480 


185 


688 



Jumbo Runner 



4 


1 


1,695 


29.9 


46.5 


2B 


63.0 


487 


815 


333 


998 


8 


1 


1,700 


32.3 


49.4 


2B 


62.3 


530 


858 


282 


988 


12 


1 


1,793 


36.4 


53.6 


IB 


61.8 


621 


986 


351 


1,007 


16 


1 


1,610 


38.8 


55.5 


IB 


64.0 


601 


923 


310 


954 


8 


2 


1,832 


36.2 


49.4 


IB 


61.5 


633 


901 


353 


1,016 


12 


2 


1,902 


32.3 


53.0 


2B 


63.5 


593 


1,053 


369 


1,144 


16 


2 


1,848 


32.7 


51.3 


2B 


64.4 


597 


1,011 


368 


1,138 



a Rows 3 feet apart. 

drill with one plant per hill. Two plants per hill with hills either 8 inches 
or 12 inches apart produced only slightly less peanuts than the 4-inch 
spacing of this variety. Jumbo Runners produced highest yields when 
spaced 12 inches apart in the drill with two plants per hill. 

In other tests conducted in 1929-1931 and 1936-37 at the same 
location (table 13), approximately equal results were obtained from 
spacings of two plants per hill 8 inches apart, one plant per hill 4 inches 
apart, and two plants per hill spaced 12 inches apart. Wider spacing gave 
much lower yields. 



CULTURAL PRACTICES 



183 



Table 13. — Results of Peanut Spacing Tests, Upper Coastal Plain StatioNi 
Rocky Mount, North Carolina' 



Dis- 








Unshelled nuts 


Shelled nuts 


Total 


tance 
be- 


Plant 
per 


Yield 
per 


Grade 
and 














Shelling 
Per- 






Total 






Total 


tween 


Hill 


Acre 


Class 


Jumbo 


Fancy 


Hand- 


Large 


Medium 


large and 


centage 


Hills 












picks 






medium 




Inches 


Number 


Pounds 




Percent 


Percent 


Percent 


Percent 


Percent 


Percent 


Percent 


4 


1 


1,544 


3B 


18.4 


24.7 


43.1 


14.0 


44.6 


58.6 


64.1 


8 


1 


1,389 


3B 


20.0 


31.1 


51.1 


16.1 


40.5 


56.6 


61.4 


\l 


1 


1,311 


3B 


20.9 


30.6 


SI. 5 


13.3 


40.6 


53.9 


60.4 


16 


1 


1,206 


2C 


22.7 


27.7 


50.4 


13.0 


40.3 


53.3 


59.6 


8 


2 


1,583 


3B 


19.5 


29.1 


48.6 


14.9 


41.3 


56.2 


60.9 


12 


2 


1,532 


2B 


23.7 


28.2 


51.9 


14.0 


41.6 


55.6 


61.0 


16 


2 


1,430 


2B 


21.8 


'27.1 


48.9 


U.7 


40.4 


55.1 


60.5 



» Conducted during seasons of 1929-1931 and 1936-1937. 

In tests at Rocky Mount in 1943 and 1944 (table 14) best yields were 
produced from thick spacing of both North Carolina 31 and Spanish 2B 
varieties. Both varieties yielded most when spaced 4 inches apart in the 
row with rows 18 inches wide. In a test conducted in 1947 (table 15), the 
highest yields from no potash were obtained from hills 4.5 inches apart 
in rows 18 inches wide. In the case of the potash treatment spacing 4.5 
and 9 inches between hills in 18-inch rows and 4.5 inches between hills in 
27-inch rows produced approximately the same yields. 

South Carolina Agricultural Experiment Station Results. Spacing- 
test results at the Pee Dee Station, Florence (3) showed that the highest 
yields were produced where Spanish peanuts were spaced very close in 
the row, the best yields of nuts being obtained from plants spaced 3 inches 
apart in 2.5-foot rows. Table 16 records the average results obtained 
from nuts and forage. 

TaUe 14. — Average Yields of Peant^ts at Different -Spacings in Tests at 
Upper Coastal Plain Station, Rocky Mount, North Carolina, 1943 and 1944 



Distance 

between 

Hills 


Average yields per acre, v 


ariety and row width 


North Carolina 31 




Spanish 2B 




18" 


24" 


30" 


36" 


18" 


24" 


30" 


36" 


Inches 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Founds 


4 

8 

12 

16 


1,974 
1,732 
1,503 
1,353 


1,876 
1,616 
1,506 

1,351 


1,470 

1,377 
1,280 
1,288 


1,358 
1,435 
1,160 
1,069 


1,862 
1,519 
1,339 
1,162 


1,610 

1,439 

1,328 

920 


1,106 

1,175 

1,213 

924 


1,330 

1,320 

1,093 

998 



184 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 15. — Results of Peanut Spacing Tests, Upper Coastal Plain Station, 
Rocky Mount, North Carolina, 1947 



Distance 


Average yields per acre from different spacings with and 
without potash 


Hills 


No potash 


With potash 




18 in. 


27 in. 


36 in. 


18 in. 


27 in. 


36 in. 


Inches 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


4.5 


2,805 
2,399 
2,311 


2,305 
2,218 
2,205 


1,557 
1,558 
1,481 


2,985 
3,135 
2,910 


3,040 
2,506 
2,495 


2 305 


9.0 


l'745 


13.5 


1 943 







L. S. D. (051 Potash-levels, 196 pounds; row width, 306 pounds; row spacings, 189 pounds. 

Texas Agricultural Experiment Station Results. Spacing tests with 
peanuts have been reported from several Texas substations. At Substa- 
tion No. 11, Nacogdoches (12), Spanish peanuts were planted for 
normal stand in 18- and 36-inch rows, 1914-1916. The average yields for 
the 3-year period were 30 bushels of nuts and 0.59 tons of hay per acre 
in the 36-inch rows and 32 bushels of nuts and 0.54 tons of hay per acre 
in the 18-inch rows. 

Average yields from experiments at Substation No. 8, Lubbock (12), 
conducted 1919-1923 and 1925, are given in table 17. Spanish peanuts 
were used in these tests. Highest yields of both nuts and forage were 
obtained from the 6-inch spacing between hills. 



Table 16. — ^Average Yields of Spanish Peanuts Spaced at Different Intervals, 
Pee Dee Experiment Station, Florence, South Carolina, 1917-1919> 



Row 
width 


Spacing in 
rows 


Yield oj peanuts 
per acre 


Yidd of hay 
per acre 


Feet 


Inches 


Pounds 


Pounds 


2)4 


3 
6 
9 

12 

15 

3 

6 

9 

12 

15 


850 
713 
590 
573 
595 

763 
653 
653 
570 

477 


2 023 


3 


2,057 
1,610 
1,693 
1,560 

1,830 
1,657 
1,700 
1,607 
1,420 





a 800 pounds per acre of 2-8-3 fertilizer used 1917 and 1918; 470 pounds per acre used in 1919. 
Shelled peanuts used in 1917 and 1918, and unshelled nuts used in 1919. 



CULTURAL PRACTICES 



185 



Table 17. — ^Average Yields per Acre of Nuts and Forage from Spanish Peanuts 

Planted on Lake Charles Clay and Clay Loam at Different Spacings, 

Texas Substation No. 8, Lubbock, Texas, 1919-1923 and 1925" 





Spacing between plants^ 


6-year average 




Nuts 


Forage 


Inches 


Bushels 


Tons 


6 


49.6 
45.4 
42.0 
39.8 
35.1 


1.78 


9 

12 


1.62 
1.51 


15 


1.20 


18 


1.34 







» No yield shown for 1924. 
■^ 36-inch rows. 



Spacing experiments were conducted at Substation No. 3 at Angleton 
( 16) . Due to the fact that the spacings of plants in the row were variable 
from year to year, only the data from 1916-1918 are reported in table 18. 
The results for other years are in keeping with these data in that the nar- 
row spacings practically always gave the highest yields per acre. Highest 
yields were obtained from the 6-inch spacing. 

Virginia Agricultural Experiment Station Results (2). Recom- 
mends spacing Jumbo and Virginia Runner varieties 10 to 16 inches 
apart in the row with rows 30 to 40 inches apart; and Spanish from 
6 to 12 inches apart in the drill with rows 24 to 30 inches apart. 

Miller (13) found that increased vine growth was obtained where 
runner peanuts were dusted to control diseases and insects. Experiments 
were conducted to determine the spacing between rows that would favor 
the highest yields of peanuts receiving three or four applications of sul- 
fur dust. It was found that the highest yield of good quality nuts was 
obtained from dusted plants that were grown in rows farther apart than 



Table 18. — Average Yields per Acre of Spanish Peanuts from Different 
Spacings of Plants, Texas Substation No. 3, Angleton, Texas, 1916-1918 



Spacing of plants in row 


Average yield of peanuts 




Inches 


Pounds 


6 


2,754 


9 


2,470 


12 


2,493 


18 


2,373 


24 


1,840 







186 



THE PEANUT— THE UNPREDICTABLE LEGUME 



customary. Specific spacing recommendations are not made, bi;t it is 
suggested that rows be spaced at least 32 to 38 inches apart for runners 
with plants spaced several inches wider than the customary spacing in 
the row. 

A very large percentage of the spacing experiments with peanuts 
have been conducted with the Spanish variety. They show that this 
variety yields most in rows 18 to 24 inches apart with plants 4 to 6 inches 
apart in the row. Tests in which the larger bunch types or the runner 
types were used show that they should be planted in 30-inch rows with 
plants 6 to 8 inches in the row. 

Seed per Acre 

Poor stands due to planting an insufficient quantity of seed are one 
of the causes of low yields of peanuts. It is not possible to recommend 
accurately the quantity of peanuts needed per acre because of the extreme 
variations found in the size of seed even within a variety. Parliam (14) 
made counts and calculated the approximate seeding rate shown in table 
19. 

Killinger et al. (7) suggest that 30 to 35 j^ounds of shelled or 50 
pounds of runner seed in the hull are sufficient for planting an acre in 
30- to 36-inch rows where peanuts are to be 6 to 8 inches apart in the 
drill. They suggest 50 pounds of shelled Spanish peanuts for spacings of 
3 to 5 inches apart in 24-inch rows. 

Sturkie (17) recommends 50 to 75 pounds of shelled seed per acre for 

Table 19. — Approximate Quantities of Peanuts Needed to Plant One Acre at 

Different Spacings 









Amount of seed needed at five different ram widths 








Hill 
spac- 
ing 


















Variety 


18-in 


zh row 


24-inch row 


30-inch row 


36-in 


'h rmv 


42-in 


'h rcnv 




























Shelled 


Un- 
shelled 


Shelled 


Un- 
shelled 


Shelled 


Un- 
shelled 


Shelled 


Un- 
shelled 


Shelled 


Un- 

shelled 




Inches 


Founds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Pounds 


Spanish 


3 


89 


215 


67 


161 


55 


129 


45 


108 


_ 


_ 


Spanish 


6 


45 


107 


34 


81 


27 


65 


22 


54 


— 


— 


Spanish 


8 


34 


81 


25 


61 


20 


48 


17 


40 


— 


— 


Spanish 


10 


27 


65 


20 


48 


16 


39 


13 


32 


— 


_ 


Spanish 


12 


22 


54 


17 


40 


13 


32 


11 


27 


— 


— 


N.C. Runner. . 


6 


— 


— 


47 


118 


37 


94 


31 


78 


27 


67 


N.C. Runner, . 


8 


— 


— 


35 


88 


28 


71 


23 


59 


20 


50 


N.C. Runner. . 


10 


— 


— 


28 


71 


22 


57 


19 


47 


16 


40 


N.C. Runner . . 


12 


— 


— 


23 


59 


19 


47 


16 


39 


13 


34 


N.C. Runner. . 


U 


" 


" 


20 


SO 


16 


34 


13 


S3 


11 


29 



CULTURAL PRACTICES 187 

spacings of 3 to 4 inches in 2-foot rows. In 3-foot rows, 25 to 40 pounds 
of seed are needed for spacings of 6 to 8 inches between plants. 

The Alabama Station conducted 23 tests at eight locations, 1943- 
1946, inclusive, and obtained practically perfect stands from planting 90 
pounds of unshelled Spanish seed. Poor germination, covering either too 
shallow or too deep, low vitality, and other factors affect emergence and 
early growth of peanuts. It is usually necessary to plant 20 to 25 percent 
more peanuts than the theoretical quantity necessary to obtain a stand. 

SEED PREPARATION AND TREATMENT 

High-yielding strains and varieties of peanuts are being developed. 
Stock from these improved strains should be obtained by the grower, 
multiplied and used for planting. When the crop is mature, peanuts for 
seed should be harvested during dry weather and placed in small stacks 
around poles as described in another section of this chapter. They should 
be left in the stack for about 4 to 6 weeks before picking. After picking, 
the seed peanuts should be either sacked or stored in bulk in a dry place 
where there is free circulation of air. Peanuts should not be stored in 
sufficient bulk to cause heating. When they are spread rather than piled 
in one large heap, there is less danger of heating. Stored peanuts should 
be protected from mice, rats, insects and other pests. 

Shelled vs. Unshelled Seed 

Both shelled and unshelled nuts are used for planting. The large- 
seeded varieties are practically always shelled before planting, but some 
growers plant the Spanish variety without shelling. 

Tests by the Alabama Station show that unshelled Spanish peanuts 
planted at heavy rates produced good stands and satisfactory yields 
as compared with an equal quantity of seed that were shelled and planted. 
Results of these tests are given in table 20. In the tests 90 pounds of 
seed per acre planted either in the hull or after shelling produced a stand 
of plants averaging approximately 4 inches between hills. In 14 of the 
23 tests, 60 pounds of unshelled seed per acre produced a stand averaging 
5.15 inches between hills. It may be seen that unshelled peanuts gave a 
slightly decreased stand and yield when planted late. These decreases are 
believed to be due to a shortage of soil moisture at the time of the late 
planting, which reduced germination of the unshelled seed. 

In other tegts conducted at Auburn in 1943 and 1944 ( 19) in which 
low-vitality Spanish seed were used, low emergence was obtained from un- 



188 



TttE PEANUT— THE UNPREDICTABLE LEGUME 



Table 20. — Average Number of Plants per 100 Feet of Row and Average 
Yield of Spanish Peanuts when Planted at Different Dates, Using 
Different Rates and Conditions of Seed; Various Locations, Alabama, 

1943-1946" 



Weight of seed 

in shell — 

pounds 

per acre 


Conditions of 

seed 

when 

planted 


Average number of plants per 100 feet of rcmP 


, First 
planting 


Second 
planting 


Thtrd 
planting 


Average all 
dates of 
planting 


90 
90 
135 
Average by 
plantings 


Hand shelled 

Unshelled 

Unshelled 


298 
319 
422 

346 


351 
319 
406 

359 


320 
277 
364 

320 


323 
306 
397 

342 






Average yield in pounds per acref' 


90 
90 

135 
Average by 
plantings 


Hand shelled 

Unshelled 

Unshelled 


1,406 
1,473 
1,425 

1,435 


1,513 
1,471 
1,405 

1,463 


1,236 
1,291 
1,275 

1,267 


1,385 
1,412 
1,368 

1,388 



» First planting was about the date of the last killing frost and varied from March 9 m extreme 
southern Alabama to April 17 in northern Alabama. The other plantings were made at 2-week intervals 
following the first planting. 

>> Average of 23 tests at the eight following locations: Fairhope, Brewton, Headland, Prattville. 
Auburn, Alexandria, Crossville and Belle Mina. 

" Yield data from 14 tests at six following locations: Fairhope, Prattville, Auburn, Alexandria, Cross- 
ville and Belle Mina. 

shelled, hand-shelled and machine-shelled seed. In these tests unshelled 
seed germinated only 58 percent and hand-shelled seed 72 percent. 

In tests by the Georgia Coastal Plain Experiment Station (8), No. 
1 hand-shelled Spanish peanut seed germinated better and yielded more 
nuts than either unshelled or small shriveled seed — often called "pegs." 
Emergence results from various seed types are presented in table 2''.. 



Table 21.- 



-Field Emergence of Spanish Peanut Seed Types, Georgia Coastal 
Plain Experiment Station, Tifton, Georgia, 1942-1944 







Seed typ; 


Year 


No. 1 

hand 

shelled 


No. 1 

machine 

shelled 


Unshelled 


Medium 
pegs 


Small 
pegs 




Percent 


Percent 


Percent 


Percent 


Percent 


1942 


87 
76 
88 


83 
62 
82 


64 
39 
61 


66 

51 
83 


S3 


1943 


40 


1944 


78 







CULTURAL PRACTICES 



189 



Method and Time of Shelling 

One of the first studies on time of shelling peanuts was by Beattie 
and others (3). Hand-shelled seed of seven varieties of peanuts — 
Jumbo, Virginia Bunch, Virginia Runner, African, Valencia, Spanish and 
Improved Spanish were planted at the Pee Dee Station, Florence, South 
Carolina, 1922-1924. Shelling was done about February 10, March 10, 
April 10 and May 10. All seed were planted soon after the last shelling. 
All peanuts were spaced 6 inches apart in rows 32 inches apart. The 
data in table 22 show that there was no consistent decrease in the germin- 

Table 22. — Average Germination of Seven Varieties of Peanuts from Seed 
Shelled in Different Months, 1922-1924 



Variety 



Rate of germination'' 



February 
shelling 



March 
shelling 



April 



May 
shelling 



Percent 



Percent 



Percent 



I Percent 



Jumbo 

Virginia Bunch 

Virginia Runner 

Alabama Runner (African) 

Valencia 

Spanish 

Improved Spanish 



78 
87 
86 
86 
89 
92 
92 



82 
72 
75 
78 
76 
87 
79 



77 
87 
85 
79 
75 
87 
81 



78 
79 
86 
83 
87 
93 
85 



* Fractional percentages omitted. 

ation of peanuts from seed shelled 3 months before planting time and 
that shelled shortly before planting. Seed shelled in December and Janu- 
ary of 1923 and 1924 also germinated as well as seed shelled immediately 
before planting. 

Wilson ( 19) at the Alabama Station found that hand^shelled runner 
peanuts gave the same percentage germination whether shelled 6 weeks, 
3 weeks or 1 day before planting, and gave practically the same per- 
centage when shelled 9 weeks before planting. Similar results were ob- 
tained by the Georgia Coastal Plain Experiment Station (9). Seed 
shelled in January and planted in April produced stands equally as good 
as those shelled and planted in April. 

Prior to World War II nearly all peanuts for planting were shelled 
by hand. Some are still hand-shelled, but this method of preparing seed 
for planting is rapidly decreasing. Labor shortage, labor cost, and the 
fact that hand shelling is a tedious, monotonous operation account for the 
decline of handshelling. 



190 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Machine shelling often breaks the skin on a large percentage of nuts 
and sometimes damages the seed by crushing or breaking the nuts in 
half. This is especially true if ungraded peanuts of uneven sizes are being 
shelled. It is also true with graded nuts, if the machine is not properly ad- 
justed. When the seed coat is broken, seed-rot fungi have easy access to 
the kernel and cause decreased germination. Because of the poor stands 
that have been obtained, machine-shelled seed have often been found 
unsatisfactory. However, improvement in machines used for shelling, ad- 
ditional experience with their operation, and improved seed disinfectants 
have resulted in better germination of machine-shelled seed. Relatively 
small commercial shellers designed especially for handling seed peanuts 

Table 23. — Effect of Time of Shelling and Seed Treatment on the Emergence 
OF Hand-Shelled and Machine-Shelled Runner Peanuts, Main Station, 

Auburn, 1946 



Method of 
shelling 


Seed 
treatment 


Percentage of emergence of plants from seed 
shelled at four different periods prior to planting 


Nine weeks 


Six weeks 


Three weeks 


One day 




None 

2 Percent Ceresan 

None 

2 Percent Ceresan 


Percent 


Percent 


Percent 


Percent 


Hand 

Hand 

Machine 

Machine 


71 
85 
64 
80 


80 
86 
64 
79 


80 

82' 

51 

83 


80 
86 
44 
80 



are now being developed. One such machine known as the U. S. D. A. 
Peanut Sheller described by Brown and Reed (4) shows much promise 
for use by relatively small producers. Using medium-vitality peanuts 
shelled on this, machine and treated, Wilson (19) obtained equally good 
results from hand- and machine-shelled peanuts. These results are re- 
ported in table 23. 

Seed Treatment 

Seed treatment with proper seed disinfectants has been found to 
improve the germination of both hand-shelled and machine-shelled pea- 
nuts for seed. Hand-shelled seed and unshelled seed respond less to seed 
treatment than do machine-shelled seed. In fact, good stands can often be 
obtained from planting the recommended quantities from either hand- 
shelled or unshelled seed without treatment. Treating of hand-shelled 
seed usually results in 5 to 10 percent increase in emergence. Treatment 
of machine-shelled seed, however, often increases the stands by 30 to 50 



CULTURAL PRACTICES 



191 



percent. Wilson (19) of the Alabama Station has tested a number of 
seed-treating materials on Spanish and runner peanut seed. He reported 
that stands were improved by each of several materials used. However, 
some of them gave better results than others. He found that the response 
to seed treatment of Spanish and runners was about the same. 

Results at the Alabama Station (table 24) show the effect of various 
seed disinfectants on emergence of machine-shelled Spanish and runner 
peanuts over a period of 5 years. Treatments with 2 percent Ceresan and 
DuBay 1452-F (IJ^ ounces of the latter to 100 pounds of seed) were two 
of the best. These results are similar to those obtained at the Georgia 

Table Z4. — Effect of Various Seed Disinfectants upon Emergence of Machine- 
Shelled Spanish and Runner Peanuts, Main Station, Auburn, Alabama 



Disinfectant 



Rate of application per 

100 pounds of shelled 

seed 



Average number of 
plants from 100 seeds 



Spanish 



Runner 



Ounces 



Percent 



Percent 



None 

Merc-0-Dust. . .. 

Dow9B .. 

Yellow Cuprocide. 

Spergon 

Arasan 

Phygon 

Ceresan, 2 percent 
DuBay 1452-F... 



3 

3 
4 
4 
3 
2 
4 



48 
69 

65 
66 
71 
62 
78 
86 



58 
67 
71 
73 
79 
83 
80 
87 
85 



Coastal Plain Experiment Station (9) where 2 percent Ceresan, Arasan, 
Spergon, U. S. R. No. 604 and Dow 9B were found to be of value in the 
order named. DuBay 1452-F used at the rate of 3 ounces per 100 pounds 
of seed at the Georgia Coastal Plain Station was toxic to the peanut 
seed. 

The North Carolina Experiment Station (15) obtained quite satis- 
factory results from seed treatment of machine-shelled seed. In some 
cases the percentage of emergence from treated seed has been more than 
twice that of untreated seed. Some results from seed treatment obtained 
by the North Carolina Station are reported in table 25. This Station has 
also conducted tests with Virginia Bunch and Spanish peanuts, in which 
hand-shelled, machine-shelled and unshelled seed of these two varieties 
were treated with Arasan. The results of a representative field experi- 
ment involving this treatment are given in table 26. 

It will be noted that treating machine-shelled peanuts with New 



192 



THE PEANUT— THE UNPREDICTABLE LEGUME 



Table 25. — Results of Two Seed Treatment Tests with Machine-Shelled 
Virginia Bunch Peanuts Conducted in the Field, North Carolina, 1942 



Test' 


Emergence from seed receiving different treatments 


No 
treatment 


New 

Improved 

Ceresan 


Spergon 


Arasan 


Yellow 
Cuprocide 




Percent 


Percent 


Percent 


Percent 


Percent 


A 


61.2 
37.8 
49. S 


80.3 

75.2 
77.7 


92.2 
63.3 

77.7 


82. S 
69.7 
76.1 


60.5 


B 


69.8 


Average 


65.2 







» The seed used in tests A and B were from different sources. The seed were composed of large and 
medium sizes 



Improved Ceresan, Spergon and Arasan increased the emergence in all 
cases. However, Yellow Cuprocide was no more effective than no treat- 
ment in one test. The Arasan treatment of Virginia Bunch and Spanish 
peanuts was effective on both hand-shelled and machine-shelled seed. 
However, there was not much increase in the percentage of emergence 
from imshelled Spanish variety treated with Arasan. 

Results from seed-treatment tests by the Virginia Experiment Sta- 
tion during 1939-1945 showed that the stand of peanuts from machine- 

TaMe 26. — Results of One Representative Field Experiment Conducted to 

Determine Effects of Seed Treatment on Emergence of Peanuts Shelled 

BY Different Methods, North Carolina, 1942 





Variety 


Emergence from seed receiving different 
treatments 




Untreated 


Treated with 
Arasan 






Percent 


Percent 




Hand-shelled 




69.0 
68.5 


76 2 


Spanish 


82 6 










MachinC'Shelled 


Virginia Buncli. . 


39.1 

57.5 


60 7 




71 7 










Unshelled 


Virginia Buncli . . 
Soanish. 


32.5 


39 2 







CULTURAL PRACTICES 



193 



shelled seed can be greatly improved and that the stand from hand-shelled 
seed is slightly improved by treating with such disinfectants as Ceresan, 
Arasan, Yellow Cuprocide, Dow 9, and U. S. R. 604. On high-vitality 
hand-shelled seed, the increase in emergence from treatment is said to 
average about 5 percent, whereas on seed of low vitality, the increase is 
proportionately larger. Treatment of high-grade machine-shelled seed, 
however, increased the stand by 20 to 35 percent. With low-vitality, ma- 
chine-shelled seed the increase in some cases amounted to many times 
this percentage. High-vitality machine-shelled seed when treated with a 
good disinfectant gave about as good a stand as untreated hand-shelled 
seed of the same lot. Data from which some of these conclusions were 
drawn are given in tables 27 and 28. 

Seed may be shelled and treated during the winter months when labor 



Table 27. — Average Number of Plants Obtained from 100 Seed Planted in 
Seed-Treatment Test, Holland, Virginia, 1943-1944 



Treatment, per 100 pounds of seed 



Average number of plants from 100 seed 



Hand-shelled 
seed 



Machine-shelled 
seed 



Arasan, 3 oz 

Arasan, 2 oz 

Ceresan, 4 oz 

Ceresan, 3 oz 

Yellow Cuprocide, 4 oz 
Yellow Cuprocide, 2 oz 

Spergon, 4 oz 

Spergon, 2 oz 

Untreated 




91 
91 
93 
95 
90 
87 
85 
83 
63 



Table 28. — Average Number of Plants Obtained from 100 Seed Planted in 
Seed-Treatment Test, Holland, Virginia, 1945 



Treatment per 100 pounds of seed 



Average number of plants from 100 seed 




U. S. R. 604, 2 oz 

Ceresan, 4 oz 

Dow 9, 2 oz 

Yellow Cuprocide, 4 oz 

Arasan, 3 oz 

Spergon, 4 oz 

Fermate, 3 oz 

Dow 9 B, 2 oz 

Untreated 



194 THE PEANUT— THE UNPREDICTABLE LEGUME 

is available. In tests conducted at Auburn ( 19) , seed shelled and treated 
9 weeks before planting have produced stands as good as those shelled 
and treated 1 day before planting. These tests have been in progress for 
3 years. In no instance has there been any significant difference in the 
stands obtained from seeds shelled on the different dates and treated im- 
mediately. The results given in table 23 were obtained in 1946 ; they are 
in agreement with those obtained in earlier years in other tests. 

After the seed are shelled and treated, they should be stored in a dry 
place. Under such conditions they will keep for several months. Seed 
shelled, treated and stored in screened cages at Auburn have germinated 
as well IS months after shelling as they did at the time they were 
shelled. Usually, though, it is impractical to carry treated seed over from 
one year to another because of web-worms that get into seed. 

The method used to apply the disinfectant will depend upon the 
volume of seed to be treated. Whatever method is used, it should insure 
uniform distribution of the disinfectant over every seed. For best results 
each seed should be coated with a film of the chemical dust. Some dis- 
infectants will vaporize, and the vapors that enter the sack of seed will 
kill the disease-producing organisms on the seed. However, such seed 
will become recontaminated as soon as they are placed in the ground, 
unless they are covered with a protective coating of the disinfectant. 
Thorough coverage is especially important on machine-shelled seed to 
prevent entrance of seed-rotting organisms through breaks in the seed 
coat. 

INOCULATION 

Inoculation of peanuts with strains of nitrogen-fixing bacteria has 
given varied and inconsistent results. Consequently, many stations do not 
recommend use of artificial inoculation. Apparently, many soils carry the 
necessary nodule bacteria for this crop. Hence, artificial inoculation 
rarely has much effect on yield. 

Small increases were obtained by the Alabama Station (1) from the 
use of inoculation the first year that peanuts were grown in localities 
where the crop was not generally grown. The average results of tests 
conducted on Norfolk soil at different locations in 1940 and 1941 are 
giveji in table 29. The data show that the effect of inoculation on Spanish 
peanuts was much accentuated by the use of mineral fertilizers applied 
in the drill before planting. Also, fertilizers were more effective on this 
soil in the presence of inoculation. It was observed that the plants that 
grew on the fertilized plots carried substantially more tubercles than the 
plants on the unfertilized plots. 



CULTURAL PRACTICES 



195 



Table 20. — Influence of Inoculation and of Fertilizers on Hay and Nut 
Yields of Spanish Peanuts, Main Station, Auburn, Alabama, 1940-1941 



Fertilizers per acr^ 




Inoculation 


Yields per acre 


Hay 


Nuts 




Pounds 




Pounds 


Pounds 


None 


320 
50 

320 
50 


+ 
+ 


1,504 
1,493 

1,408 

1,702 


1 102 


None 


1 117 


Superphosphate 




Muriate of potash 


1 097 


Superphosphate 




Muriate of potash 


1 281 







■ Fertilizers applied in row before planting 70 pounds of shelled nuts per acre. 

In other Alabama experiments conducted on the Coosa Valley soils 
of the Decatur, Etowah and Fullerton series on the Alexandria Experi- 
ment Field, peanuts were planted with and without inocculation in 1941. 
The land used had not grown peanuts prior to that year. Both Spanish 
and runner were planted on six different areas. The yields of both nuts 
and hay of each variety were increased by inoculation to the extent of ap- 
proximately 100 pounds per acre. The results of this test are recorded in 
table 30. 

Most of the chemical treatments used to prevent diseases also kill in- 
oculating bacteria, thus rendering artificial inoculation useless. Albrecht 
found that Spergon seemed to be an exception to this rule. In tests con- 
ducted in 1943 with machine-shelled peanuts, inoculation of Spergon- 
treated seed produced approximately 14 percent better stands than un- 



Table 30. — Average Yields of Spanish and Runner Peanuts Grown with and 
WITHOUT Inoculation, Alexandria Experiment Field, Alabama, 1941 





Yield per acre 


Treatment 


Spanish 


Runners 




Peanut 


Hay 


Peanut 


Hay 




Pounds 


Pounds 


Pounds 


Pounds 




1,321 
1,208 


1,691 
1,552 


1,508 
1,378 


2,970 




2,870 






Increase from inoculation 


114 


139 


130 


100 



196 



THE PEANUT— THE UNPREDICTABLE LEGUME 



inoculated seed treated with Spergon. The per-acre yields in favor of 
inoculation in the presence of Spergon treatment are : 

2161 pounds of hay 
1303 pounds of nuts 



Spergon-treated, inoculated, 
Spergon-treated, uninoculated, 
Increase from inoculation, 



1825 pounds of hay 
1170 pounds of nuts 

336 pounds of hay 
133 pounds of nuts 



CULTIVATION 

First cultivation of peanuts consists of running a weeder or rotary 
hoe in the same direction as the rows. Successive weedings are made with 
the rows or diagonally across the rows and are continued until the plants 
are large enough to be broken by such an implement. The practice of 
broadcast cultivation is very important in producing peanuts with a 
minimum of hoeing. A weeder may be operated following a rain 2 to 3 
days before the soil is sufficiently dry to permit plowing. Thus, weeds 
may be killed in the seedling stage. 




Sl« ■> -' .;.?*!' 



Figure 2. — Tractor-drawn weeder. 



CULTURAL PRACTICES 



197 




Figure 3. — Tractor-drawn rotary hoe. 







Figure 4. — One-horse cultivator. This type implement carrying sweeps is 
largely used after the first cultivation. 



Later cultivation consists of cultivating shallow with sweeps or other 
shallow cultivation implements run in the same direction as the rows. 
Little or no soil is turned toward the plants except at the first cultivation. 
Pegs (pins or young pods) should never be torn loose. The middle should 
be kept clean until the vines cover sufficiently to smother weeds. 

The principal object in cultivation is to prevent growth of weeds and 
grass, which are especially harmful because they reduce yield and greatly 
increase labor in harvesting. In fact, very weedy peanuts are nearly im- 
possible to harvest. Another object of cultivation is to keep the soil loose 
so that the ovary of the seed stem can pierce the soil readily and thus 
allow the nuts to form. 



198 THE PEANUT— THE UNPREDICTABLE LEGUME 

The practice of covering the young pegs with soil to insure their 
pegging down is unnecessary and often is harmful, since it destroys some 
of the foliage. 

Runner peanuts are usually so cultivated as to leave the land flat. 
Spanish or bunch peanuts are cultivated in such a way as to leave the 
plants on a bed at the time of laying-by. 

Hoeing is necessary in most cases. In favorable years, rapid and 
frequent cultivation will destroy all weeds and make hoeing unnecessary. 
If peanuts become weedy or grassy, the weeds or grass should be re- 
moved immediately. Removal of weeds or grass after the pods begin to 
form is difficult and frequently injures the peanuts. The hoeing operation 
consists of hoeing the plants when small to remove weeds and grass. 
Another hoeing, which consists of "bunching" or removing the bunches 
of grass that have been missed during the season, is done at or just before 
laying-by. The first hoeing operation is quite expensive, usually because 
less than an acre per day can be hoed by one man. The bunching opera- 
tion is much less expensive, since one man can cover several acres a day. 

Dusting 

(Detail of life history and of experiments dealing with control of insects 
and diseases are discussed in later chapters'.) 

Two major groups of peanut pests are insects and diseases. Two 
major insects attacking peanuts are leaf -hopper's and velvet bean cater- 
pillars. The two important diseases that attack peanuts are Cercospora 
leafspot and Sclerotium, or southern blight. 

The use of dusting sulfur, copper sulfur, and combinations of these 
with coijipatible insecticides, such as DDT and Toxaphene, are dis- 
cussed in chapters on insect and disease control. 

Spray treatments have been used and various spray schedules have 
been developed. Use of sprays has been considered impractical for the 
following reasons: 

( 1 ) More time is required to mix and apply the spray than is required 
to dust. 

(2) Costs of spray machinery and materials are higher than the 
costs of dusters and materials. 

(3) There is a greater possibility of burning the foliage by improper 
use of spray than by dusting. 

(4) Frequently, there is not an adequate supply of water available. 

Dusted peanuts are usually dug from 1 to 2 weeks later than undusted 



CULTURAL PRACTICES 199 

plants. The color of the dusted peanut vines is frequently darker than 
the undusted plants. For this reason, it is very important that the time of 
digging be determined by examination at maturity of the nuts rather 
than appearance of the foliage. 

Dusting results in larger yields of peanuts and vines, and in better 
quality nuts and hay. 

Machinery 

Numerous machines are available for dusting. For large-scale opera- 
tions, dusting with tractor power take-ofif equipment is most suitable. In 
the case of smaller acreages, mule-drawn dusters of the one-horse type 
are preferable. For only a few acres, hand dusting with the small hand- 
operated duster is satisfactory. For best results there should be a dis- 
tributor (duster nozzle) over each row. 

HARVESTING 

The peanut plant has a fruiting period covering about 2 months. All 
pods do not ripen at the same time. Thus, it is diiificult to tell just when 
the crop should be dug. If digging is done in time to save the earlier 
formed pods, then the later ones will be immature. On the other hand, if 
digging is delayed, many of the early-formed pods of Spanish peanuts will 
sprout and those of runners and Virginia Bunch are pulled off and left 
in the soil. The principal object is to dig the crop at a stage when the 
largest number of mature pods can be saved and when the weather is 
suitable for curing. If the weather is unsuited for curing, the peanuts 
cannot be harvested regardless of the stage of growth. Frequently, insects 
destroy the foliage and make digging immediately necessary in order to 
save the crop. 

The usual method of determining when to dig is to examine the crop 
frequently as digging time approaches. At intervals of a few days plants 
should be pulled and the stems and pods carefully examined. If many 
of the stem^.. have j^t^rted to decay, digging should be started at once. 
An examination of the pods will show whether or not the pods are ripe. 
When a peanut is ripe, the veins of the hulls are prominent and the in- 
side of the hull has turned dark. If the inside of the hull is white, the 
pod is immature. Another indication of time to dig is that of slight yellow- 
ing of the foliage. The leaves become spotted and some of the leaves begin 
to drop. 

A large amount of labor is required for digging peanuts. Therefore, the 
harvest period usually extends from 2 to 3 weeks. This usually means that 



200 



THE PEANUT— THE UNPREDICTABLE LEGUME 



some of the peanuts are dug before the crop is entirely ripe and the last 
of the crop is dug after the crop is over-ripe. 

Usually it is more difficult to determine when to harvest runner pea- 
nuts than is the case with Spanish. The runner peanut may set a crop of 
fruit and if conditions become favorable, a new crop of fruit is set on the 
ends of the vines. When such a condition occurs, it is necessary to decide 
whether to harvest in order to save the first crop of fruit or to delay 
harvest and save the second crop. If the second crop appears to be the 
larger, it is usually better to delay harvest and save the later crop. The 
pods that were formed early will be left in the soil, but these can be 
utilized by hogs, and therefore are not lost. 

There are many types of 
machines used in digging pea- 
nuts that work satisfactorily. 
None of the machines are ef- 
ficient unless the crop is free 
of grass and weeds, which 
clog the implements and 
make digging difficult. The 
most common type of imple- 
ment used in digging bunch- 
type peanuts is a mold board 
plow with a long point at- 
tached. This cuts the main 
root and loosens the soil. 

For runner peanuts a long 
flat bar sharpened and at- 
tached to a cultivator is used to run underneath the vines. Peanut-digging 
plows with finger like bars that lift the vines from the soil are in use. 
Many of the modern diggers are of a 2-row tractor-drawn type. 

Another type of digger, somewhat like a potato digger, is coming into 
use. This implement lifts and shakes the vines, and leaves them on top 
of the ground— all in one operation. A more recent type of digger, when 
tractor-drawn, lifts, shakes and puts together two rows at a time, leaving 
the vines on top of the ground. 

After the peanuts are plowed up, they are allowed usually to wilt for 2 
to 8 hours before they are stacked. It is customary to windrow the peanuts 
to facilitate stacking either before or after they are wilted. Windrowing 
and shaking may be done by hand, by side delivery rakes, or by special 
machinery. In any case the peanuts should be shaken as free of dirt as pos- 




Figure 5. — ^Turn plow-type peanut digger. 



CULTURAL PRACTICES 



201 







\ 



\ 



Figure 6.— Bar on two-horse cultivator for plowing up peanuts. 




Figure 7.— Tractor with digger blades; 



202 



THE PEANUT— THE UNPREDICTABLE LEGUME 




Figure 8.— After windrowing with side-delivery rake peanuts are left to dry. 




Figure 9.— Tractor equipped with digger blades and mechanical shaker for handling 
two rows at once. 



CULTURAL PRACTICES 



203 




Figure 10. — Shaking and windrowing peanuts by hand. 








■#^ 



Courtesy U. S. Department of Agriculture 

Figure IL — Shaking and windrowing peanuts with side-delivery rake after plowing 
them up with tractor digger blades. 



204 THE PEANUT— THE UNPREDICTABLE LEGUME 

sible. The windrows may be combined into one large row for about 
every 10 to 14 rows. 

Stacking is usually practiced in most of the peanut belt. It is done as 
soon as the plants are wilted and before they are dry enough to be brittle. 
If left on the ground very long, dew and sunlight tend to discolor the pods, 
and the leaves lose the green color and may shatter, which lowers the 
hay quality. The vines are stacked around poles, which are firmly placed 
in the ground so that the stack will not blow over. The poles are usually 
2 to 4 inches in diameter and about 8 feet tall. The poles are placed in the 
ground about 18 inches deep. Greater depth makes it difficult to pull up 
the poles at picking time. If a shallower depth is used, the poles may blow 
over. Two slats, about 3 feet long for runners and about 18 inches long for 
Spanish, are nailed at right angles to the poles 14 to 18 inches above the 
ground. The slats form two crosspieces on which the first layer of vines is 
placed. The crosspieces prevent the vines on the bottom of the stack from 
resting on the ground and allow air to circulate, thus facilitating drying. 
The center of the stack must be kept open and higher than the edges. The 
pods cJf the bunch type of peanuts are placed toward the center. The 
runner types are usually placed on the poles with pitch forks and no at- 
tempt is made to place the nuts so that they are not exposed. Twelve to 
14 rows of peanuts are placed in the stack row and a sufficient number of 
poles are allowed to take care of the stack row. The distance between 
stacks will depend on the amount of peanuts on the ground and usually 
will vary from 40 to 50 feet. Successive layers of vines are placed on the 
stack pole. As the stack nears completion, it is gradually drawn to a point 
and a few vines are pressed down over the top to complete the stack. A 
little dry grass frequently is placed on top of the stack to help shed water. 
In some cases paper or other type of covering is used. 

Peanuts are as a rule stacked in the field where the crop is grown, 
but sometimes the vines are hauled to a central point where the stacks 
are built close together. 

The number of poles required per acre is shown in table 31. 

The practice of field curing in the windrow is quite common in the 
southwestern producing areas. In the Southeastern States it is also some- 
times used. In some instances, it is modified by putting the vines in small 
cocks. The practice works fairly well if weather conditions are favorable 
for curing, but serious damage may occur if there is much rain before the 
crop is dry enough to pick. When this system is used, there is always a 
discoloration of the pods and the hay is of little value. In the Virginia 
and North Carolina area, this system is not used because in those areas 



CULTURAL PRACTICES 



205 



Table 31. — Number of Stack Poles Required with Row Widths and Number 
OF Rows per Stack as Indicated; Claculated on Basis of 40 feet between 

Poles 





Number of rows per stack 




7 


10 


11 


12 


14 




Poles 
per acre 


Poles 
per acre 


Poles 
per acre 


Poles 

per acre 


Poles 
per acre 




Spanish and Improved White Spanish 


24 inches 


— 


54 
49 
44 


50 
45 
40 


45 
40 
36 


39 


27 inches 


35 


30 inches 


31 






, 




Virginia Bunch Type 




iZ inches 


57 
52 


39 
36 


— 


— 




36 inches 









there is little demand for peanuts with even slightly damaged kernels. 
More recently experiments have been conducted in picking the pea- 
nuts green and drying them artificially. Machines for digging and pick- 
ing are available. The practice is not yet common and there are not 
enough available data to indicate how economical it may be. This method 
oilers a possibility of reducing the amount of labor involved in harvesting 




Figure 12. — Stack pole properly set for stacking runner peanuts. 



206 THE PEANUT— THE UNPREDICTABLE LEGUME 




Figure 13.— Peanut stack about one-third completed. The stack should be firm 
throughout with flat top and straight sides until capping is done. 




Figure 14.— Completed peanut stack. Note heavy capping well above end of stack 
pole. 



CULTURAL PRACTICES 207 

peanuts and of standardizing tiie quality. If it can be done economically 
and a satisfactory product produced, it will undoubtedly revolutionize pea- 
nut growing. 

Picking. Peanuts are cured in a period of 4 to 6 weeks in the stack. In 
windrows this period is reduced to about 2 weeks. The peanuts are 
properly cured when the stems have become brittle enough to be broken 
up and blown out, and when the kernels will split open when rolled be- 
tween the fingers. There are two types of peanut pickers : One with a 
cylinder similar to a grain thresher and the other a metal mesh with steel 






Figure IS. — Runner peanuts about 3 weeks after stacking. An excellent 
stack in foreground. Fair stack at right, and poor stack at left. Note 
that bottom of stack has settled away from the capping in the poor 
stack. This is the usual result of loose stacking. 

teeth that tears the vines to pieces but has no cylinder. With either 
type the peanut vine is thoroughly torn apart and the nuts cut from the 
stems and vines by a series of revolving saws. The stacks are hauled to 
the picker behind a specially rigged cart, on fiat-bottom wagons, on a 
"dolly" or sled. In case wagons are used, usually one is being loaded with 
stacks while another is being unloaded at the picker by feeding the pea- 
nuts into the picker. 

In operation of the picker, care must be taken not to feed the machine 
so rapidly that the pods are not cleaned properly. If the machine is 
operated too fast, many of the nuts are forced out with the hay. The speed 
of the fans and the picking machinery must be adjusted carefully so as 
to take care of the particular lot of peanuts being picked. 

In many cases peanuts are custom picked and there is a tendency to 



208 THE PEANUT— THE UNPREDICTABLE LEGUME 

rush the job, which results in loss of nuts in the hay and an unnecessary 
amount of trash is in the nuts. Only dry pods should be picked. Damp 
weather causes difficulty in picking. 

After the peanuts are picked, they should be stored thinly or stirred 
from time to time until dry. Peanuts should not be stored in bulk until 
they are fully dry. 

Peanut hay is a valuable by-product of the peanut crop. Its quality 
depends on proper harvesting date and method, and also on proper curing 
and picking. The hay should be baled immediately after threshing. 

Hay left in the field after threshing is exposed to weather and rapidly 
deteriorates. Usually hay from vines treated with sulfur to control leaf 
spot is higher in quality than that from untreated plants. The amount of 
hay varies with the variety and general conditions. Spanish peanuts 
usually yield from 1 to 1^ tons of hay per ton of nuts, and runner peanuts 
1^ to 2 tons per ton of nuts. 

Many peanuts are grazed by hogs each year in the Southeastern 
States. Hogs are used to glean the fields. Frequently peanuts are planted 
with alternate rows of corn and peanuts are hogged off after the corn is 
harvested. In many instances peanuts are planted solid for hogging. In 
most cases the runner-type peanut is used for hogging. The Spanish is 
earlier than the runner and is used for early hogging, usually from the 
middle of August to the first of October. Runner peanuts remain in good 
condition in the ground much longer than Spanish. They are usually 
hogged from October through January or February. The yield of pork 
per acre varies with the time of harvesting. Early in the season from 2J^ 
to 3 pounds of peanuts are consumed per pound of pork. As the season 
advances the pounds of increased growth per pound of peanuts decreases 
until in February the figure may become as low as from 5 to 6 pounds of 
peanuts per pound of pork. 

Hogs should not be turned on the peanuts until the majority of the 
nuts are ripe. Hogs do not like immature peanuts and usually will not eat 
them. Therefore, if the hogs are turned on when the peanuts are too 
green, they root up many of the vines and waste the immature nuts. 
Hogs do not like decayed nuts and will not eat them if they can get any- 
thing else to eat. 



CULTURAL PRACTICES 209 

SELECTED REFERENCES 

(1) Albrecht, H. R. 

1944. factors influencing the effect of inoculation of peanuts grown 
ON NEW PEANUT LANDS. Soil Sci. Soc. Proc, Vol. 8. 

(2) Batten, E. T. 

1943. peanut PRODUCTION. Va. Agr. Expt. Sta. Bui. 348. 

(3) Beattie, J. H., HuNN, C. J., Miller, F. E., Currin, R. E., and Kyzer, E. D. 

1927. effect OF PLANTING DISTANCES AND TIME OF SHELLING SEED ON PEANUT 

YIELDS. U. S. D. A. Bul. 1478. 

(4) Brown, O. A. and Reed, J. F. 

1944. Agricultural Engineer. Vol. 25, No. 11. 

(5) FuNCHESS, M. J. AND TiSDALE, H. B. 

1924. Ala. Agr. Expt. Sta., Thirty-Fifth Ann. Rep. 

(6) Gregory, W. C. 

1948. No. Car. Agr. Expt. Sta. private communication. 

(7) Killinger, G. B., Stokes, W. E., Clark, F., and Warner, J. D. 

1948. peanuts in Florida. Fla. Agr. Expt. Sta. Bul. 432. 

(8) King, Geo. H. 

1944-45. Silver Anniversary Rept. Ga. C. P. Agr. Expt. Sta. 

(9) 

1945-46. Twenty-Sixth Ann. Rept. Ga. C. P. Agr. Expt. Sta. 

(10) McClelland, C. K. 

1931. the peanut crop in Arkansas. Ark. Agr. Expt. Sta. Bul. 263. 

(11) 

1944. peanut production experiment. 1931-41. Ark. Agr. Expt. Sta. Bul. 

448. 

(12) McNess, George T. 

1928. peanuts in texas. Texas Agr. Expt. Sta. Bul. 381. 

(13) Miller, Lawrence L 

1942. peanut leafspot and leafhopper control. Va. Agr. Expt. Sta. 
Bul. 338. 

(14) Parham, S. a. 

1942. peanut production in the coastal plain of GEORGIA. Ga. C. p. 

Expt. Sta. Bul. 24. 

(15) Shaw, Luther. 

1943. why^ and how to treat peanut seed. N. C. Agr. Ext. Ser. War 

Series Bul. 18. 

(16) Stansel, R. H. 

1935. peanut-growing in the gulf coast prairie of TEXAS. Texas Agr. 
Expt. Sta. Bul. 503. 

(17) Sturkie, D. G. 

1934. PEANUTS. Ala. Agr. Expt. Sta. Leaflet No. 5. 

(18) West, H. O. 

1942. PEANUT PRODUCTION. Miss. Agr. Expt. Sta. Bul. 366. 

(19) Wilson, Coyt. 

1948. seed treatment of peanuts. Ala. Agr. Expt. Sta. Leaflet 23. Revised. 

(20) WiNGARD, S. A. AND BATTEN, E. T. 

1945. TREAT seed PEANUTS FOR PROFIT. Va. Agr. Expt. Sta. Bul. 382. 



CHAPTER VII 



INSECT PESTS 



By 
FRANK SELMAN ARANT' 



The importance of insect damage to peanuts has not been generally 
recognized, even by the peanut industry and agricultural leaders. Text- 
books of economic entomology barely mention peanut insects, although 
numerous species of pests attack the crop in the field and in storage. 
These insects feed on the foliage and underground parts of the growing 
plants, suck the juices of pods curing in the field, and infest peanuts and 

their products in storage and in 
transit to markets. 

The control of insect pests of 
peanuts is a serious problem. 
Scores of species attack peanuts 
throughout the world, and per- 
haps a dozen are of major im- 
portance in southeastern United 
States. Information on the con- 
trol of some of these forms is 
sparse and in some instances the 
economic status is controversial. 
It is the purpose of this chapter 
to summarize the available in- 
formation on peanut insects and 
to point out the need for addi- 
tional information. Major em- 
phasis is on destructive forms 
and species of controversial 
status in southeastern United 
States. 

Department of Zoology-Entomology, Alabama Polytechnic 




Figure 1. Velvetbean caterpillar and fall 
armyworm ragging the foliage of pea- 
nuts. (The larva nearer the fingers in 
the picture is the fall armyworm.) 



^ Frank Selman Arant is iiead, 
Institute. 



210 



INSECT PESTS 211 

Velvethean Caterpillar '^ 

Importance. The velvethean caterpillar, Anticarsia gemmatilis 
(Hbn.), is a serious pest of peanuts in Alahama, Florida and Georgia, 
where it appears to be increasing in importance. During the past 10 years 
some damage from this insect has occurred locally each year, and severe 
outbreaks over the peanut-growing sections of these States were recorded 
in 1939, 1944, 1946 and 1948 (65, 52, 6, 7). Prior to this time the insect 
had been considered of little or no importance on peanuts, although it 
had received some attention on other crops. 

A. gemmatilis damage to velvetbeans in Florida in 1903 was described 
by Chittenden (28). For several subsequent years, damage from the 
insect appears to have been observed primarily on velvetbeans. In 1918, 
Watson (149) reported A. gemmatilis attacked peanuts only when the 
crop was grown adjacent to velvetbeans, and stated that the adults hacj 
never been known to oviposit on peanuts under natural conditions. 
Later Watson (153) reported extensive velvethean caterpillar damage 
to peanuts and soybeans. Additional damage to crops has been listed by 
others (46, 73, 65, 50, 122). Purswell (122) concluded that the insect 
causes economic damage to peanuts, soybeans, kudzu, alfalfa and velvet- 
beans, and also attacks cowpeas, string beans, lima beans, sesbania, black 
locust, horse bean and cotton. Severe damage to crops has been reported 
from Alabama, Florida, Georgia, Louisiana, Mississippi, North Carolina, 
South Carolina and Texas. 

The velvethean caterpillar feeds upon the leaves of peanuts. Heavy 
infestations cause complete defoliation of the plants, including destruc- 
tion of terminal buds. The yield of peanuts is reduced and additional 
losses result from the shedding of pods in the soil at harvest ( 52, 6) . The 
yield of hay is also reduced. 

Reliable data on losses from velvethean caterpillar are difficult to 
obtain. In 1944, the estimated loss in Alabama was placed as high as 10 
million dollars, approximately one-third the value of the crop in the State 
(122). In 1946, the loss in Georgia was estimated at 4 million dollars, 
and the saving resulting from control at nearly 10 million dollars ; in Ala- 
bama the loss was estimated at 500 thousand dollars and the saving from 
control at over 5 million dollars.^ The extent of control operations in 
Alabama is indicated by the fact that approximately 4 million pounds of 
cryolite and 300 thousand pounds of other insecticides were applied in 
1946. 

' Estimate compiled by U. S. Bureau of Entomology and Plant Quarantine. 



212 THE PEANUT— THE UNPREDICTABLE LEGUME 

Description of Stages. Descriptions of the stages and notes on the ap- 
pearance of velvetbean caterpillar have been published by several writers. 
The descriptions of immature stages given below are by Watson (148) : 

Egg 

The egg is nearly 2 mm. in diameter and somewhat less in height, and flattened 
on its lower^ surface. It is prominently ribbed and white until about a day before 
hatching, when it turns a delicate pink. . . . The eggs are laid singly, mostly on the 
underside of the leaves, although many are found on the upper surfaces and some on 
the petioles and stems. 

Larva* 

First Instar. The newly hatched caterpillar is about 2.S mm. long and grows 
to be from 6 to 7 mm. before molting. The head is light brown in color, rounded, 
bilobed ; mouth shining ; eyes black. The body is of a uniform light green color with- 
out any trace of longitudinal stripes. The tubercles are black and conspicuous ; setae 
also black. The prolegs on abdominal segments 3 and 4 are about equal in size but are 
much smaller than those on segments 5 and 6 and are not used for walking. A glance 
at the prolegs is the most ready means of distinguishing the first and second instars. 
The legs are light brownish yellow. 

Second htstar. The markings are now very similar to those of the next instar but 
are somewhat less pronounced. The most conspicuous longitudinal mark is the black 
border to the lateral line. The papillae are black as in the first instar, but there is 
around the base of each a light-colored ring. The first pair of abdominal prolegs, as 
in the first instar, is less than a fourth as long as the third, weak, and not used in 
walking or clinging ; but the second pair is about half as long as the third. These, too, 
are ordinarily not used in walking but occasionally are so used. 

Third Instar. Head rather square in outline, strongly bilobed, yellowish; ocelli 
black; mouth dark brown. Body cylindrical; all prolegs used for walking, but the 
first pair may be somewhat shorter than the others, light yellow; dorsal line pale 
white, somewhat broken, margined on each side by a darker border. Subdorsal line 
very pale and indistinct, bordered as dorsal line ; lateral line indistinct and broken, 
narrow, pale white. Substigmatal line wider and continuous but of a paler color than 
dorsal and subdorsal. Ventral surface yellowish green. Stigmata brown. Tubercles 
black. 

Fourth Instar. Dorsal, subdorsal and sub-stigmatal lines more distinct than in 
the third instar. All feet used in walking, but the first and to a lesser degree the sec- 
ond pair noticeably shorter than the others. Otherwise this instar is very like the 
third. 

Fifth Instar. Also similar to the third instar, but the longitudinal lines are more 
clearly defined. Papillae are now white with brown apexes. In the area between the 
dorsal and subdorsal lines there are a few white dots with a brown border. One of 
the largest of these is situated near the anterior border and subdorsal line on abdom- 
inal segments 1-8. On the metathorax it is double. Stigmatal line is brownish yellow, 
broken, widely bordered with white on the ventral margin. In the lighter colored 
individuals this line is often a rich yellowbordered by lines of deep pink. 

3 Surface attached to the leaf. 

* The description given is of the dark phase. As pointed out by Guyton (65) and others, great 
variation in color occurs after the first instar. The vigorous manner in which the larva wiggles 
upon being disturbed is an important distinguishing characteristic in the field. 



INSECT PESTS 213 

Sixth Instar. The stigmatal line is colored like the lighter forms of the fifth 
instar, but the pink is usually replaced by brown. 

Pupa 

Brown in color, smooth and shining. Abdominal segments punctuated with fine 
dots which are particularly thick on the anterior half of each segment. Head some- 
what pointed. At the end of the abdomen are three pairs of hooked spines, one pair is 
much larger than the others. Length 18-20 mm., width 4-6 mm. The pupa is light 
green until it is about a day old. 

Adult 

No entirely adequate description of the adult has been found. A de- 
scription based on reports of Chittenden (28), Watson (148), Douglas 
(46), and observations of the writer follows: 

The moth averages approximately 37 mm. across the outstretched wings from tip 
to tip. The body is stout and narrowed at the apex, measuring approximately 12 mm. 
from head to tip of abdomen. The color varies from grayish tan to dark reddish 
brown. Under a hand lens the wings have a peppered appearance, black specks show- 
ing on a lighter surface. A line which may be lighter or darker than the rest of the 
wing extends diagonally across the outstretched wings from near the anterior distal 
tip of the forewing to the mid-posterior margin of the hind wing. When the wings 
are at rest this line may appear as the segment of a circle. The part of the wings 
distal to the line is darker than the proximal part. The wings are bordered with a 
brown or yellowish line and are heavily fringed with gray or brown. On the under 
side of the wings is a row of white dots, consisting of 7 dots on each wing. This color 
pattern is less variable than that on the upper surface. In the field, a character of 
value in recognition of the moth is its rapid, spasmodic flight. When disturbed it 
rises quickly, flies rapidly a short distance, and settles suddenly into the foliage of 
the host plant. 

Biology. Life-history studies of the velvetbean caterpillar have been 
made by numerous authorities (148, 46, 73, 122), but many facts con- 
cerning the biology of this species are still unknown. Apparently the in- 
sect does not overwinter in the United States except in southern Florida. 
Watson ( 148) recorded the presence of adults in southern Florida as early 
as May 1 and found the northward flight of the moth reached southern 
Georgia and Alabama by September 1. Subsequently, other investigators 
have observed the northward migration of moths during the sumiTier 
months and it has been assumed that overwintering occurs only in 
southern Florida, Cuba and nearby islands. During recent years, the in- 
creasing damage and early appearance of the insect in southern Alabama 
and Georgia have led to some speculation as to whether the species is be- 
coming acclimated to a more northern habitat. Attempts to carry imma- 
ture and adult stages overwinter at the Wiregrass Sub-experiment Sta- 
tion in southeastern Alabama have been unsuccessful two successive 
winters ( 5) . Thus it appears that overwintering does not occur as far north 



214 THE PEANUT— THE UNPREDICTABLE LEGUME 

as the Wiregrass Station, although larvae have been collected in neai'by 
Houston County as early as June 21 (6). The northern limit of the 
species' overwintering range is not known. 

The moth of the velvetbean caterpillar is active principally at night or 
during twilight. Large numbers in flight may be seen along highways by 
the light of motor cars. Oviposition also occurs mainly at night or during 
dark days. Eggs are deposited singly on the underside of the leaves of 
peanuts and other host plants. Some are also placed on the upper surface 
and petioles. Rank foliage is preferred for oviposition and there is a tend- 
ency to avoid peanut fields where plants are small and foliage sparse, 
unless the population of insects is very great. 

Development from egg to adult requires approximately 4 to 5 weeks 
during late summer and early fall. The time has been reported as ap- 
proximately 30 to 43 days on velvetbeans in Florida (148), 30 to 36 days 
on soybeans in Louisiana (46) and 32 to 36 days on peanuts in Alabama 
(122). The egg hatches in 3 to 5 days and the caterpillar feeds 16 to 26 
days. Pupation usually occurs in the soil at a depth of one-eighth inch 
to one and one-half inches. Some larvae pupate on the surface of the 
ground under litter and occasionally rolled in a leaf, especially on such 
plants as soybeans and kudzu. The insect remains in the pupa stage 7 to IS 
days during warm weather. 

Little is known regarding the biology of the adult of the velvetbean 
caterpillar. As mentioned previously, many of the moths fly northward 
for many miles and the females then oviposit. The mating habits, pre- 
oviposition period, oviposition period, total egg production, and longevity 
are unknown. Exact information on the distance traveled by moths in 
flight is lacking as is much other pertinent information on the biology of this 
pest. It is known, however, that the moth flies much farther north than 
the insect can overwinter in any stage. All stages perish during the en- 
suing winter. 

Several generations of the velvet-bean caterpillar may occur during a 
season in Alabama, Georgia, Louisiana and northern Florida. Three dis- 
tinct generations were reported in 1929 (46) in Louisiana. Four gen- 
erations were reported in Alabama in 1946 from the middle of June to 
the first of November (122). Larvae of the second and third generations 
cause serious damage to peanuts if the initial infestation occurs early and 
conditions are favorable for the multiplication of the insect. 

Additional research is needed on the biology of the velvetbean 
caterpillar to determine breeding habits, flight, hibernation, host plant 
relationships, relation of temperature to development and survival, and 



INSECT PESTS 215 

factors influencing abundance, such as climatic conditions, diseases, para- 
sites and predators. 

Control — Natural enemies and climatic conditions are of value in re- 
ducing the population of the velvetbean caterpillar but cannot be de- 
pended upon for control. Douglas (46) reported seven species of birds, a 
predaceous wasp, a hymempterous parasite, and a parasitic fungus at- 
tacking the caterpillar. Hinds and Osterberger (73) reported several 
parasites and predators, including a Tachinid, Winthemia rufopicta 
Bigot, which parasitized as high as 70 percent of the caterpillars. They 
also described a parasitic fungus identified (46) as Spicaria prasina 
(Maulk.) Saw, considered synonymous with Botrytis rileyi observed by 
Watson (148). Apparently the same fungus, described by Purswell 
(122), has caused 30 percent fatality to velvetbean caterpillars in fields 
near Dothan, Alabama. Insect enemies of the velvetbean caterpillar 
include Sphex pictipennis (Walsh), Solenopsis geminata (F.), Calosoma 
sayi (Dej.), C. scrutator Fabr., Posidus maculiventris, Proxy s punctu- 
latus, Stir&trus anchor ago (Fab.), Ephialtes aequalis (Prov.), Ophion 
bilineatum Say, and Brachymeria ovata (Say). Dry weather also appears 
to be detrimental to the multiplication of velvetbean caterpillar. 

Insecticidal control of the velvetbean caterpillar on peanuts has been 
found profitable. Early control practices consisted of applying arsenicals, 
such as Paris Green, lead arsenate, and calcium arsenate, but consider- 
able burning of foliage resulted on some crops. Douglas (46) found 
sodium fluosilicate is highly effective and safe on soybeans. Ellisor and 
Floyd (51) found cryolite to be somewhat less toxic to velvetbean 
caterpillar than calcium arsenate and acid lead arsenate, but the degree 
of toxicity indicated the possibilities of cryolite as a control for the insect. 
Guyton (65) reported the effective use of lead arsenate on peanuts 
without injury to foliage. Eddy (48) and Bissell and Alden (16) recom- 
mended cryolite on peanuts. English (52) found cryolite and 3 percent 
DDT dusts highly effective. Moderate gains in yield of peanuts resulted 
from one timely application of these dusts, and where digging was de- 
layed 10 days fewer peanuts were lost in the soil on the dusted plots 
than on untreated areas. The retention of the pods by the dusted plants at 
harvest was especially significant and accounted for most of the benefit 
- derived from dusting. Cryolite, DDT, and benzene hexachloride have 
been reported as highly effective (6). DDT protected peanuts over the 
longest period ; protection given by benzene hexachloride was the short- 
est. Complete protection from caterpillar damage resulted in gains in 
yields of 302 to 573 pounds of dry peanuts per acre on land yielding 946 



216 THE PEANUT— THE UNPREDICTABLE LEGUME 

pounds without dusting. The peanuts were harvested before much loss 
from shedding in the ground had occurred. Loss in the ground was re- 
duced by dusting even after the plants were 90 percent defoliated. 
Unpublished data (7) indicated effective control of velvetbean caterpillar 
with cryolite, 10 percent toxaphene, 2 percent DDT, 1 percent gamma 
BHC, 5 percent methoxychlor, 5 percent DDD, and 1 percent parathion 
each at the rate of 25 pounds per acre. Five percent chlordane was less 
effective. 

Cryolite at the rate of 20 pounds per acre is the standard recom- 
mendation for control of velvetbean caterpillar on peanuts near harvest. 
It is effective and does not injure the foliage. There is no serious residue 
problem. DDT is highly effective at rates as low as 0.36 pound technical 
material (18 pounds 2 percent dust) per acre (161). It is cheaper and 
faster acting than cryolite. Residue studies, however, have shown that 
DDT persists on the peanut foliage which is used as hay. The DDT 
residue on 13 samples of hay collected in Alabama in 1946 varied from 
2 to 31 p.p.m., depending upon the interval between dusting and harvest 
and the rainfall during the period (6). All samples of hay containing less 
than 7 p.p.m. were from fields on which approximately 6 inches of rain 
fell over the 4- to 5-week period between dusting and harvest. In practice, 
peanuts are sometimes harvested within 10 days after dusting. When the 
DDT-treated hay is fed to livestock, the DDT is stored in the fat and 
passed in the milk of the animals. Thus, it is ultimately passed on to 
human beings where it is a possible health hazard, especially to young 
children consuming large quantities of milk. For these reasons cryolite 
is generally recommended in preference to DDT for velvetbean caterpillar 
control on peanuts near harvest. 

In 1949, Wilson and Arant reported ( 160) that four applications of 
2.5 percent DDT applied during the summer months for leafhopper 
control usually control velvetbean caterpillar throughout the season. The 
last application made approximately 30 days before harvest does not create 
a serious residue problem. Where dusting is necessary within 30 days of 
harvest, cryolife or 5 percent methoxychlor is recommended. 

Fall Armyworm J 

Importance. The fall armyworm, Laphygma frugiperda (A. & S.), is 
a periodic pest of peanuts in Alabama, Florida and Georgia. Some 
damage occurs each season in these States, and not infrequently the insect 
is present in sufficient numbers to cause complete defoliation of peanuts. 

Few references to fall armyworm damage to peanuts are found in 



INSECT PESTS 217 

entomological literature. Hinds and Dew (72) reported peanuts as a food 
of this pest, and Robinson (126) reported serious damage in Barbour 
County, Alabama. The pest caused severe damage throughout southeast- 
ern Alabama and southwestern Georgia in 1948 (6, 7). Control 
experiments have shown that fall armyworm may reduce the yield of 
cured peanuts as much as 500 pounds per acre (7, 160). 

In addition to feeding on peanuts, the fall armyworm attacks 
numerous other plants including corn, sorghum, oats and other grasses ; 
alfalfa, soybeans, velvetbeans, cowpeas and other legumes, as well as 
many other types of plants. 

Description of Stages — Detailed descriptions of the life-history stages 
were made by Luginbill (93). Briefer descriptions have been made by 
H. G. Dyar and published by Chittenden (27). The descriptions given 
below of the egg and larva are from Chittenden; those of the pupa and 
adult are from Luginbill. 

Egg 

Eggs [deposited] in a close double layer, one above the other, more or less cov- 
ered with fine gray down from the moth ; spherical, well-rounded, the base a little 
flatter than the apex, uniform ; vertical ribs numerous, about 60, small, joined by 
distinct crossbars nearly as large as the ribs themselves and forming rectangular or 
slightly hexagonal areas ; above, the ribs do not diminish till near the vertex, where 
they become converted into reticulations, smaller toward the micropyle ; color, pearly 
pink; diameter, S mm. 

Larva 

First Instar. Head rounded, bilobed, about as high as wide, clypeus triangular, 
half as high as the head, without perceptible paraclypeal pieces ; labrum quadrate and 
with the mandibles projecting; shining jet black; antennae moderate, pale; setae 
short, pointed ; width .25 mm. Cervical shield straight before, rounded behind, jet black, 
bearing 4 setae on each side; two more (of which one is scarcely visible) detached 
posteriorly, laterally, prespiracular and subventral tubercles single-haired ; anal plate 
semicircular, dusky blackish. Body whitish, slightly translucent, tubercles large, 
round, black with very distinct, short, black, pointed setae. Arrangement normal, no 
subprimaries ; on joints 3 and 4, ia and iia small,- ib and iib large, all well separated 
and equally spaced ; iv and vi single-haired ; on the abdomen i, ii, and iii large, equal, 
i and ii on joint 12 approximately in a square, iv behind the spiracle and with v as 
large as the dorsal ones. Leg shields small, quadrate, black ; ventral tubercles minute, 
also black. Feet of joints 7 and 8 slightly smaller than those of joints 9 and 10. After 
feeding the larva becomes green from the food. 

Second Instar. Head round, slightly bilobed, shining black ; width .4 mm. Body 
as before, a little thicker, and joints 12 more distinctly enlarged; cervical shield 
black ; anal plate not cornified, pale like the body, shaded with gray on the sides. 
Color whitish, with faint traces of dorsal, subdorsal, lateral, and stigmatal lines. 
Tubercles large, black, and distinct as before, the subprimary ones present. Hairs 
short, stiff, black. Thoracic feet black, the others pale, with dark shields. 



218 THE PEANUT— THE UNPREDICTABLE LEGUME 

Third Instar. Head round, shining black, the sides covering the eyes and sutures 
of clypeus, pale luteous ; width .65 mm. Shields and tubercles shining black, tubercles 
large, setae coarse and black. Body greenish gray, dorsal and subdorsal lines whitish, 
straight, narrow, and even ; ground color darker laterally, ending in a blackish shade 
touching tubercle iv, defined on the ventral side. A broad, pale, substigmatal band; 
subventer grayish green, shading to the scarcely paler venter. Body uniform, joint 
12 very slightly enlarged. 

Fourth Instar. Head black, paraclypeal pieces and labrum pale whitish, sides no 
longer pale, but filled in with black mottlings; rounded, slightly bilobed, shining; 
width 1.1 mm. Cervical shield black, bisected, not strongly cornified; anal flap dusky; 
tubercles large, black. Body greenish gray, dorsal, subdorsal (at tubercle ii), and 
traces of narrow lateral lines pale, as before ; substigmatal line broad, white, mottled 
with greenish and divided by a central band of this color. Feet dusky ; setae distinct, 
black, rather long. 

Fijth Instar. Head rounded, slightly bilobed ; clypeus large, the paraclypeal pieces 
nearly attaining the vertex; mandibles prominent; brown-black, sides mottled with 
pale, especially posteriorly, paraclypeal pieces white, as also the verticle suture; 
labrum pale, width 1.8 mm. Body cylindrical, normal, joint 12 very slightly enlarged, 
feet nearly equal. Above dark brown, a little dotted with pale, venter more greenish, 
but also brown mottled. Dorsal line pale, nearly obsolete except on the thorax and 
anal plate; subdorsal line distinct, white, straight, a little broken on joints 12 and 
13 ; stigmatal band broad, sharply edged, not inclosing the spiracles, white, nearly 
filled in with dark red mottlings. Feet all dusky; cervical shield sooty black, not 
strongly cornified, cut by dorsal and subdorsal lines; anal plate dusky, with two 
white spots, formed by the broken dorsal line; tubercles distinct, black, with short, 
stiff, black setae. 

Sixth Instar. Head rounded, bilobed, clypeus large, the paraclypeal pieces reach- 
ing three-fourths of the distance to the vertex; brown-black, sides posteriorly 
mottled with pale, sutures white, all as before; width 3 mm. Body as before, joint 
12 very slightly enlarged, feet equal. Blackish brown above, varying in shade, the 
lateral space tending to be darker, as also a space each side of the dorsal line; 
venter pale greenish, densely mottled. Dorsal line whitish, as broad as the subdorsal 
and regular, but much fainter; subdorsal line mottled with pinkish, straight. The 
pale mottlings of the body are heavier between tubercles i and ii and across tubercle 
iii, suggesting obsolete lines. Slight black streaks bordering the subdorsal line below. 
Substigmatal band broad, sharp, the edges a little irregular, white, filled in with pale 
red mottlings. Feet all dusky; cervical shield black, very narrowly cut by white 
dorsal and subdorsal lines ; anal plate dusky, cut by pale dorsal line, with a con- 
striction anteriorly. Tubercles cornified, distinct, dark brown, largest on joints 12 
and 13 ; tubercle iv on joint 5 is opposite the upper corner of the spiracle, on joints 
6 and 7 below the middle, on 8 at the middle, on 9 above the middle, on 10 at the 
upper corner, on 11 low down halfway between the spiracle and tubercle v, and on 
joint 12 opposite the lower corner of the spiracle. Setae short, rather stiff, dark. 

Pupa 

Dark reddish brown, darker on the prothorax, black immediately before emerg- 
ence of the adult; labrum separated from the clypeus by distinct suture, quadrate; 
fronto-clypeal suture not distinct; libial palpi visible, about one-fourth length of 
maxillae ; mesothoracic wings reaching to caudal end of fourth abdominal segment ; 



INSECT PESTS 219 

metathoracic wings not visible on the venter, maxillae reaching almost to tip of 
wings ; prothoracic legs over half as long as maxillae, their femora exposed ; meso- 
thoracic legs a trifle shorter than maxillae; metathoracic legs showing caudad of 
maxillae not projecting from caudal margins of wings; antennae a little shorter than 
mesothoracic legs ; sculptured eyepiece somewhat broader than the glazed eyepiece ; 
invaginations of the tentorial arms distinct ; vertex narrow on the meson, broader on 
the sides ; mesal length of prothorax one-half that of mesothorax ; mesal length of 
metathorax one-fourth that of mesothorax ; cephalic portion of the fifth, sixth, and 
seventh abdominal segments and the same portion of the fourth abdominal segment 
on the dorsum finely and densely punctured; area around the spiracles slightly 
elevated, blackish ; caudad of each spiracle is a shallow cavity ; spiracles ellipsoidal ; 
mesothoracic spiracle extending over half the length between the antenna and the 
meson, the area blackish; cremaster consisting of two short, stout, blunt spines; 
genital opening of female simple; slitlike, apparently situated on the eighth abdom- 
inal segment, the cephalic margins of the ninth and tenth segments curving strongly 
forward toward the genital opening in this sex; genital opening of male simple, 
slitlike, on the ninth abdominal segment on slight elevation. Length from 14.7 to 
17.4 mm. Greatest width 4.5 mm. 

Male. Head and thorax ochreous suffused with reddish brown ; palpi with black- 
ish patch at side of 2nd joint; frons with blackish bar above; vertex of head suf- 
fused with fuscous ; tegulae with fuscous patches ; pectus whitish ; fore coxae and 
femora suffused with fuscous abdomen ochreous white suffused with reddish brown 
leaving slight pale segmental lines, the anal tuft tinged with rufous. Fore wing 
ochreous whitish suffused with fuscous and reddish brown, the inner area paler; 
subbasal line represented by double oblique dark striae from costa; a black streak 
below base of cell curved up to cell at extremity ; a minute whitish spot defined by 
black on outer side in cell before the antemedial line, which is indistinctly double, 
oblique, waved, somewhat bent outwards in subraedian fold; claviform represented 
by a diffused brownish streak, orbicular whitish defined by black and with pale 
brown centre, a whitish bar beyond it and above base of vein 2 ; reinform with black 
and white bar on inner side, its outer edge slightly defined by black and with irregu- 
lar white marks at upper extremity; a slight white fork at bases of veins of 4, 3; 
an indistinct oblique waved line from lower angle of cell to inner margin; post- 
medial line indistinct, double, strongly bent outwards below costa, then minutely 
waved, incurved at discal fold and below vein 4, some white points beyond it on 
costa ; an oblique diffused whitish shade from apex to vein 6, the whitish subterminal 
line arising from it, excurved at middle and bent outwards to tornus, some short 
black streaks before it in the interspaces at middle; a fine white line before termen 
with series of slight black streaks from it to the black terminal striae ; cilia brown- 
ish with fine white line at base followed by a dark line.^ Hind wing semihyaline 
white, the apex suffused with brown ; a dark terminal line from apex to vein 2 ; the 
underside with the coastal area slightly irrorated with fuscous, a terminal series of 
black striae from apex to vein 2. 

Genitalia. Uncus represented by a stout, sickle-shaped hook or spine; gnathos 
about as long as the uncus ; harpes large and broad, the anal angles not well defined ; 
marginal spines prominent ; claspers hinged at base composed of stout hooks, one on 

5 Var. fulvosa (Male). — Fore wing somewhat more suffused with purplish, the white fascia 
from apex indistinct. 



220 THE PEANUT— THE UNPREDICTABLE LEGUME 

either harpe and attached to it near the anal angle; clavus button- shaped ; juxta 
composed of a chitinized plate in front of aedoeagus attached to articulation of harpes 
by two stout muscles ; ampulla consists of a flap covered with numerous short spines ; 
editum is slender, spiny at tip ; peniculus oar-shaped ; cornutii composed of 3 groups 
of several short spines each. 

Female. Much more fuscous brown, the costal area and veins irrorated with grey, 
the lines less distinct; the orbicular and reniform with slight whitish annuli, the 
former without pale bar beyond it and no white streak at lower angle of cell, the 
whitish fascia from apex obsolete. 

Biology. Adults of the fall armyworm are active during the night and 
in the late afternoon and early morning. The female deposits eggs in 
masses on grasses, peanuts or other suitable host plants. The number of 
eggs per mass is reported ( 146) as varying from 9 to 349, with an aver- 
age of 143 eggs per mass. One female lays an average of about 1,000 eggs. 

The eggs of the fall armyworm hatch in approximately 3 days and the 
young larvae feed at first on the surface of the leaves, skeletalizing them. 
Later they devour the leaves of the plant. The caterpillars feed both in 
the daytime and at night. Occasionally they may be found hiding under 
clods at the base of plants, but this habit is not nearly so pronounced as in 
cutworms. When food becomes scarce, the caterpillars may migrate in 
large numbers seeking additional food plants. Most crops in the path 
of the march may be destroyed by this pest. At maturity the caterpillars 
enter the soil and pupate. 

The life cycle, egg to adult, may be completed in approximately 30 
days. The winter may be passed in the adult stage in the southern part of 
the insect's range. Part of the winter may be passed also in the larval 
stage ( 146) . Apparently, this species is not able to over-winter success- 
fully except in tropical and semi-tropical areas. During the warm months 
the adults migrate northward and may cause damage by fall in central 
and northern States. 

Control. Natural enemies are important in the control of fall army- 
worm. Tachinid flies, hymenopterous parasites, and ground beetles are 
important enemies of the insect. Vickery (146) lists one species of 
Hymenoptera ovipositing in the egg of the fall armyworm and 8 species 
in the larvae. Two species of Diptera and one fungus, Beauveria 
globulifera, are also listed as parasites of larvae. The fiery hunter, 
Calosoma calidum (F.), and other ground beetles are listed as important 
predaceous enemies of fall armyworm (27). The more important 
insect enemies are as follows : Chelonus texanus Cresson, Apanteles 
marginiventris Cresson, Meteorus laphygmae Viereck, Zele melleus 
(Cresson), Sagaritis dubitatus (Cresson), Neopristomerus appalachianus 



INSECT PESTS 221 

Viereck, OphionbilineatuS Say, Euplectrus platyhypenae Howard, 
Frontina archippivora Scudder, Archytas piliventris Van der Wulp. 
Thirteen species of birds and a large number of insects are listed (93) 
as enemies of the fall armyworm. 

Insecticides in the form of dusts, sprays and poison baits have been 
used in control of fall armyworm on various crops. References to 
recommended procedures are too numerous to cite. On peanuts, cryolite 
dust containing approximately 90 percent sodium fluoaluminate has been 
effective when applied at the rate of 20 pounds per acre. Other materials 
which have given effective control in Alabama include DDT, toxaphene 
and parathion (6, 7). A 2.5 percent DDT dust is effective against small 
larvae but may not kill mature caterpillars. A 5 percent material applied at 
the rate of 20 pounds per acre is recommended for full-grown caterpillars. 
Ten percent toxaphene applied at the same rate is also recommended. 
Two percent parathion is effective but, because of its acute toxicity to 
warm-blooded animals, it is not recommended for general use by peanut 
farmers. 

Where a combination insecticidal-fungicidal dust containing 2.5 per- 
cent DDT is applied at intervals during the summer for leafhopper and 
leafspot control, fall armyworm is usually controlled Satisfactorily on 
peanuts ( 160) . If weather conditions and timing of applications are such 
that a population of full-grown caterpillars develops, it may be necessary 
to apply 5 percent DDT at the rate of 20 to 30 pounds per acre in order 
to effect control. Ten percent toxaphene and cryolite appear to be slightly 
more effective against the mature larvae than DDT at concentrations 
of 5 percent and less. DDT and toxaphene are not recommended on 
peanut hay within 4 weeks of harvest. 

Corn Earworm y^ 

Importance. The corn earworm, Heliothis armigera (Hbn.), attacks 
growing peanuts and frequently causes light to moderate damage. Oc- 
casionally, severe outbreaks of the insect occur. The writer has observed 
rather severe damage in 1946 and 1949 over widespread areas in south- 
eastern Alabama. The caterpillars feed on the foliage of peanuts, ragging 
the plants and in some instances defoliating them. This insect not in- 
frequently occurs in mixed populations with velvetbean caterpillar and 
fall armyworm. Heavy losses in yield from defoliation or from severe 
ragging of leaves may occur. Although corn earworm may be considered 
one of the major pests of peanuts during certain seasons in Alabama, 
Florida and Georgia, entomological literature contains almost no references 



222 THE PEANUT— THE UNPREDICTABLE LEGUME 

to earworm infestations in peanuts. Merkl (lOO) lists peanuts as one of 
the principal crops in Alabama being damaged by this insect but based his 
conclusion on unpublished records of the Alabama Agricultural Experi- 
ment Station. So far as the writer is aware, serious damage has not 
been reported in the Virginia-Carolina area. 

Description of Stages. The various stages of the corn earworm have 
been described by several investigators. Descriptions given below are 
taken from the sources indicated. 

The egg has been described by Phillips and Barber (113), Quaintance 
and Brues (124), and others. The description of Quaintance and Brues^ 
follows : 

Egg 

Width, 0.48 mm. ; height, 0.50 mm. Shining, waxy white, faintly tinged with 
yellowish. The form is almost dome-shaped, except that it is slightly narrower at 
the extreme "bottom and widest about the basal third. Base flat and apex obtusely 
rounded. 

The larval and pupal descriptions of Ditman and Cory (45) follow: 

Larva 

First Instar. Length (soon after hatching), 1.5 mm. Head and thoracic legs, shiny 
black. Body newly hatched larva very pale and rather transparent ; after some feed- 
ing, opaque and creamy yellow. There is a very slight tendency to darker and lighter 
longitudinal stripes, at least in larvae nearly ready to molt the first time. Setae of 
body of rather medium length, black ; on head, some are black and others of a lighter 
color. Cervical shield and minute setigeral warts dull brownish black; also the 
prolegs externally, and the anal plate. Around each setigeral wart is a poorly de- 
fined circular space of whitish beyond which the generally yellow color of the body 
appears. The characteristic minute dermal spinules of the older larva are scattered 
and very indistinct in this instar. 

Second Instar. Length, 3.4 mm. Appearance much the same as in first instar. 
Differs in that the setigeral warts are much broader and show up clearly to the 
naked eye. The dermal spinulation is more pronounced and general. The longitudinal 
stripes are but little more evident, if any, than in the previous stage. In the first 
two or three instars the larvae have a semi-looping gait as do the younger larvae of 
some of the cutworms. 

Third Instar. Length, 7.0 mm. Head, olive brown with darker brown mottlings, 
especially on each side near vertex ; bears a few fine setae. Cervical shield black or 
slightly brownish, with two short white lateral stripes. Body entirely covered with 
minute blackish spinules, appearing like a "sand-paper" surface as compared with the 
skin of most of the related caterpillars. Four narrow white dorsal stripes and a broad 
white band laterally, alternated' with olive brown. Setigeral warts prominent, shiny 
black, and obtusely cone shaped rather than nearly flat as in previous instars. Setae 
moderately long and shiny black. Dorsal abdominal warts are larger, especially on 
first and second segments. Thoracic legs black; prolegs black on their sides both 
experiorly and on the mesal surface. Crochets black. 



INSECT PESTS 223 

Fourth Instar. Length, 11.4 mm. Appearance much as in third instar. Differs in 
the fact that some of the dorsal stripes laterally now appear broken into short, ir- 
regularly disposed lengths interrupted by dark ground color. There is a broader 
lateral white band in or near which the spiracles lie. 

Fijth Instar. Length, 17.9 mrti. In general, this stage marks the change to greater 
contrasts in the markings and to more brilliant colors. The appearance of red hues, 
as on the ventral surface and in the paler portions of the body markings, is now 
quite general. Head, orange brown with fine pale setae. Cervical shield and setigeral 
warts as before, but the latter bearing pale setae. The shield may lose its dark color 
in many specimens, however. All legs pale; claws of thoracic legs and crochets of 
prolegs are brownish. Two continuous mid-dorsal white lines now enclose a darker 
area appearing as a blackish band, in the middle of which lies a third white line. 
Dorsum laterally to white spiracular band transversed by short white lines on a red 
and gray ground which becomes darker near the lower edges and tends to concentrate 
in segmental dark patches in some specimens. 

Sixth Instar. Length, 24.8 mm. Appearance much as in the fifth instar, but in 
general more brightly colored and showing more pronounced individual variation in 
the nature of the markings. Cervical shield not so dark, and less distinct from the 
surroundings in many cases, although in some types of larvae it is very distinct. 

Pupa 

The pupa, just after it is rid of the larval skin, is very soft and delicate and 
almost larviform. It is pale green on the head and thorax ; the wings are transparent 
with the venation showing as whitish lines ; the abdomen is whitish and opaque, with 
shades of rosy pink dorsally, and orange-colored spiracles. A large transverse rosy 
spiracle anteriorly bordered with white lies on each side of the prothorax ; a trans- 
verse median rosy spot between the eye ; and four black dots on each eye. 

In a half hour after the molt, the pupa has begun to contract and press its ap- 
pendages into 'the places habitually taken by them and the pupa. The colors are 
hidden by the darkening and hardening of the chitinous coat of the pupa. This change 
to the natural shiny brown of the pupa takes place rather slowly over a period of 
a day or more. The first portions of the body to darken are the head and dorsal 
regions of the thorax and abdomen. 

Measurements of twenty-two pupae showed that there is comparatively little 
variation in size in this stage. The length was found to average 19.1 mm., ranging 
from 17.6 mm. to 20.6 mm. The breadth of the pupa at the widest point across the 
back or dorsum is a little greater than the greatest depth from the dorsal to the 
ventral surface. The average measurement in the first cases was S.S mm., while the 
average depth was 5.4 mm. 

The original description of the adult (53) was translated by Ditman 
and Cory (45) as follows: 

Adult 

A bombyx, with wings deflexed and yellowish; with a middle spot 'and posterior 

obsolete streak rather obscure. Habitat, islands of ScSiith America. Collector, Father 

Smith. Of medium size. The antenna simple. The' body yellowish with a more obscure 

middle spot. Posteriorly with an obsolete streak which is spotted with very small 



224 THE PEANUT— THE UNPREDICTABLE LEGUME 

punctures. Hind margins brownish. Hindwings yellowish, with posterior margin 
fuscous. 

Biology. Studies on biology of the corn earworm have been made by 
numerous workers (81, 112, 13, 45). The insect over-winters in the pupal 
stage which may be found 2 to 6 inches below the surface of the soil. The 
adult emerges in the spring or early summer, and the females soon 
begin depositing eggs. Eggs are laid singly on the leaves and terminal 
buds of many plants. When corn in the silking stage is present the eggs 
are deposited on the silks. One female may lay as many as 3,000 eggs. 
On peanuts, the caterpillars feed on the leaves, causing ragging of the 
foliage, or even complete defoliation of the plants. When the larva is ma- 
ture it pupates in the soil. Time required for complete development, egg to 
adult, is approximately 30 days under favorable conditions. 

In addition to feeding on peanuts, this insect is a major pest of several 
other crops including sweet corn, field corn, cotton, tomatoes, tobacco, 
soybeans and other plants. It is commonly called corn earworm, tomato 
fruitworm, or bollworm, depending upon the crop it infests. 

The moths are most active at dusk or during warm, cloudy days. They 
are strong flyers and may migrate for considerable distances before de- 
positing eggs. There appears to be a tendency for the migration to be 
northward. 

Control. The literature available on control of corn earworm is too 
extensive to review in this paper. Winburn and Painter ( 162) reported 
46 hymenopterous and 22 dipterous insects that aid in natural control. An 
enormous amount of research has been conducted on the chemical and 
cultural control of Heliothis armigera on corn, cotton, tomatoes and 
several other crops. However, very little information is available on con- 
trol of this insect on peanuts. Experiments conducted at the Wiregrass 
Substation of the Alabama Agricultural Experiment Station have shown 
that the insect may be successfully controlled on peanuts with cryolite, 
DDT or toxaphene (5, 7, 8). The insect is most readily controlled when 
the larvae are small. Full-grown caterpillars are somewhat resistant to 
most insecticides. Cryolite should be used undiluted at the rate of at least 
20 pounds per acre for control of earworms on peanuts. Two and one- 
half percent DDT dust at the same rate is effective against small larvae. It 
is not highly effective against mature forms. Where a population of fully 
grown caterpillars develops before control measures are applied, a dust 
containing at least 5 percent DDT is required for satisfactory results. Ten 
percent toxaphene is highly effective against small larvae and moderately 
so against mature forms. 



INSECT PESTS 



225 



The recommended practice for control of corn earworm in the Ala- 
bama-Florida-Georgia area is applications of 2.5 percent DDT at 7- to 
10-day intervals in a regular dusting program for control of insects and 
diseases ( 160) . Where infestations of last-instar larvae are found 5 per- 
cent DDT, 10 percent toxaphene, or cryolite should be used. Infestations 
which occur within 4 weeks of harvest should be c9ntrolled with cryolite 
if the vines are to be used for hay. 

Potato Leafhopper 

Importance. The potato leafhopper, Empoasca fabae (Harr.) may 
attack peanuts wherever they are grown commercially in the United 
States. The related species Empoasca facialis Jac. is reported on peanuts 
in South Africa (107) ; E. solana DeLong occurs on peanuts in Hawaii 
(76) and E. flavescens (F.) on peanuts in Dutch East Indies (89)., 

In addition to injuring peanuts, E. fabae attacks a wide variety of 
plants including potato, bean, clover, alfalfa, soybean, eggplant, rhubarb, 
cotton, dahlia, apple and many other plants. Several common names 
have been used for this insect, each referring to a host plant. It might be 




Figure 2. Leafhopper damage to peanut leaflets. (Upper leaflet normal; two lower 
leaflets damaged.) 



226 THE PEANUT— THE UNPREDICTABLE LEGUME 

called peanut leafhopper, but the official common name is potato leaf- 
hopper, a name suggested by Ball (12) to indicate potato as a preferred 
host. 

Both adults and nymphs of the insect feed upon peanuts by sucking 
juices principally from the lower epidermis and veins of the leaves. Some 
damage may result also from the deposition of eggs. As a result of leaf- 
hopper damage to peanuts, the tips of the leaflets turn yellow and as the 
damage becomes more acute the yellowing progresses toward the base 
of the leaflets and some of the tips may appear burned. Damage is more 
severe during dry weather. A field of infested peanuts may have a yellow- 
ish appearance rather than characteristic green. Batten and Poos (14) 
reported a dwarfing as well as yellowing of foliage in severe infestations 
in Virginia. Metcalf ( 102) reported a disease called "pouts" resulting in 
peanuts from the mass effect of toxins injected by E. fabae; the leaflets 
turned dark at the tips, and the whole leaf sometimes blackened and 
died. Apparently, this condition was severe "hopperburn" ; it should not 
be confused with a dwarfed condition, also sometimes called "pouts," re- 
sulting from thrips damage. 

There is considerable evidence that leafhoppers reduce the yield of 
peanuts (117, 14, 104, 7). In some instances, however, there has been 
no clear differentiation between the effect of damage from leafhopper 
and Cercosporo leafspot. There is need for more exact information on 
losses caused by potato leafhopper to Spanish, runner and jumbo types of 
peanuts. The losses should be measured in terms of yield of peanuts and 
yield and quality of hay. 

Description of Stages. The potato leafhopper was originally described 
by Harris in 1841 (66) as Tettigonia fabae and the Genus Empoasca was 
established by Walsh in 1864. Subsequently, numerous descriptions have 
been published under several synonymous names. The descriptions of im- 
mature stages given below are from Ackerman and Isely ( 1 ) ; that of the 
adult is from DeLong (42) : 

Egg 

Egg elongate, subcylindrical, very delicate, slightly curved from end to end, some- 
what rounded at both ends, but more so at the anterior end. When first deposited it 
is rather transparent, but in a few days it changes to a pale yellow while a small 
white cap forms at the anterior end through which the red eyes of the immature 
nymph are perceptible. Average length 0.82 mm., width 0.25 mm. 

Nymph 

First instar. Pale white, changing to a light yellowish green after feeding. Eyes 
dull red. Small pale spines on the dorsal side of the head, thorax, and abdomen ; the 
latter with four spines to each segment arranged in two longitudinal rows along 



INSECT PESTS 227 

each side, one spine situated dorso-laterally, the other ventrolaterally. Posterior 
margin of metathorax blunt. First two segments of antennae pale, the remainder 
dusky. Average length 1 mm. 

Second instar. General color light yellowish green. Eyes losing some of their 
red color. Posterior border of metathorax sharp in outline. First two segments of 
antennae light yellow, remainder dusky. Average length 1.30 mm. 

Third instar. General color pale yellowish green. Eyes almost pearl white. Body 
more robust than in first two stages. Wing pads appearing as lateral buds extend- 
ing to the hind margin of the first abdominal segment. Spines darker and more 
prominent. Average length 1.85 mm. 

Fourth instar. Head and thorax yellowish green; abdomen yellow. Eyes pearl 
white. Wing pads extending to hind margin of second abdominal segment. Spines 
prominent. Average length 2.1 mm. 

Fifth instar. Head and thorax pale green ; abdomen yellow. Wing pads extending 
to, or nearly to, the hind margin of the fourth abdominal segment. First two antennal 
segments green, remainder dusky. Body broader than in previous instar. Average 
length 2.6 mm. 

Adult 

Pale green, usually with a row of white spots on anterior margin of pronotum. 
Length 3.S mm. 

Vertex bluntly angled, a little longer on middle than next to eye and about one- 
third wider between eyes than length at middle. 

Color. Yellowish to pale green, markings variable; vertex frequently with 
pale or dark-green spots ; pronotum usually with a row of six or more pale spots 
along anterior margin, sometimes missing or indistinct ; elytra greenish subhyaline. 

Female genitalia. Last ventral segment moderately produced and roundedly 
truncated. 

Male genitalia. Valve produced and roynded or bluntly angled ; plates triangularly 
tapered to pointed apices, which are frequently upturned; lateral processes of the 
pygofers rounded on inner margins and broadened on apical half, then concavely 
rounded to narrow attenuated tips, which are slightly curved inward; spines of 
tenth segment broad, with tips narrowed and directed downward. This combination 
of characters will distinguish Empoasca fabae from closely related species. 

Biology. Many studies have been made on the biology of potato leaf- 
hopper on potatoes, beans and other crops, but none has been made on 
peanuts except in the form of general observations. Beyer (IS) reported 
the results of life-history studies of the insect on beans in Florida and 
Poos (114) reported similar studies on cowpeas in Virginia. There like- 
wise are rather comprehensive reports from other sections on the biology 
of the insect (54, 1,41). 

The potato leafhopper apparently over-winters only in the Gulf-Coast 
States where some breeding may occur throughout most of the winter. As 
the weather becomes warm in the early summer it spreads northward and 
causes damage to a variety of crops during the summer and fall. Cold 
weather presumably destroys all stages of the insect except in its south- 



228 THE PEANUT— THE UNPREDICTABLE LEGUME 

ern range, where the winter may be passed on any green host plant such 
as alfalfa, clovers, castor beans and other plants. Beyer (15) found it 
throughout the winter on castor beans. It is possible that hibernation may 
occur, either in the egg or adult stage, in part of the insect's range, but 
all evidence on hibernation is negative. 

The time required for development from egg to adult is 18 to 24 days 
during warm weather (42, 14). As the weather becomes cool, this period 
may increase to 60 days. Approximately S to 10 days are required for 
incubation of eggs and 8 to 15 for nymphal development. Females mate 
and begin ovipositing in 3 to 5 days in the veins and petioles of the leaves. 
Approximately 60 eggs per female are deposited over a period of 30 
days during warm weather. A maximum oviposition of 131 fertile eggs 
has been reported in Florida (15). 

The average longevity of the female is approximately 35 days, al- 
though a maximum of 123 days has been reported in Virginia (114). 
Longevity of males is somewhat shorter. Six generations per year have 
been reported in Virginia and Florida. 

Additional research is needed on potato leafhopper to determine its 
development on peanuts, overwintering habits, and the relation of de- 
velopment on various wild and cultivated host plants to damage in 
peanuts. 

Control. Natural enemies are apparently of relatively minor value in 
suppressing the population of potato leafhopper. Heavy rainfall reduces 
infestation in peanuts. A parasitic fungus, Entomophthora sphaerosperma 
Fresenius, causes a disease which is of considerable importance. The 
disease has been reported from Florida (15), Arkansas (1), Iowa (54), 
and other localities. Eighty percent of the insects may be diseased, and as 
high as 37 percent of those affected may perish. Chrysopid and coccinellid 
larvae are important insect predators of the potato leafhopper, Chrysopa 
plorebunda Fitch and Hippodamia 13-punctata being species commonly 
observed. The predaceous bug, Triphleps insidiosus Say is also a natural 
enemy as are certain spiders, ants and birds. Insect parasites in potato 
leafhopper appear to be rare, although Anagrus armatus Ashm. is re- 
ported common in Iowa. 

Numerous studies have been made on insecticidal control of potato 
leafhopper on potatoes, beans and other crops. Some studies have been 
made also on peanuts. Poos and Batten (117) found that 4:4:50 Bor- 
deaux mixture applied to peanuts in Virginia increased the yield 21 per- 
cent. In 1938 these investigators reported more extensive experiments 
with sulfur and copper dusts and sprays which resulted in very substantial 



INSECT PESTS 229 

increases in yield. Miller (104) reported similar results. In none of these 
reports was there a clear differentiation between increases from leafhopper 
and disease control, although leafspot is given as a factor. The same 
authority ( 106) has reported the potato leafhopper as the most injurious 
insect of peanuts in Virginia, and stated that sulfur applied for leaf-spot 
control repelled and controlled leafhopper, even on undusted areas in 
small-plot experiments. Poos (116) found that 2 percent DDT reduced 
the infestation of the insect on peanuts and Poos, Grayson, and Batten 
(120) reported some increase in yield of peanuts and hay from control 
of leafhopper, but none of the differences was significant. Non-significant 
increases were also recorded (5) in yield of sound, shelled peanuts in 
Alabama in 1947 from the use of DDT sprays and dusts on runners. In 
1948b, however, the dusting of Spanish peanuts 4 times for leafhopper 
control in Alabama resulted in decreased infestation and in average gains 
in yield as follows: 2 percent DDT, 302 pounds dry peanuts per acre 
gain; 2 percent DDT in 90-10 sulfur-copper, 468 pounds per acre; 20 
percent toxaphene, 470 pounds (7). Two percent gamma BHC and 5 
percent chlordane were less effective. Four applications of dust to runner 
peanuts for leafspot and leafhopper control resulted in average gains in 
yield as follows: Sulfur-copper, 90-10, 264 pounds of dry peanuts per 
acre; 2 percent DDT, 339 pounds per acre; sulfur-copper plus 2 percent 
DDT, 444 pounds. Where 10 dustings were made with DDT throughout 
the season, no significant gains were recorded. In a non-replicated, pre- 
liminary test, 9 dustings with 20 percent toxaphene for thrips and leaf- 
hopper control resulted in excellent control of both insects and a 67 per- 
cent increase in yield over the check. 

Thus it appears that control of potato leafhopper on peanuts is profit- 
able. It also appears feasible to control leafspot and leafhopper in one 
operation with a combination insecticide-fungicide. Little is known, how- 
ever, regarding the relative value of controlling the insect on Spanish, 
runner and Jumbo peanuts. Little is known regarding the value of con- 
trol on different soils, although observations indicate that damage is more 
severe on poor than on more fertile soils ; presumably more profits might 
be derived from control on the less fertile soils. 

A combination insecticidal-fungicidal dust has been recommended 
( 160) for control of leafhopper and leafspot in one operation. The dust 
rtiixture recommended contains 2.5 percent DDT, 3.4 percent copper, and 
at least 65 percent sulfur. Four to 5 applications of the dust are applied 
at approximately 10-day intervals. The last dusting should be 4 weeks 
before harvest, if the peanut vines are to be used as hay. The DDT-sulfur- 



230 



THE PEANUT— THE UNPREDICTABLE LEGUME 



copper dust is recommended for peanuts in the Alabama-Florida-Georgia 
area. 

A dust containing 1 percent DDT and 90 percent sulfur has been 
recommended (119) for dusting peanuts in the Virginia-Carolina area. 
Three applications are recommended at 3-week intervals, beginning July 
10 to 15. 

Tobacco Thrips ^ 

Importance. Thrips damage to young peanuts is widespread over most 
of the peanut-producing areas. The tobacco thrips, Frankliniella fusca 
(Hinds), is the principal species involved, although the flower thrips, 
F. tritici (Fitch), also infests peanuts, living mainly in the flowers ( 120) . 
Heliothrips indicus occurs on peanuts in Sudan (32). Taeniothrips dis- 
talis Ky. and T. longistylus Ky. are reported damaging peanuts in India 
(125). 

Apparently, the first thrips injury to peanuts in the United States 
was observed by Watson ( 149) when he collected F. fusca from this crop. 
In 1922 he reported widespread damage in Florida during the spring of 
1919. Since that time the insect has been observed throughout most of the 
peanut-growing section of the country. In addition to peanuts, F. fusca 







Figure 3. Leaflets of peanuts showing typical thrips damage. 



INSECT PESTS 231 

attack tobacco, cotton, beans, peas, Irish potato, oats, cocklebur, dew- 
berry, evening primrose, crab grass, tomato, vetch and many other plants 
(77,49). 

Thrips attack peanut plants ~most severely while they are small. The 
upper surface of the developing leaflets are rasped by the insects and as 
the leaflets unfold they have a scarred and even deformed appearance. 
Farmers often refer to damaged peanuts as "possum-eared," a term quite 
suggestive of the appearance of the leaflets. The plants fail to grow prop- 
erly. Where infestations are severe, stunting occurs and the damaged 
peanuts recover slowly and perhaps incompletely. Thrips damage usually 
disappears or becomes less acute, concurrently with increased rate of 
growth of the plants, the more rapid growth probably resulting from 
the nitrogen fixation and favorable climatic conditions. 

Thrips injury has been referred to as "pouts." The peanuts, in farmer 
language, were said to pout until blooming time when growth became 
more rapid (115). Another condition caused by potato leaf hopper has 
also been called "pouts." It is apparent that the term "pouts" is not 
specific, and should not be used to designate thrips injury ( 133) . 

It has been assumed by many that peanuts grow out of the stunted 
condition resulting from thrips infestation and little permanent harm re- 
sults. Recent studies discount this view. As a result of experiments at 
Beltsville, Maryland, it was concluded (116) that thrips reduced the yield 
of peanuts as much as 2)7 percent. Substantial increases in yields were 
reported, in some instances, from control of thrips in Maryland and 
Virginia (120). The author (7) found that control of thrips on runner 
peanuts resulted in the setting of fruit earlier than on undusted plants, 
although most of the early crop was lost in the ground at harvest. It ap- 
pears that permanent damage may result from thrips infestation resulting 
in decreased yield of peanuts. 

The degree of damage doubtless varies with the type of peanuts, fer- 
tility of the soil, and weather conditions as well as with the insect infesta- 
tion. Apparently, damage is more severe and recovery slower on poor 
than on fertile soils. Additional research is needed to clarify these points. 

Description of stages. Two forms of F. fusca adults occur (49), one 
with shorter wings than the other. The relative length of wings varies also 
with the distention of the abdomen at the time of measuring. It is not 
clear from the literature whether the original description of the insect 
(69) was of the short- or long-winged type. In 1905, however, the insect 
was described (70) under the name Euthrips nicotiannae from long- 
winged females, These descriptions are given belpw ; 



232 THE PEANUT— THE UNPREDICTABLE LEGUME 

Egg 

The eggs are deposited in the tissues of the stem and leaves. 

Larva, first stage 

Length about 0.23 mm.; width of mesothorax 0.11 mm. General shape fusiform. 
Color of posterior part of thorax and entire abdomen pale yellow ; elsewhere pearly 
white. Head quadrate; eyes reddish. Antennae 0.15 mm. in length; distinctly four- 
segmented; basal segment cylindrical, short; second ovate, slightly shorter than 
the third; third slightly conical, the apex joining the second; fourth fusiform, 
widest near the basal fourth, about equal in length to the other three. The fourth seg- 
ment is distinctly annulated, the second and third indistinctly so; setae are present 
on all segments, most numerous on the fourth. Legs translucent white, stout. Abdo- 
men tapering posteriorly; with ten segments, the first eight nearly equal in length, 
the ninth twice and tenth three times the length of the preceding. Each abdominal 
segment with longitudinal rows of setae, the ninth with two and tenth with four 
spines that are four times the length of the setae. 

Larva, second stage 

Length from 0.6 to 1.17 mm. ; width of mesothorax from 0.14 to 0.2 mm. ; shape 
same as in first stage. Color of thorax and abdomen yellowish, with exception of the 
last abdominal segment. Head quadrate; antennae with four segments, the fourth 
being more distinctly annulated than in the first stage. Abdomen with the setae in- 
creasing in length posteriorly; ninth and tenth segments about equal in length, 
each less than twice the length of the others. 

The young nymph or prepupa 

Length, 0.52 to 0.62 mm.; width of mesothorax, 0.10 to 0.12 mm. Antennae 
translucent, extending forward, much shortened and composed of five segments, 
first two cylindrical and very short, third and fourth globose, fifth tapering to the 
apex. The last segment of the abdomen is set with four spines by use of which the 
young nymph seems to protect itself, when approached by another the abdomen 
being turned upon it. The wing sheaths are very noticeably separated, the upper one 
extending to the middle of the second segment, the lower one to the middle of the 
third segment. The legs are translucent white, stout. 

The full-gromn nymph or pupa 

Length, 0.68 to 1.22 mm.; width of mesothorax, 0.15 to 0.20 mm. Shape similar 
to the adult. Color yellowish; head, antennae, wing pads, legs, and caudal segments 
of the abdomen varying to pearly white. Antennae extending to the middle of the 
prothorax. Three yellowish ocelli between the eyes, the latter dark red. Wing pads 
so closely applied as to appear single, extending to the middle of the fifth abdominal 
segment ; length from head to tip of wing pads 0.39 mm. The abdomen is noticeably 
contracted longitudinally; greatest width, 0.24 mm.; longest setae, 0.078 mm. 

Adult 

Average length, 1.05 mm. (0.95 to 1.13 mm.) ; average breadth at middle of 
abdomen, 0.27 mm. (0.225 to 0.285 mm.). General color of head and thorax light 
brown or tawny yellowish-brown ; abdomen dark brown. 

Head about one and one-half times as wide as long, frequently slightly retracted 
under anterior margin of prothorax ; occiput transversely wrinkled, posterior margin 
strongly thickened and darker in color; anterior margin slightly bisinuate, cheeks 



INSECT PESTS 233 

approximately straight and parallel. Eyes dark red in color, not protruding, occupy- 
ing together fully one-half the width of the front of the head and being one half as 
long as the head; margins around eyes pale yellow in color; surface of eyes finely 
faceted and slightly pilose; three ocelli present, well separated, posterior ones con- 
tiguous with yellow borders to eyes, pale yellow in color and margined inwardly 
with pale-orange crescents; one moderately stout dark spine in front of each 
posterior ocellus ; postocular spines weak and inconspicuous. Mouth cone reaching 
nearly to posterior edge of the prosternum, tapering abruptly; maxillary palpi 
slender, three-segmented. Antennae inserted slightly below front margin, approxi- 
mate at base, about two and one-half times as long as the head and approximately 
equal to breadth of mesothorax. 

Segment 1 is rounded, three-fourths as long as broad ; 2 is broad as/1 ; following 
segments about three-fourths as thick ; segments 3 to 6 are constricted at bases, be- 
coming more stout successively. Color of segments 1 and 2 uniform light brown ; 3 
to S pale yellow at bases, shading to brown at outer ends, each succeeding segment 
from 3 to 6 becoming darker in color ; 6 to 8 are dark brown. Spines upon segments 
2 to S are of medium size, but not very conspicuous. Color of head varying from 
gray-brown to yellow-brown. 

Prothorax about five-ninths as long as broad and slightly longer than the head ; 
sides rounded, slightly wider at hind than at fore angles ; one stout spine at each 
anterior, and two stouter spines of equal size at each posterior angle; anterior 
marginal pair of spines about one-half as long as those at front angles; usual row 
of five spines on each side of hind margin, of which number 4 is equal in strength 
to those on the front margin. Mesothorax nearly one and one-third times as wide as 
the prothorax, broadest posteriorly, sides curving outward; mesonotum without 
conspicuous spines, posterior margin forming an obtuse angle in middle. Metathorax 
slightly narrower than mesothorax, sides nearly parallel, broader than prothorax 
at posterior edge; metanotum bears two pairs of spines at front edge, the inner 
pair as strong as those at front angles of prothorax. Wings present (probably 
reduced at some season of year), average length about 0.68 mm., not reaching to the 
tip of the abdomen, breadth equal to about one-thirteenth of their length ; fore 
wing has two longitudinal veins, each bearing stout spines set at regular intervals; 
fore wings shaded ash gray, hind wings gray only along basal three-fourths of 
midvein; spines on wing veins dark brown and conspicuous; costa bears 19 to 24 
spines ; fore vein, 13 to 18 ; hind vein, 10 to 12 ; scale, 5 ; interior of scale, 1 ; fringe of 
hairs on costa of fore wing quite heavy, in length exceeding the breadth of the 
wing. Legs of medium length, lighter than body in color, pale yellow, shaded more 
or less with brown on upper side of middle of femora and tibiae; a pair of stout 
brown spines at inside of tip of each tibia, small brown spines scattered along femora 
and tibiae ; spines standing in two rows on inner side of hind tibiae are weak and 
only about four in each row. 

Abdomen nearly cylindrical to eighth segment, then tapering abruptly to an 
acute tip ; color uniformly dark brown ; a still darker-colored narrow chitinous 
thickening extends across dorsal side of segments 2 to 8 near anterior edge. Three 
or four quite stout and rather conspicuous dark-brown spines stand at each side of 
dorsal plates on 2 to 8; six rather prominent spines stand in a row on posterior 
edge of ventral plates 2 to 7 ; terminal spines stout and prominent ; tenth segment 
split open along dorsal median line. 



234 THE PEANUT— THE UNPREDICTABLE LEGUME 

Biology. Development of the tobacco thrips is gradual, but approaches 
a complete change (55). Eggs deposited in tissues of the foliage hatch in 
about 7 days in South Carolina (156). The immature form passes 
through two larval stages, during which feeding occurs, the two stages 
requiring 5 to 6 days. According to Hooker {77), the mature larva 
"crawls to some obscure nook," becomes inactive and pupates.® This stage 
is quiescent and does not feed. At the end of 3 to 4 days the adult emerges 
and shortly begins feeding. The time for development from egg to adult is 
approximately 16 days, the period being shorter in warm weather and 
longer when the temperatures are relatively low. 

Breeding of the tobacco thrips is continuous throughout the warmer 
months. Five overlapping generations have been reported (49) in South 
Carolina from April 10 to October 18. The female lives for an average of 
approximately 30 days and deposits 50 to 60 eggs (156). Nonfertile eggs 
produce males and fertile eggs apparently produce only females (135, 49, 
157). Males live for a shorter period than females and are usually less 
numerous in the field. 

The tobacco thrips presumably hibernate under grass or in other 
protected places. It is possible that intermittent breeding takes place on 
wild and cultivated host plants during the warmer periods of the winter 
in the southern range of the insect, but specific evidence on this point is 
lacking. So far as is known, only the adult females over-winter (49) . 

Volunteer peanuts are a factor in breeding destructive population of 
thrips in Alabama, Florida and Georgia. Many peanuts lost at harvest 
remain in the ground over winter and germinate the following spring. 
Usually these volunteer plants emerge a few weeks earlier than the regu- 
lar crop. The thrips multiply on the volunteers and then migrate to the 
younger plants, where peanuts follow peanuts in rotation. Doubtless other 
early host plants are also of importance in this respect. 

Much additional information is needed on the biology of the tobacco 
thrips with emphasis on overwintering habits, succession of host plants 
in relation to injury to peanuts, and development of the insect on peanuts. 

Control. Heavy rainfall is one of the most effective natural controls 
of tobacco thrips. This fact was noted as early as 1907 {77). Predaceous 
insects are also of value in reducing the population. A true bug, 
Triphleps'^ insidiosus Say, was reported as feeding upon F. jusca {77). 
The ladybird, Hippodamia convergens Guerin, and a lacewing, Chrysops 

^ The closely related species F. tritici usually pupates in the ground (157). It is possible 
pupation of F. fusca may occur in the soil as well as on the host plant. 
' Onus. 



INSECT PESTS 235 

sp. have been reported as predators of F. tritici (157) and these forms 
probably prey on F. jusca also. 

Chemical control of tobacco thrips is feasible. The first treatments 
consisted of nicotine-soap sprays {77, 49) and rotenone (86). Following 
the use of tartar emetic ( 108) against onion thrips, Thrips tahaci Lind., 
the material was used on peanuts and other plants in the greenhouse with- 
out injury to the crops (3) . Tartar emetic sprays were used on peanuts in 
the field, but the applications were too late for successful control (115). 
Poos (116) reported successful control with DDT in the form of 2 per- 
cent dust, 0.66 percent sprays, and 10 percent aerosols and with tartar 
emetic sprays. Satisfactory control of tobacco thrips on peanuts with 
significant increase in yield from the use of DDT and BHC dust and 
sprays has been reported ( 120) . The most efifective treatment consisted of 
three applications of an emulsion containing 4 percent DDT applied by 
atomizing at the rate of 10 gallons per acre. The author (5) found 3 per- 
cent DDT dust more efifective than 20 percent Sabadilla, 1 percent 
rotenone, or 1 percent nicotine. A spray containing 1.5 percent water- 
dispersable DDT was much more efifective against the thrips than 3 per- 
cent dust. In 1948, he reported 2 percent Gamma BHC and 20 pdtcent 
toxaphene applied as dusts at the rate of 20 pounds per acre gave much 
better control than 2 percent DDT dust. 

Data on gains in yield of peanuts resulting from control of tobacco 
thrips are somewhat contradictory. One study (120) reported increases 
as high as 36 percent in the weight of green pods in some experiments 
and no increases in others. A second study (7) reported an increase in 
the weight of peanut pods set early on DDT and BHC plots but, as men- 
tioned previously, most of the early crop was lost in the ground at harvest. 
In a nonreplicated preliminary test 20 percent toxaphene dust applied for 
thrips and leaf hopper control resulted in 810 pounds dry peanuts® per 
acre more than was harvested from undusted peanuts. It appears that 
gains in yield from control depend upon the severity of the thrips infesta- 
tion, the efficiency of the control, the type of peanut concerned, fertility of 
the soil, weather conditions, and other factors. Additional research is 
needed on these points. 

White-Fringed Beetle 

Importance. The white-fringed beetle, Pantomorus leucoloma (Boh.)^ 
is potentially the worst pest of peanuts in southeastern United States, 

s Seven percent moisture content. . ,t. i. n ^t j: • , j- „ . 

' Also known as Graphognathus leucoloma fectmdus (Buch.) ; other forms including Pantomorus 
(.Graphognatkus) peregrinus Buch., G. leucoloma striaius (Buch.),G. leucolqma dubius (Buqh.J 
are also of economic impprtanc?i 



236 THE PEANUT— THE UNPREDICTABLE LEGUME 

although at present its limited distribution prevents widespread losses to 
the crop. This pest's first appearance in the United States was in 1936 
when it was found causing damage to cotton and peanuts in northern 
Florida (154, 155). Shortly thereafter it was discovered in southern 
Alabama. In spite of rigid quarantines and intensive control work which 
has restricted the dispersal of the pest, it is established^" in 115 counties 
in seven Southern States. The infested area in some counties is very 
small. The distribution of the white-fringed beetle, by States and counties, 
is given by G. G. Rohwer of the U. S. Bureau of Entomology and Plant 
Quarantine as follows: 

Alabama : Baldwin, Chilton, Coffee, Conecuh, Covington, Crenshaw, Dallas, 
Escambia, Geneva, Jefferson, Lowndes, Mobile, Monroe, Montgomery, Wilcox. 

Florida : Escambia, Holmes, Oklaloosa, Santa Rosa, Walton. 

Georgia : Baldwin, Ben Hill, Bibb, Bleckley, Bulloch, Burke, Candler, Clarke, Clay- 
ton, Clay, Cobb, Coffee, Coweta, Crawford, Crisp, DeKalb, Dodge, Dooly, 
Emanuel, Evans, Fulton, Habersham, Harris, Houston, Irwin, Jasper, Jefferson, 
Johnson, Laurens, Macon, Monroe, Montgomery, Muscogee, Newton, Peach, 
Putnam, Richmond, Screven, Spalding, Sumter, Talbot, Tattnall, Taylor, Telfair, 
Toombs, Treutlen, Troup, Turner, Twiggs, Washington, Wheeler, Wilcox, 
Wilkinson. 

Louisiana : Iberia, Jefferson, Orleans, Plaquemines, St. Bernard, St. Tammany, 
Tangipahoa. 

Mississippi : Attala, Covington, Forrest, Grenada, Hancock, Harrison, Hinds, 
Jackson, Jefferson Davis, Jones, Lamar, Montgomery, Pearl River, Perry, Pike, 
Rankin, Simpson, Stone. 

North Carolina : Anson, Bladen, Brunswick, Cumberland, Craven, Duplin, Jones, 
Lenoir, New Hanover, Onslow, Pender, Robeson, Sampson, Wayne, Union. 

South Carolina : Richland, Fairfield. 

The white-fringed beetle is native to Argentina, Chile and Uruguay 
in South America. It has been introduced into the United States and also 
into Australia (9, 147). 

Larvae of the white-fringed beetle feed upon underground parts of 
peanuts and damage the stand and yield. Adults feed upon the foliage. 
Uncontrolled, heavy infestation may cause a complete loss of the peanut 
crop. One report (170) showed an average of 283 larvae per square yard 
in peanut fields and upon emergence as high as 44 adults on one plant. 
In addition to peanuts, the insect feeds upon several hundred other species 
of plants," including cotton, velvetbean, soybean, lespedeza, lima bean, 
okra, sweet potato, cowpea, chufa, corn, tomato, clovers, many orna- 
mentals, and numerous other cultivated and wild plants. 

Description of stages. The adult white-fringed beetle was originally 

i» 1948. 

U- Two hundred thirty- four specimens in one locality in Alabama (147). 



INSECT PESTS 237 

described in 1840 by Boheman as Naupactus leucoloma. In 1939, 
Buchanan (20) placed the insect in the genus Pantomorus and described 
it from specimens collected at Florala, Alabama. Very brief descriptions 
of the egg and larva have been made by several investigators. 

Egg 

The egg is approximately 0.9 mm. long and 0.8 mm. wide, and is oval in shape. 
The color when freshly deposited is milky white; the color changes to dull light 
yellow after 4 or 5 days. 

The eggs are deposited in masses, ranging in number from a few to as high 
as 60 or more, but the usual number is from 15 to 25. The individual eggs and 
masses are covered with a gelatinous substance which makes them adhere to one 
another and to objects or the soil. — Young et al. (170). 

Detailed technical descriptions of the larva are not available to the 
writer. A very brief description by Young et al. (170) follows: 
Larva 

The full-grown larva averages approximately one-half inch in length. The body 
is yellowish white, fleshy, more or less curved, legless, and sparsely covered with 
hair. It consists of 12 much-folded segments, which are interrupted by two sub- 
lateral longitudinal grooves running the length of the body. The dorsal portions of 
the segments are bulging; the ventral portions are flat. On the sides, above the 
longitudinal separating grooves, small spiracles are present on all segments except 
the second, third, and twelfth (last). 

Anderson (2) has published a key with drawings for separating 
Naupactus (Pantomorus) leucoloma from related species. This key is 
reproduced below : 

1. With a group of several spinules dorsally on stipes at proximal end of the 

longitudinal row of strong setae of maxillary mala 2 

Without spinules at proximal end of the longitudinal row of strong setae of 
maxillary mala Pantomorus godmani (Cr.) 

2. Eusternum of mesothorax with minute spinules^^ between and behind the two 

sternal setae. Scutellar setae I, II, and IV on the first four abdominal seg- 
ments slender and awl-shaped {^= subulate) Artijms texamis Pierce 

Eusternum of mesothorax without minute spinules. i^ Scutellar setae I, 
II, and IV on the first four abdominal segments stout and spindle- 
shaped (= fusiform) i 3 

3. Margin of posterior third of head capsule broadly arched. Paired epipharyngeal 

scleroma distinctly U-shaped, basal part with distinct anterior margin which 
forms a clear-cut angle with exterior margin of inner arm, and with inner 
arm about twice as long as antero-poster^br extent of base .. Naupactus, n. sp. 
Margin of posterior third of head cai|pule ogival. Paired epipharyngeal 
sclerome not distinctly U-shaped, basal p^rt with obliterated anterior margin, 
exterior margin of inner arm roundly connected with interior margin of 

^2 The presence or absence of these spinules can be ascertained readily on specimens treated 
with caustic potash and on uncleared specimens when properly lighted, by studying them with a 
magnification of about 75 diameters. i 



238 THE PEANUT— THE UNPREDICTABLE LEGUME 

outer arm, and with inner arm not longer than antero-posterior extent of 
base NaUfpactus leucoloma Boh. 

Adult 
Buchanan's 1939 description of the adult follows : 

Length, 8-12 mm. Brownish gray to gray, apical declivity of elytron usually 
paler than disk, the latter sometimes indistinctly variegated with gray and pale 
brown. Scales moderately dense, setae long and conspicuous, elytral scales in general 
broader than those on head and pronotum; elytral setae of unequal lengths, the 
longer ones fine, often somewhat kinky apically in dried specimens and two or 
three times as long as the shorter ones, the latter brown to whitish ; elytral puncture 
rows, at low magnifications, appearing as narrow, dark lines. 

Vestiture on head and rostrum brownish in general, white above and below eye 
and on side of rostrum below scrobe, the scales on subapical area and on mandible 
very small, often somewhat coppery or greenish, the setae on front inclined, those 
above eye and on rostrum above suberect; nasal plate with its posterior margin 
elevated; median groove much widened anteriorly, the widest portion sometimes 
about one-fourth width of dorsum of rostrum; scape reaching hind margin of eye, 
funicular segment 2 considerably longer than 1, often nearly twice as long, longer 
than 3 and 4 together; eye distinctly elliptical. Prothorax wider than long (about 
7 to 5), sides broadly and subevenly rounded; pronotum with broader white and 
narrower brownish scales, the white ones forming a narrow, median line toward 
apex and base (rarely complete), a curved, often indistinct, stripe beginning oppo- 
site elytral interval 3, and a lateral stripe which is often incomplete anteriorly, the 
disk sometimes with small, vague, scattered, whitish spots; pronotal setae curved, 
inclined on disk, more nearly erect laterally; pronotum (with scales removed) 
irregularly punctate and feebly rugo-granulate, median groove feeble or obsolescent. 
Elytral intervals faintly convex, each with about 3 or 4 confused rows of setae, the 
longer ones more abundant on apical declivity, the length of each longer seta equal 
to or greater than the width of the interval ; white stripe covering interval 7 through- 
out, about apical two-fifths of interval 6, and basal half or more of interval 8, the 
stripe bordered mesad (on striae 5 and 6) by a broken, usually indistinct dark line, 
and bordered laterad (on stria 8) by a narrow, blackish line. Body beneath scaly and 
setose, the setae longer and more nearly erect medially, the abdominal scales pro- 
gressively finer from base to apex, abdominal vestiture sparser medially; metaster- 
num a little longer than in peregrinus. Legs with abundant, mostly setalike, prostrate 
and suberect vestiture ; fore tibia with short, well separated denticulations ; posterior 
face of hind tibia with a usually distinct ridge from base to about middle. 

Biology. Only one generation of the white-fringed beetle occurs an- 
nually. The eggs are deposited on the surface of the ground, usually on 
or next to debris (sometimes in the soil) during the summer and fall. All 
adults are females and each beetle deposits an average of slightly less than 
800 eggs. The eggs develop parthenogenetically, hatching in about 2 
weeks during warm weather. The larvae pass the winter in the soil and 
cause damage to crops, principally the following spring and summer. 
It is at this time the stand of peanuts may be seriously damaged. Adults 



INSECT PESTS 239 

emerge from May until November (169), the peak of emergence coming 
in July. Rainfall stimulates emergence. The beetles feed a few days and 
gradually disperse over the nearby areas. Since the elytra are fused to- 
gether and the insect cannot fly, dispersal is by crawling and the distance 
traveled is less than 1 mile. Eggs are deposited and the adults die 2 or 3 
months after emergence. Apparently few beetles over-winter in southern 
Alabama (169, 170) but adults have been found throughout the winter in 
the vicinity of New Orleans, Louisiana (91). 

Control. Natural enemies are apparently of minor importance in con- 
trol of white-fringed beetles. Strong (141) reported that no natural en- 
emies of P- leucoloma had been found in studies through 1938-39. Glaser 
et al. (61 ) reported a nematode, Neoaplectana glaseri Steiner, parasitizing 
P. leucoloma and related insects. Swain (142) reported A'^. glazeri attack- 
ing P. peregrinus and P. leucoloma; also N. chresima Steiner in P. pere- 
grinus. 'Later he reported (143) Diplogaster sp. capable of parasitizing 
white-fringed beetles, but of minor importance. 

Much of the first control work on white-fringed beetle was in the 
nature of locating infestations, confining the insect in local areas, sup- 
pressing and, if possible, eradicating it. Federal and State quarantines 
have been in force and clean-up campaigns have been conducted. Research 
stations have been established at Florala, Alabama; Gulfport, Missis- 
sippi ; New Orleans, Louisiana ; Fort Valley, Georgia ; and other local- 
ities, by the U.S. Bureau of Entomology and Plant Quarantine in co- 
operation with State agencies. 

Much progress has been made in the control of this insect on peanuts 
and other crops in recent years. Calcium arsenate and cryolite dusts, 
clean cultivations, herbicides for the destruction of wild host plants, and 
the use of soil fumigants such as methyl bromide and carbon disulfide 
were among the first control recommendations (111). More recently 
DDT has shown great promise. DDT has been reported (166) to be 69 
to 74 times as effective as cryolite. As little as 0.125 pound of DDT per 
100 gallons of spray gave a higher kill on peanut foliage than 12.5 pounds 
of cryolite (165). In experiments at Florala, Alabama, (167, 168) 5 
pounds technical DDT per acre, in the form of a dust or dissolved in 
zylol and mixed with the upper 3 inches of soil, gave complete mortality 
of newly hatched larvae. Smaller dosages gave complete mortality of 
summer-hatched larvae, but not of those hatched in late fall. When mixed 
with the soil at the rate of 10 pounds per acre and above, DDT gave 
complete mortality of newly hatched larvae the year following application, 
i.e., the second year. In the presence of white-fringed beetle larvae, pea- 



240 THE PEANUT— THE UNPREDICTABLE LEGUME 

nut plants on soil treated with DDT at rates of 25, 50 and 100 pounds 
per acre, yielded 48 percent more peanuts than those on untreated soil. 
Thus it appears that control of white-fringed beetle on peanuts by treat- 
ment of the soil with DDT is feasible. Dusting the foliage of peanuts to 
kill the adults is also feasible but, where soil treatments are employed, 
may not be necessary. Incidental control may be had by dusting for con- 
trol of potato leafhopper. 

Information available on the control of white-fringed beetle has been 
summarized (68). DDT is the most effective insecticidal treatment 
known for control of the pest. It may be applied to the soil for control of 
larvae or to the foliage of plants for control of adults. Ten pounds of 
technical DDT per acre has remained effective in the soil during a 5-year 
period, and the tests are still in progress to determine the length of 
effectiveness. 

The insecticide may be applied as dusts or sprays. For spraying, 50' 
percent wettable powder in concentrations of 2.5 to 5 percent has been 
most effective. 

In treatment of foliage to kill adults of the white-fringed beetle, DDT 
should be applied at the rate of J^ to 1 pound of technical per acre at 
2- to 3-week intervals during the season of beetle emergence. The insec- 
ticide may be applied in the form of dusts or sprays. Sprays are usually 
prepared from wettable powder or emulsifiable concentrates. 

Since the major part of the research on white-fringed beetle is being 
conducted by the U. S. Bureau of Entomology and Plant Quarantine, this 
agency should be consulted for latest recommendations on control. 

Only limited information is available on the effect of rotation and 
other cropping practices on control of the white-fringed beetle. Additional 
research is needed on these points. Additional information is also needed 
on the long-time effect of soil treatments with DDT on productivity, soil 
organisms, fish and wildlife, and water supplies. 

Soil Insects 

Several species of soil insects attack peanuts and cause an undeter- 
mined amount of damage. In addition to the white-fringed beetle, which is 
discussed in another section, damage to underground parts is caused by 
several species, including soutliern corn rootworm, larvae of the banded 
cucumber beetle, two species of wireworms, white grubs, and the lesser 
cornstalk borer. 

One of the first references of damage to peanuts by soil insects was 
made by Fink (56), who found southern corn rootworm, Diabrotica du- 



INSECT PESTS 



241 



odecimpimctata (F), attacking young peanut pods in Virginia; the nuts 
within the pods were devoured. Following this report, peanut damage 
from this insect received little attention until recent years. An average of 
12 to 28.1 percent of the pods was reported as injured during 1945 and 
1946 in a study made in Virginia (64) . D. duodecimpunctata and larvae 
of the related species, D. balteata Lee, were found attacking peanut pods 
in Alabama ( 5) . Because of the difficulty of distinguishing between the two 
closely related species of larvae, no attempt was made to determine rela- 
tive abundance. However, the large number of recently transformed D. 
balteata adults found in pupal cells in the soil around the peanuts indi- 
cated this species was the predominant one. In 1947 Arant (5) observed 
as high as 35 percent of the pods injured in some fields, but in this in- 
stance a wireworm, Heteroderes sp. appeared to be doing much of the 
damage. Other soil pests appear to be of less importance. 




Figure 4. Peanut pods damaged by soil insects (wireworms and Diabrotica larvae.) 



242 THE PEANUT— THE UNPREDICTABLE LEGUME 

Southern Corn Rootworm. This insect is the larva of a 12-spotted 
leafbeetle, Diabrotica duodecimpunctata (F), commonly called the 
spotted cucumber beetle. The life history and habits of the insect are well 
known (144, 82, 4, 137). Both adults and larvae arc polyphagic in their 
feeding habits, several hundred species of plants serving as hosts. The 
foliage of cucurbits and many of the legumes are among the preferred foods 
of adults. Eggs are deposited in the soil and the larvae develop upon un- 
derground parts of many plants including young corn and the pods of 
peanuts. The time for development from egg to adult is 30 to 40 days dur- 
ing warm weather. Adults over-winter only in the Southern States. Dur- 
ing the summer months, many adults migrate northward and cause dam- 
age to cucurbits and other crops. 

The extent of the damage caused by this species to peanuts has not 
been clearly evaluated. Apparently the insect is more destructive in Vir- 
ginia than in Alabama. 

Banded Cucumber Beetle. The banded cucumber beetle, D. balteata 
Lee. is a pest of beans, vetches, cucurbits, alfalfa, tomatoes and many 
other vegetables, fruits and ornamental plants. It is restricted to warm 
climates, occurring in the U. S. in the Gulf Coast States and California. 
It is distributed in Alabama from the central part of the State south- 
ward (127). The insect is found in the northern extremities of its range 
only in late summer and fall. 

The banded cucumber beetle has been known in Mexico for many 
years. In 1905 it was found in Texas (29) and in 1922 in Alabama ( 127) . 
Little is known regarding the habits of the larva. It will feed on under- 
ground parts of peanuts, corn, sti;ing beans, and doubtless many other 
plants. Using corn as food for the larvae Robinson (128) found that 
approximately 30 days were required for development from egg to adult 
during warm weather. The number of generations, seasonal abundance, 
overwintering habits, and food preferences of larvae and adults in the 
peanut-growing areas are largely unknown. There is a need for ad- 
ditional research on this insect and an evaluation of its damage to peanuts. 

Wireworms. Wireworms of the genus Heteroderes^^ were found by 
the writer damaging peanut pods in Alabama in 1947. Larvae of the 
genus Cebria}^ were also collected from peanuts. 

The wireworm, Heteroderes laurentii Guer., is widely distributed in 
the Southeastern States and causes economic damage to a variety of 
crops, including corn, snapbeans, potatoes, lespedeza and sweet potatoes 
(31). So far as the writer is aware, there is no record of damage from 
Cebria sp. in Alabama or adjoining States. 

" Identification by Dr. W. H. Anderson, U. S. Bureau of Entomology and Plant Quarantine. 



INSECT PESTS 243 

Although definite proof is lacking, it is probable that H. laurentii 
is the species which attacks peanuts. Unlike some wireworms, this 
species completes its development within one year. It prefers cultivated 
lands to sod areas. This and other species of the genus Heteroderes are 
limited to tropical and subtropical areas (87). 

The major facts regarding wireworm damage to peanuts are yet to 
be determined. 

White Grubs. The larvae of Strigoderma arboricola (F.), have been 
reported doing serious damage to peanuts in Virginia (105). The grubs 
attacked the peanut pods and often devoured the nuts. Soil fungi 
{Rhizoctonia) apparently invaded the pods through abrasions in the shell 
and caused rotting of the peanuts. The damage was more severe on soils 
fairly high in organic matter. The grubs caused 85 percent loss in some 
fields. 

The adult of these grubs is a beetle (Rutelid) 10 to 12 mm. long. The 
head, thorax and scutellum are blackish green in color and the elytra are 
dull brownish yellow ( 18) . The beetles feed on the flowers of wild and 
cultivated roses and on blackberry blossoms and fruits. On collecting 
adults from many other plants, Grayson (63) concluded that neither 
the larva nor the adult was host specific for peanuts, and that grub dam- 
age to peanuts in Virginia was of a minor nature during 1944 and 1945. 

Lesser Cornstalk Borer. The lesser cornstalk borer, Elasmo palpus 
lignosellus (Zell.), is widely distributed over southern United States, 
Mexico and South America. The larva is slender and greenish. in color 
with indistinct transverse bands of a lighter color on the anterior margin 
of each segment ; it is usually a little less than one inch long when mature. 
The adult is a yellowish brown to blackish-colored moth with a wing 
expanse slightly less than one inch. 

The larva feeds on corn, beans, cowpeas, s^jgar cane, peanuts, 
sorghum and many other crops. Damage is caused by the insect tunnelling 
in the stem of the host plant. When not feeding, the larva usually rests in 
a tube-shaped web near the surface of the soil. Crops on thin sandy soils 
are injured most seriously. Four generations a year have been reported 
in South Carolina and Mississippi, each requiring 4 to 5 weeks (94, 95). 

There is a strong belief in southern Alabama that the lesser cornstalk 
borer is a serious pest of peanuts. Presumably the pest bores in the 
stems, killing branches or entire plants. During two seasons, the writer 
has not been able to find any serious damage to peanuts which could be 
definitely attributed to lesser cornstalk borer. It is well known, however, 
that the population of this species reaches destructive levels only at inter- 



244 THE PEANUT— THE UNPREDICTABLE LEGUME 

vals over a period of years (95). It is possible that serious destruction 
does occur during some seasons. 

Other Soil Insects. Several insects not previously discussed are re- 
corded in the literature as attacking the pods and underground parts of 
peanuts. These records include the following: Japanese beetle, Popillia 
japonica Newn., attacking peanuts in Japan (159) and a potential pest in 
the United States ; termites in many parts of the world ; a mealybug, 
Pseudococcus sp. on peanut roots causing severe damage in Puerto Rico 
(138) ; mealybug, P. solani Ckll., occurring on peanut roots but causing 
little damage in Florida (23) ; pineapple mealybug, P. hrevipes (Ckll.) on 
peanut pods in Tanganyika (67) ; citrus mealybug, P citri (Risso), and 
also Phenacoccus hirsutus Green on roots of peanuts in Egypt (78) ; 
larvae of the yam beetle, Heteroligus Claudius Klug., killing as high as 70 
percent of seedling peanuts in the Province of Nigeria (88) ; iwo ants, 
Solenopsis jugax Latr. and Tetramorium coespitum L., a mole cricket, 
Gryllotalpa gryllotalpa L., and three species of beetle larvae, Pentodon 
idiota Hbst., Agriotes gurgistanus Fald., and Podonta daghestanica Reitt 
in North Caucasus ( 132) ; the mole crickets, Scapteriscits acletus R. & H. 
and 5". vicinus Scudd., on peanuts in southeastern United States (163) ; 
two ants, Eciton caeca Latr. and Ectatomma ruidiim Roger, in Central 
America (21) ; the earwig, Euborellia stali Dohrn, causing as high as 20 
percent damage to peanut pods in southern India (25) ; several species 
in Senegal including termites, Termes natalensis Hav. and T. bellicosus 
Semath which gnaw pods, and Odontotermes vulgaris Hav. which attacks 
the nuts themselves ; white grubs, Schizoncha africana Cast., Anomala 
pleheja Ol., Adoretus umbrosus F., and Podalgus (Crator) cunicidus at- 
tacking underground parts ; the beetle, Scydmaenus chevalieri boring 
into pods and the ants, Monomorium hicolor Em. and Dorylus julvus 
Westu. eating seeds of perforated pods (131). 

Control. Few studies have been made on control of insects attacking 
underground parts of peanuts. Soil treatment with DDT and benzene 
hexachloride has been found to reduce southern corn rootworm injury 
to corn (60). Results of control experiments on southern corn rootworm 
on peanuts in Virginia (64) showed that DDT applied to the soil at the 
rate of 50 pounds of technical material per acre resulted in a reduction of 
61 to 68 percent in the number of pods injured ; yield records were not 
taken. The writer (5) found that soil treatment with DDT, BHC, chlor- 
dane and toxaphene reduced the injury to pods by soil insects on repli- 
cated plots in Alabama. In 1949, he found that dusting with toxaphene 
or DDT reduced damage from Diabrotica larvae (8). Eflfective control 



INSECT PESTS 245 

is reported by Fronk and Dobbins (59) from soil applications of 1 to 1 3^ 
pounds gamma benzene hexachloride, 5 pounds parathion, 40 pounds 
toxaphene, or 67 pounds DDT. Additional research is needed on soil 
insects, their economic status, and control. 

Insects Attacking Peanuts and Peanut Products in Storage 

A host of insects attack peanuts and peanut products in storage, some 
times causing severe damage. Some damage may occur in storage on 
farms, but the major losses are to buyers, processors, wholesalers, and re- 
tailers of peanuts and products derived from them. Insect infestations are 
much heavier in peanuts after they are shelled (121, 17). Salted peanuts, 
peanut meal, peanut butter, candies and other confections are readily in- 
fested by insects and the peanut trade must continuously combat these 
pests. 

Many of the forms infesting grain, milled products, dried fruits and 
other foods also attack peanuts. The exact number of species infesting 
peanuts is not known, but over 50 species infest grain and grain products 
(11). Among the more important stored-products pests attacking peanuts 
are Indian meal moth, almond moth, saw-toothed grain beetle, flour 
beetles, cadelle, dermestids and others. 

So far as the writer is aware, no adequate estimates are available 
on annual insect damage to peanuts and their products in storage. A 3- 
million-dollar loss in the United States was estimated in 1911 (121). In 
1943 the Food and Drug Administration (58) reported that, of the 
7 million pounds of imported nuts^* examined in 1943, over 5 million 
pounds were denied entry because they were wormy or damaged. The 
major reason for the high percentage of rejections was insect infestation 
in large shipments of peanuts from Africa. 

Different species of insects infesting stored peanuts and peanut prod- 
ucts vary greatly in actual damage caused. However, heavy insect infesta- 
tions render the products unfit for the edible trade regardless of the 
extent of destruction wrought. 

Indian Meal Moth. The Indian meal moth, Plodia inter punctella 
(Hbn.) is a handsome moth with a wing expanse of nearly % inch (11). 
The fore wings are reddish brown with a coppery luster on the apical two- 
thirds; the proximal third is whitish gray; the hind wings are dusky 
gray. The larva is a dirty^-white caterpillar often with a pinkish or green- 
ish tint ; when full-grown, it is about J4 inch long. According to Popenoe 
(121) this is the most important insect pest of stored peanuts in the 

" Several kinds, including peanuts. 



246 THE PEANUT— THE UNPREDICTABLE LEGUME 

United States. It also causes damage to peanuts in many other parts of 
the world (131, 103, 140, 109, 96, 22). Larvae of the Indian meal moth 
feed upon shelled peanuts and spin silken threads which form a matted 
web. Broken kernels are preferred by this species. 

Almond Moth. The almond moth,^^ Ephestia cautella (Walk.), 
is a pest of nuts, dried fruits and other products including peanuts. The 
adult has a wing expanse of about % inch. The fore wings are narrow, 
especially at the base, grayish to yellowish in color with dark markings 
which may appear as zigzag lines or suffused bands across the wings ; hind 
wings are whitish (30). The larva is a whitish caterpillar which may be 
tinged with pink and green ; it is cylindrical and about J4 inch long when 
fuUgrown; dark dots in four pairs of rows give the body a striated ap- 
pearance. The larvae spin silken webs which may appear as masses inter- 
mingled with food and excrement. In 1911 peanuts were listed (30) as a 
stored product attacked by larvae of the almond moth. Since then this 
species has been found causing economic damage to peanuts in many 
sections of the world. Almond moth has been reported (17) as very de- 
structive in Georgia. Other reports include those for Senegal (131), 
Spain (134), Gold Coast (33) and Britain (62). 

Saw-toothed Grain Beetle. Both larvae and adults of the saw-toothed 
grain beetle, Orysaephilus surinamensis (L.), attack peanuts and prod- 
ucts derived from them. Bissel and DuPree (17), found this insect to be 
the most abundant species-'^® in shelled peanuts in Georgia; Popenoe 
(121) listed it third in importance among stored peanut pests. It is 
recorded infesting peanuts in other parts of the world (10, 130). The 
adult saw -toothed beetle is about 1/10 inch long and brownish in color ; 
the thorax bears 6 saw-tooth-like projections on each side. The whitish 
larva has a brown head, is small, slender, and slightly longer than the 
adult. Adults of the saw-toothed grain beetle have been kept alive over 3 
years ; the average life is 6 to 10 months. Two related species, 0. bicornis 
(Er.) and 0. mercator (Fauv.) occur in this country. The latter species 
is known to infest peanuts in Senegal (131). Both have feeding habits 
similar to that of 0. surinamensis. 

Flour Beetles. At least two species of flour beetles of the Genus 
Tribolium attack stored peanuts and products derived from them. The 
red ilour beetle, T. castaneum (Hbst.), and confused flour beetle, T. 
confusum Duv., were fairly numerous in shelled peanuts (17). The 
former species has been considered (121) as second in importance among 

^ Also called fig moth. 
1* Other than psocids. 



INSECT PESTS 247 

stored peanut pests in the United States. The two forms have been 
recorded in peanuts from other parts of the world (Roubaud, (131), T. 
castaneum and confusum in Senegal; Jarvis, (83), T. castaneum in 
Australia; Fletcher, (57) and Roepke, (130), Tribolium sp. in Pusa 
and Java; Okuni, (110), T. castaneum in Formosa). The flour beetles 
are elongate, reddish-brown insects about 1/7 inch long. The larvae are 
brownish white and somewhat flattened in appearance. Adults of the two 
species may be distinguished by the following differences : 

As viewed from the underside of the head, the eyes of the confused flour beetle 
are separated by about three times the width of either eye, whereas the width of 
each eye as seen from below in the red flour beetle is about equal to the distance 
between them. The confused flour beetle has antennae gradually enlarged toward 
the tip, the red flour beetle suddenly enlarged at the tip; the margin of the head 
is notched at the eyes in the confused flour beetle and not so notched in other species. 
(101). 

Adult flour beetles may live 2 years or more, but the average life 
is about 1 year (11). 

Cadelle. The cadelle beetle, Tenehr aides mauritanicus (L.), appears 
to be of importance in peanuts, although literature references to infesta- 
tions are scarce. It has been listed (121) as fourth in importance among 
stored peanut pests, and has been found to be one of the more common 
forms in shelled peanuts stored in jute bags (17). Roubaud (131) re- 
ported it infesting stored peanuts in Senegal. The adult is an oblong, flat- 
tened beetle, black in color and measuring about 1/3 inch in length. The 
larva is dirty-white with the head, thoracic shield, and two horny points at 
the tip of the abdomen black ; it is about % inch long when full-grown. 
This insect is primarily a pest of grain and flour mills. The larvae some- 
times bore into wood. Average life of the adult is 1 to 2 years. The extent 
of its damage to peanuts needs further investigation. 

Dermestids. Several species of dermestids infest peanuts. Among the 
forms recorded in the literature are Trogoderma bicolor Arrow in peanuts 
imported into Holland (24) ; Dermestes lardarius L. in peanuts in Europe 
(173) ; Attagenus gloriosae imported into Holland (not established) in 
peanuts (74) ; unidentified species of dermestids common in shelled 
peanuts stored in jute bags in Georgia (17). The dermestids are small 
beetles that are for the most part scavengers, feeding upon animal matter. 
Forms that feed on plant products probably supplement the diet with 
dead bodies of other insects (11). Thus, it would appear that the 



248 THE PEANUT— THE UNPREDICTABLE LEGUME 

principal damage to peanuts by these pests might be spoilage of products 
intended for the edible trade. 

Other Pests of Stored Peanuts. The Mediterranean flour moth, 
Ephestia kuehniella Zell. may cause economic damage to peanuts. Larvae 
of this species were considered by Popenoe (121) as sixth in importance 
among stored peanut insects. However, the writer has found no ad- 
ditional references to this insect infesting peanuts, although it is 
distributed over many parts of the world. 

Bruchids attack peanuts in storage, mostly in foreign countries. 
Bruchus chinensis L. attacks peanuts in Java ( 129) . Pachymerus acaciae 
Gyll. is reported (40) as infesting peanuts and as having spread from 
Asia to Greece, Italy and the north and west Coasts of Africa. This 
species is recorded as attacking stored peanuts in Senegal (26) with 
59,000 tons of peanuts being destroyed by it ( 145) . Howard (79) referred 
in a general way to fumigation as a means of protecting peanuts against 
pea and bean weevils. However, this is the only reference found indicating 
bruchid injury to peanuts in the United States and it is concluded that 
such damage is not common. 

The flat grain beetle, Laemophloeus minutus (Oliv.), a sap beetle, 
Carpophilus sp., the cigarette beetle, Lasioderma serricorne (F) and 
numerous psosids were found (17) in stored peanuts in Georgia and 
were suspected of being injurious. Other reports include a sap beetle, 
Carpophilus sp., in peanuts in Australia (83) ; a relative of cigarette 
beetle, Lasioderma testaceum in peanut cake in Pusa; sap beetles, C. 
ligneus Murr., C. hemipterus L., and C. decipens, attacking peanuts in 
Europe (172) and C. obsoletus in Japan (75). All of these insects are 
cosmopolitan in distribution. With the exception of the cigarette beetle, 
they are probably incapable of damaging sound peanut kernels but may 
thrive in peanuts already damaged by other insects or in certain products 
derived from peanuts. 

Five hundred tons of peanuts, imported into California from China, 
were reported as destroyed by Aphomia gularis Zell. of the family 
Galleridae (43). This species closely resembles Mediterranean flour 
moth. 

Additional reports of infestation in peanuts include the following: 
Tobacco (currant) moth, Ephestia elutella (Hbn.), injuring peanuts in 
Zomba (99), infesting peanut cake in Senegal (84) and in France 
(85), and infesting peanuts imported into California from China (44) ; 
Sitophilus oryza (L.) in shelled peanuts in Fiji (90) and in Georgia 
(17); Alphitobius diaperinus (Panz.), A. piceus 01., and Corcyra 



INSECT PESTS 249 

cephalonica Staint. in Senegal (131) ; Homoeosoma vagella Z. in Aus- 
tralia ; Embia (Monotylota) vayssierei Navas in stored peanuts in Sene- 
gal (123); Sitotroga cerealella (Oliv.), Angoumois grain moth, and 
Tenebrio sp., (meal worm) in stored peanuts in the United States (17). 

Control. Natural enemies are of value in controlling pests of stored 
peanuts, but the species of hosts and parasites involved are so numerous 
and varied that a detailed discussion here is not feasible. Among the 
more important parasitic and predaceous forms are Microbracon hebetor 
(Say), M. jugeandis Ashm., Idechthis canescens (Grav.), Omorgus 
jrumentarius Rond., and Scenopinus fenestralis (L.) (136, 11). 

Sanitation and proper bagging have been found helpful in preventing 
insect damage to stored peanuts. Bissell and DuPree (17) found that 
peanuts could be protected from serious infestation by storing them im- 
mediately after shelling in cotton bags made from heavy material having 
60 threads by 104 threads per inch. Jute bags counting 11 or 12 threads 
per inch did not give satisfactory protection. For maximum protection, 
properly bagged peanuts should be stored in clean, insect-free bins. To 
free bins, storehouses, boxcars and the like of insects, the walls, floors 
and ceilings may be sprayed with DDT in a 5 percent solution in light oil 
(36, 37) or in the form of a 5 percent emulsion in water. 

Heat and cold have been employed satisfactorily in preventing insect 
damage to peanuts and peanut products in storage. It was found (19) 
that a temperature of 125° F. for 6 hours destroyed insects in loose piles 
of dry peanuts without injury to the peanuts. Also it was reported (36) 
that a temperature of 120° to 130° F. maintained in all parts of flour mills 
for 10 to 12 hours destroyed all insect life. Forced circulation of air was 
necessary to maintain proper temperature throughout the treated area. 
The use of heat is limited by facilities for maintaining suitable tempera- 
tures within masses of stored products. Refrigeration is also effective 
in preventing insect damage. Protection against insect infestations has 
been reported when peanuts and peanut products are stored at 50° F. 
or below ( 164) . The keeping qualities of the products were also enhanced. 

Fumigation is perhaps the most feasible method of destroying insects 
in stored peanuts, once they are infested. Materials which have been used 
for this purpose include carbon disulfide and hydrogen cyanide (19, 33), 
a mixture consisting of three parts ethylene dichloride and one part 
carbon tetrachloride (80), ethylene oxide, 4 ounces plus 2.8 pounds of 
carbon dioxide per 100 cubic feet in a vacuum tank filled with peanuts 
(34), and methyl bromide (97, 139). Chloropicrin has been found efifec- 
tive, but it is absorbed and increases the acid content of the peanuts as 



250 THE PEANUT— THE UNPREDICTABLE LEGUME 

much as 300 percent (40) ; absorption may be reduced by using carbon 
dioxide with a smaller dose of chloropicrin (34). 

Of the several fumigants in common usage, methyl bromide is prob- 
ably the most desirable for fumigating peanuts and peanut products, 
provided tight masonry storehouses, vaults or fumigation chambers are 
available. This gas is noninflammable, is highly toxic to insects, and 
penetrates well into bagged commodities or other masses of stored prod- 
ucts. It is highly toxic to warm-blooded animals and is almost odorless. 
Well-trained personnel are required for fumigation with methyl bromide. 
The gas is usually introduced through pipes or tubes from cylinders of 
the liquid material, placed outside. The rate of application is 1 to 1>4 
pounds per 1,000 cubic feet where masses of stored products must be 
penetrated. After an exposure of approximately 24 hours, the chamber 
should be ventilated. In general, metal and wooden buildings are not suit- 
able for fumigation with this material. For additional information on the 
use of methyl bromide, the reader is referred to the Supplement to 
USDA Circular 390 (39) and to USDA Circular 720 (37). 

Stored peanuts in tightly constructed metal or wooden buildings may 
be fumigated with a grain fumigant containing three parts ethylene 
dichloride and one part carbon tetrachloride, applied at the rate of 4 to 
5 gallons per 1,000 bushels of stored product (35). 

A considerable amount of the information on control of insects in 
stored peanuts was developed by research on these pests in other products. 
Additional research is needed, particularly on the effect of fumigants, 
refrigeration and heat treatment on peanuts and peanut products as well 
as the insects involved. 

Miscellaneous Pests 

In addition to the insects discussed in this paper, numerous minor 
pests have been observed attacking peanuts in various parts of the world. 
No attempt is made to cover all of these pests, and no claim is made that 
the publication is in any sense complete. 

SELECTED REFERENCES 

(1) ACKERMAN, A. J. AND ISELY, DWIGHT. 

193L THE LEAFHOPPERS ATTACKING APPLE IN THE OZARKS. U. S. Dept. Agr. 

Tech. Bui. 263, 40 pp. 

(2) Anderson, W. H. 

1938. A KEY TO separate THE LARVA OF THE WHITE-FRINGED BEETLE, 

Naupactus leucoloma boh., from the larvae of closely related 
SPECIES. U. 8. Dept. Agr. Bur. Ent. and Plant Quarantine. E-422, 
3 pp. 



INSECT PESTS 251 

(3) Anderson, L. D. and Walker, H. G. 

1940. NOTES ON THE CONTROL OF ONION THRips. Jour. Econ. Ent. 33 (2): 
278-280. 

(4) Arant, F. S. 

1929. BIOLOGY and control of the southern corn rqotworm. Ala. Agr. 
Expt. Sta. Bui. 230, 46 pp. 
(5) 

(6) 



1946, 1947, 1948, 1949. unpublished data. Ala. Agr. Expt. Sta. 



1948a. status of velvetbean caterpillar control in Alabama. Jour. 
Econ. Ent. 41 (1) :26-30. 



(7) 

1948b. control of peanut insects. Ann. Rpt. Ala. Agr. Expt. Sta. 58 

and 59:43-44. 

(8) 

1949. control of peanut insects. Ann. Rpt. Ala. Agr. Expt. Sta. 

(9) Anon. 

1933. review applied entomology 21:303. 

(10) Azemard. 

1914. LES INSECTES PARASITES DES ARACHIDES AU SENEGAL. L'Agron. ColOH. 

10:106-110. 

(11) Back, E. A. and Cotton, R. T. 

1938. STORED GRAIN PESTS. U. S. Dept. Agr. Farmers Bui. 1260, 48 pp. 

(12) Ball, E. D. 

1919. the potato leafhopper and its relation to hopperburn. jour. 
Econ. Ent. 12 (2):149-154. 

(13) Barber, G. W. 

1936. METHOD OF REARING CORN EARWORM LARVAE. Jour. Econ. Ent. 29 (6) : 

1175-1176. 

(14) Batten, E. T. and Poos, F. W. 

1938. Spraying and dusting to control the potato leafhopper on 
PEANUTS IN VIRGINIA. Va. Agr. Expt. Sta. Bui. 316, 26 pp. 

(15) Beyer, A. H. 

1922. experiments on the biology and TIPBURN disease of the BEAN 
LEAFHOPPER WITH METHODS OF CONTROL. JoUr. Econ. Ent. 15 (4): 

298-302. 

(16) BissELL, T. L. AND Alden, C. H. 

1945. CONTROL OF INSECT PESTS OF PEANUTS IN THE FIELD. Ga. Agr. Expt. 

Sta. Press Bui. 546. 

(17) AND DuPree, M. 

1946. INSECTS IN SHELLED PEANUTS IN RELATION TO STORAGE AND BAGGING. 

Jour. Econ. Ent. 39 (4):550-S52. 

(18) Blatchley, W. S. 

1910. COLEOPTERA OR BEETLES KNOWN TO OCCUR IN INDIANA. The Nature 

Publishing Co., Indianapolis, 1386 pp. 

(19) BRiDvreLL, J. C. 

1918. INSECTS IN RELATION TO PROBLEMS OF STORAGE OF FOOD IN HAWAII. 

Proc. Hawaiian Ent. Soc. 3 (5) :506-509. 



252 THE PEANUT— THE UNPREDICTABLE LEGUME 

(20) Buchanan, L. L. 

1939. THE SPECIES OF Pantomofus of America north of Mexico. U. S. Dept. 

Agr. Misc. Pub. 341, 40 pp. 

(21) Calderon, S. 

1931. insect conditions in Salvador, central America. Insect Pest Survey 
Bui. 11 (10):686-688. 

(22) Candura, G. S. 

1937. studi SUGLI insetti dannosi ai semie e ai viveri nella venezia 
tridentina l. comportamento biologico della plodia inter- 
punctella. KB. Studi Trentini 18 (3):263-315. 

(23) Chaffin, J. 

1921. mealybugs. Quart. Bui. Fla. St. PI. Bd. 5 (3):154-1S8. 

(24) Champion, G. C. 

1923. NOTES on Trogoderma Granarium everts (t. Khapra, arrow) and 
T. tricolor arrow. Ent. Mo. Mag. 59:111. 

(25) ChERIAN, M. C. AND Basheer, M. 

1940. Euborellia stall dohrn (forficulidae) as a pest of groundnut in 

south INDIA. Indian Jour. Ent. 2 (Pt. 2):155-158. 

(26) Chevalier, A. 

1936. l'arachide au Senegal. Rev. Bot. Appl. 16 (181-2) :673-872. 

(27) Chittenden, F. H. 

1901. fall armyworm and variegated cutworm. U. S. Dept. Agr. Div. 
of Ent. Bui. (New Series) 29. 



1905. THE caterpillar of Anticarsia gemmalilis injuring velvetbean. 
U. S. Dept. Agr. Bur. Ent. Bui. 54:77-79. 



1910. notes on the cucumber beetles. U. S. Dept. Agr. Bur. Ent. Bui. 
82 (Pt. IV):67-75. 



(28) 

(29) 

(30) 

1511. THE FIG MOTH. U. S. Dept. Agr. Bur. Ent. Bui. 104:1-40. 

(31) Cockerham, K. L. and Deen, O. T. 

1936. NOTES ON LIFE HISTORY, HABITS AND DISTRIBUTION OF HeterodcreS 

laurentii GUER. Jour. Econ. Ent. 29 (2) :288-296. 

(32) CORBETT, G. H. 

1920. OBSERVATIONS ON COTTON THRIPS IN THE GEZIRA BLUE NILE PROVINCE 

OF SUDAN IN 1918-1919. Bul. Ent. Res. (London) 11 (2):95-100. 

(33) COTTERELL, G. S. 

1934. INFESTATION OF STORED COCOA BY WEEVIL (Araecerus fasctculatus) AND 
MOTH {Ephestia cautelld). Bul. Dept. Agr. Gold Coast 28, 14 pp. 

(34) Cotton, R. T. 

1930. carbon dioxide as an aid in the fumigation of certain highly 
ABSORPTIVE COMMODITIES. Jour. Econ. Ent. 23 (l):231-233. 

(35) 

1942. CONTROL OF INSECTS ATTACKING GRAIN IN FARM STORAGE. U. S. Dept. 

Agr. Farmers Bul. (Rev.) 1811, 24 pp. 

(36) Cotton, R. T., Frankenfeld, J. C. and Dean, G. A. 

1945. controlling insects in flour mills. U. S. Dept. Agr. Circ. 720, 75 pp. 



INSECT PESTS 253 

(37) CoTTON.R.T., FrankenfeldJ.C, Walkden.H.H. and Schwitzgebel, R. B. 

1945. TESTS OF DDT AGAINST THE INSECT PESTS OF STORED SEED, GRAIN AND 

MILLED CEREAL PRODUCTS. U. S. Dept. Agr. Bur. Ent. and Plant 
Quarantine. E-641, 7 pp. 

(38) Creighton, J. T. 

1939. certain aspects of the white-fringed beetle problem. Jour. Econ. 
Ent. 32 (6) -.768-780. 

(39) Dean, G. A. and Cotton, R. T. 

1943. fumigation with methyl bromide. Insert for U. S. Dept. Agr. Circ. 
390, 5 pp. 

(40) De Jonghe, d'Ardoye E. 

1935. note sur la bruche de l'arachide Pachymoerus acaciae gyll. BuI. 
Ann. Soc. Ent. Belg. 75 (Pt. ll-12):421-422. 

(41) DeLong, Dwight M. 

1931. A revision of the AMERICAN SPECIES OF Empoasca known to occur 
north of MEXICO. U. S. Dept. Agr. Tech. Bui. 231, 60 pp. 

(42) 

1938. biological studies on the leafhopper Empoasca fabae as a bean 
PEST. U. S. Dept. Agr. Tech. Bui. 618, 60 pp. 

(43) De Ong, E. R. 

1919. an imported feeder on stored peanuts. Jour. Econ. Ent. 12 (5) :407. 

(44) 

1925. THE currant moth on peanuts. Pan Pacific Ent. 2(1) :46. 

(45) Ditman, L. p. and Cory, E. N. 

1931. the corn earworm biology and control. Univ. of Md. Agr. Expt. 
Sta. Bui. 328. 

(46) Douglas, W. A. 

1930. the velvetbean caterpillar as a pest of soybeans in southern 

LOUISIANA AND TEXAS. Jour. Econ. Ent. 23 (4) -.684-690. 

(47) Dudley, H., C, Sayers, R. R. and Neal, P. A. 

1943. bromide content of certain foodstuffs fumigated with methyl 
bromide II. Proc. Pacific Sci. Congr. 6:159-163. 

(48) Eddy, C. O. 

1942. entomological progress no. 3. La. Agr. Expt. Sta. Bui. 350:17-23 
(L. O. Ellisor). 

(49) and Livingstone, E. M. 

1931. FrankUniella fusca hinds on seedling cotton. S. C. Agr. Expt. Sta. 

Bui. 271, 23 pp. 

(50) Ellisor, L. O. and Graham, L. T. 

1937. A recent pest of alfalfa. Jour. Econ. Ent. 30 (2):278-280. 

(51) and Floyd, E. H. 

1938. toxicity of several stomach-poison insecticides to four species 

OF lepidopterous larvae. Jour. Econ. Ent. 31 (1): 65-68. 

(52) English, L. L. 

1946. the velvetbean caterpillar on peanuts; control experiments. 

Jour. Econ. Ent. 39 (4):531-533. 

(53) Fabricius, J. C. 

1793. Ent. Syst. 3, 1:456-457. 



254 THE PEANUT— THE UNPREDICTABLE LEGUME 

(54) Fenton, F. a. and Hartzell, A. 

1923. BIONOMICS AND CONTROL OF THE POTATO LEAFHOPPER, EmpoaSCa mali 

(lebaron). Iowa Agr. Expt. Sta. Res. BuL 78:379-440. 

(55) Fernald, H. T. 

1935. applied entomology. McGraw-Hill, 3rd Ed. 

(56) Fink, D. E. 

1916. injury to peanuts by the twelve-spotted cucumber beetle 
(DiabroHca 12-punctata OL.). Jour. Econ. Ent. 9 (3):366-369. 

(57) Fletcher, T. B. 

1923. report of the imperial entomologist 1922-23. Sci. Rpts. Agr. Res. 
Inst. Pusa. pp. 61-75. 

(58) food and drug administration. (U. S.) Ann. Rpts. 1941-42, 1942-43. 

(59) Fronk, W. D. and Dobbins, T. N. 

1949. insecticide tests for control of the southern corn rootworm 
in peanuts. U. S. Dept. Agr. Bur. of Ent. and Plant Quarantine. 
E-782. 

(60) Fulton, B. B. 

1946. SOIL insecticides for control of the southern corn rootworm. 
Jour. Econ. Ent. 39 (6) :781-783. 

(61) Glaser, R. W., McCoy, E. E. and Girth, H. B. 

1940. the biology and economic importance of a nematode parasitic in 

INSECTS. Jour. Parasit. 26 (6) :479-495. 

(62) Golding, F. D. 

1941. TWO NEW METHODS OF TRAPPING THE CACAO MOTH (Ephestia Cautello). 

Bul. Ent. Res. 32 (Pt. 2): 123-132. 

(63) Grayson, J. M. 

1946. life history and habits of Strigoderma arhoricola. Jour. Econ. Ent. 

39 (2):163-167. 

(64) AND Poos, F. W. 

1947. southern corn rootworm as a pest of peanuts. Jour. Econ. Ent. 

40 (2):251-256. 

(65) Guyton, F. E. 

1940. an outbreak of the VELVETBEAN caterpillar in ALABAMA WITH 

DATA ON CONTROL. Jour. Econ. Ent. 55 (4) :635-639. 

(66) Harris, T.W. 

1841. A REPORT ON THE INSECTS OF MASSACHUSETTS, INJURIOUS TO VEGETA- 
TION, 459 pp. 

(67) Harris, W. V. 

1935. REPORT OF THE ASSISTANT ENTOMOLOGIST. Rpt. Dept. Agr. Tanganyika, 
1934:84-89. 

(68) Henderson, C. F. and Padget, L. J. 

1949. WHITE-FRINGED BEETLES, DISTRIBUTION, SURVEY AND CONTROL. U. S. 

Dept. of Agr., Bur. Ent. and Plant Quarantine. E-779. 

(69) Hinds, W. E. 

1902. contribution to a monograph of the insects of the order thy- 

SANOPTERA INHABITING NORTH AMERICA. PrOC. U. S. Nat. Mus. 

26:154. 

(70) 

1905. Proc. Biol. Soc. Wash. 18:197-199. 



INSECT PESTS 255 

(71) Hinds, W. E. 

1930. THE OCCURRENCE OF AuHcarsia gemmatilis as a soybean pest in 

LOUISIANA IN 1929. Jour, Econ. Ent. 23 (4):711-714, 3 plates. 

(72) AND Dew, J. A. 

1915. THE GRASS WORM OR FALL ARMY WORM. Ala. Agr. Expt. Sta. Bul. 186. 

(73) AND OSTERBERGER, B. A. 

1931. THE SOYBEAN CATERPILLAR IN LOUISIANA. JoUr. Econ. Ent. 24 (6): 

1168-1178. 

(74) HiNTON, H. E. 

1943a. NOTES ON two species of Attagenus (col. dermestidae) recently 
INTRODUCED INTO BRITAIN. Ent. Mo. Mag. 79 (953): 224-227. 

(75) 

1943b. A KEY TO THE SPECIES OF CARPOPHILUS (COL. DERMESTIDAE) THAT HAVE 
BEEN FOUND IN BRITAIN, WITH NOTES ON SOME SPECIES RECENTLY 

INTRODUCED WITH STORED FOODS. Ent. Mo. Mag. 79 (955) :275-277. 

(76) HOLDAWAY, F. G. ET AL. 

1941. ENTOMOLOGY. Rpt. Hawaii Agr. Expt. Sta. 1940:38-45. 

(77) Hooker, W. A. 

1907. the TOBACCO THRIPS, A NEW AND DESTRUCTIVE ENEMY OF SHADE- 
GROWN TOBACCO. U. S. Dept. Agr. Bur. Ent. Bul. 65, 24 pp. 

(78) Hosny, M. 

1940. ON COCCIDS FOUND ON ROOTS OF PLANTS IN EGYPT. Ministr. Agr. Egypt. 

Bul. 237 (4), 21 pp. 

(79) Howard, L. O. 

1922. report of the entomologist. 1920-21. U. S. Dept. Agr. 33 pp. 

(80) Hoyt, L. F. 

1928. fumigation tests with ethylene dichloride-carbon tetrachlo- 

RIDE MIXTURE. Ind. and Eng. Chem. 20 (5 and 9):460-461 and 
931-932. 

(81) ISELY, DWIGHT. 

1935. RELATION OF HOSTS TO ABUNDANCE OF COTTON BOLLWORM. Univ. of 

Ark. Agr. Expt. Sta. Bul. 320. 

(82) 

1929. THE SOUTHERN CORN ROOTWORM. Ark. Agr. Expt. Sta. Bul. 232, 31 pp. 

(83) Jarvis, E. 

1919. insects ATTACKING PEANUTS IN QUEENSLAND. Queen. Agr. Jour. 12 (4) : 
200-204. 

(84) Kehring, H. 

1915a. les degats des microlepidopteres dans les tourteaux d'ara- 
CHIDES. Bul. Soc. Etude Vulg.-Zool. Agr. 14 (1 and 2):l-2. 

(85) 

1915b. Ephestia elutella injuring groundnut cake in France. Mo. Bul. 
Agr. Intell. and Plant Diseases 6 (2):319-320. 

(86) Lacroix, D. S. 

1935. insect pests of growing tobacco in Connecticut. Conn. Agr. Expt. 
Sta. Bul. 379:115-117. 

(87) Lane, M. C. 

1935. recent progress in the control of wireworms. Proc. World's Grain 
Exhib. and Conf. 1933, Ottawa, 2:529-534. 



256 THE PEANUT— THE UNPREDICTABLE LEGUME 

(88) Lean, O. B. 

1930. experiments on the life history and control of the yam beetle 
IN BENNE. 8th Ann. Bui. Agr. Dept, Nigeria, pp. 43-57. 

(89) Leefmans, S. 

1927. ziekten en plagen der cultuurgewassen in nederlandsch-indie 

IN 1926 (diseases and pests of CULTIVATED PLANTS IN DUTCH EAST 

INDIES IN 1926). Meded. Inst. Plziek 73, 60 pp. 

(90) Lever, R. J. A. W. 

1941. Ann. Rpt. Div. Ent. for 1940. Suva. Dept. Agr. Fiji, 2 pp. 

(91) Livingstone, E. M. and Swank, G. R. 

1940. ACTIVITIES of THE ADULT WHITE-FRINGED BEETLE IN NEW ORLEANS 
AND VICINITY FROM SEPTEMBER 1938 TO MAY 1939. Jour. Econ. 

Ent. 33 (l):203-204. 
(92) 

1942. FUMIGATION OF SMALL LAND AREAS FOR CONTROL OF WHITE-FRINGED 

BEETLES. Jour. Econ. Ent. 35 (6):919-922. 

(93) Luginbill, Philip. 

1928. the FALL ARMY WORM. U. S. Dept. Agr. Tech. Bui. 34 

(94) AND AiNSLIE, G. G. 

1917. THE LESSER CORNSTALK BORER. U. S. Dept. Agr. Dept. Bul. 539, 27 pp. 

(95) Lyle, Clay. 

1927. the LESSER CORNSTALK BORER {Elasmopalpus Ugnosellus). Quart. Bul. 
Miss. St. PI. Bd. 7 (2):2-3. 

(96) Lyne, W. H. 

1933. REPORT OF CHIEF PLANT QUARANTINE OFFICER. Ann. Rpt. B. C. Dept. 

Agr. 27:U23-U29. 

(97) Mackie, D. B. 

1938. methyl BROMIDE — ITS EXPECTANCY AS A FUMIGANT. Jour. Econ. Ent. 

31 (l):70-79. 

(98) Marsh, H. O. 

1910. biologic notes on species of diabrotica in southern texas. u. s. 
Dept. Agr. Bur. Ent. Bul. 82 (Pt. II):76-84. 

(99) Mason, C. 

1915. report of entomologist for year ending 31 march, 1915. dept. 
Agr. Nyasaland Protectorate Zomba, 16 pp. 

(100) Merkl, Marvin E. 

1949. A STUDY OF CHEMICAL CONTROL AND LIFE HISTORY OF Heliothis armigera 
(hbn.) M. S. Degree Thesis on File Library, Ala. Poly. Inst. 

(101) Metcalf, C. L. AND Flint, W. P. 

1939. DESTRUCTIVE AND USEFUL INSECTS. McGraw-HiU Book Co. 2nd Ed. 
p. 799. 

(102) Metcalf, Z. P. 

1937. PEANUT "pouts." Science 86 (2234) :374. 

(103) Miller, D. 

1922. INSECT notes: season 1921-22. N. Z. Jour. Agr. 24 (5): 294-296. 

(104) Miller, L. I. 

1942. peanut leafspot and leafhopper control. Va. Agr. Expt. Sta. 
Bul. 338, 24 pp. 



INSECT PESTS 257 

(105) Miller, L. I. 

1943. A WHITE GRUB INJURING PEANUTS IN EASTERN VIRGINIA. Jour. EcOn. 

Ent. 36 (1):113-114. 

(106) 

1946. PEANUT LEAF-SPOT CONTROL. Va. Agr. Expt. Sta. Tech. Bui. 104, 85 pp. 

(107) Naude, T. J. 

1929. INSECT PESTS OF COTTON AND TOBACCO IN SOUTH AFRICA. Pan. Afr, 

Agr. Vet. Conf. Pretoria, pp. 225-256. 

(108) Nelson, R. H. and Weigel, C. A. 

1939. THE gladiolus thrips and ITS control. U. S. Dept. Agr. Bur. Ent. 

and Plant Quarantine. E-462, 5 pp. 

(109) Newman, L. J. 

1924. report of economic entomologist. W. Austr. Dept. Agr. Ann. Rpt., 
1923-1924. pp. 20-24. 

(110) Okuni, T. 

1928. report OF THE studies on stored grain pests, part II. (in Japanese) 
Rep. Govt. Res. Inst. Dept. Agr. Formosa 34, 121 pp. 

(111) Padget, L. J. and Littig, K. S. 

1940. THE white-fringed beetle. U. S. Dept. Agr. Bur. Ent. and Plant 

Quarantine. E-505, 13 pp. 

(112) Phillips, W. J. and Barber, G. W. 

1931. THE CORN EARWORM AS AN ENEMY OF FIELD CORN IN THE EASTERN 

STATES. U. S. Dept. Agr. Farmers Bui. 1651. 
(113) 

1933. EGG-LAYING HABITS AND FATE OF EGGS OF THE CORN EARWORM MOTH 

AND FACTORS AFFECTING THEM. Va. Agr. Expt. Sta. Tech. Bul. 47. 
(114) Poos, F. W. 

1932. BIOLOGY OF THE POTATO LEAFHOPPEti,' EmpOOSCa fabae (HARRIS), AND 

SOME CLOSELY RELATED SPECIES OF Empoosca. Jour. Econ. Ent. 
25 (3):639-646. 
(115) 

(116) 



1941. ON THE CAUSES OF PEANUT "pouTS." Jour. Econ. Ent. 34 (5):727-728. 



1945 CONTROL OF TOBACCO THRIPS ON SEEDLING PEANUTS. Jour. Econ. 

Ent. 38 (4) :446-448. 
(117) AND E. T. Batten. 

1937. GREATLY INCREASED YIELDS OF PEANUTS OBTAINED IN ATTEMPTS TO 

CONTROL POTATO LEAFHOPPER. Jour. Econ. Ent. 30 (3):561. 
(118) 



1945. DDT TO CONTROL CORN FLEA BEETLE ON SWEET CORN AND POTATO 
LEAF HOPPER ON ALFALFA AND PEANUTS. Jour. Econ. Ent. 38 (2) : 

197-199. 
(119) AND E. T. Batten. 

1948. USE OF DDT DUST MIXTURE IS NOW RECOMMENDED FOR PEANUT PESTS 

CONTROL. Peanut Jour, and Nut World. 27 (6):S2. 
(120) , J. M. Grayson and E. T. Batten. 

1947. INSECTICIDES TO CONTROL TOBACCO THRIPS AND POTATO LEAFHOPPER 

on peanuts. Jour. Econ. Ent. 40 (6) :900-905. 



258 THE PEANUT— THE UNPREDICTABLE LEGUME 

(121) POPENOE, C, H. 

1911. THE INDIAN MEAL MOTH AND "WEEVIL-CUT" PEANUTS. U. S. Dept. 

Agr. Bur. Ent. Circ. 142, 6 pp. 

(122) PuRSWELL, Henry D. 

1947. SEASONAL OCCURRENCE OF THE VELVETBEAN CATERPILLAR IN SOUTH- 
EASTERN ALABAMA, INCLUDING DATA ON LIFE HISTORY AND TOXICITY 

TESTS WITH SEVERAL ORGANIC INSECTICIDES. (Unpublished Thesis, 
Ala. Poly. Inst. Library, 21 pp., 5 plates). 

(123) PUSSARD, R. 

1939. CONTRIBUTION A L'ETUDE DES EMBIOPTERA. NOTE PRELIMINAIRE SUR 

Embia {Monotylota) ramburi rimsky. C. R. Sacssav. 71:283-289. 

(124) QUAINTANCE, A. L. AND BrUES, C. T. 

1905. THE COTTON BOLLWORM. U. S. Dept. Agr. Bur. of Ent. Bui. SO. 

(125) Ramakrishna, A. T. U. 

1929. THE ECONOMIC STATUS OF INDIAN THYSANOPTERA. Bul. Ent. RcS. 

(London) 20 (l):77-79. 

(126) Robinson, J. M. 

1939. FALL ARMY WORM. U. S. Dept. Agr. Bur. of Ent. & Plant Quarantine 
Insect Pest Survey Bul. 19:550. 

(127) 

1925. Ann. Rpt. Ala. Agr. Expt. Sta. 36:13-14. 

(128) 

1929. Ann. Rpt. Ala. Agr. Expt. Sta. 40:23. 

(129) ROEPKE, W. 

1917. VERSLAG OVER HET JAAR 1916-17. (RPT. ON THE YEAR 1916-17). 

Med. Proefstation Midden-Java 28:10-33. 

(130) 

1926. VORRATSSCHADLINGE AUF JAVA. (pests of STORED PRODUCTS IN JAVA.) 

Mitt. Ges. Vorratsschutz (Berlin) II (5):50-53. 

(131) ROUBAUD, E. 

1916. LES INSECTUS ET LA DEGENERESCENCE DES ARACHIDES AU SENEGAL. 

(insects AND THE DETERIORATION OF GROUNDNUTS IN SENEGAL.) 

L'Ann. et Mem. du Com. d'Etudes Hist, et Scien. de I'Afrique occ. 
Francaise (Sine loco). 76 pp. 

(132) Shchegolev, V. N. 

1930. pests of Archis hypogoea in north Caucasus (russia). Jour. Agr. 

Res. N. Causasus 3 (20):141-150. 

(133) Shear, G. M. and Miller, L. I. 

1941. THRIPS INJURY TO PEANUT SEEDLINGS. The Plant Disease Reporter 
25 (19):470-474. 

(134) Sheppard, R. a. 

1926. INSECT pests IMPORTED ON MISCELLANEOUS PLANT PRODUCTS. Ann. 

Rpt. Ent. Soc. Ont. 56:50-54. 

(135) Shull, a. F. 

1917. SEX DETERMINATION IN Anthothrips verbasci osb. Genetics 2:480-488. 

(136) Simmons, P., Reed, W. D. and McGregor, E. A. 

1931. fig insects in California. U. S. Dept. Agr. Circ. 157, 72 pp. 



INSECT PESTS 259 

(137) Smith, C. E. and Allen, N. 

1932. the migratory habit of the spotted cucumber beetle. jour. 
Econ. Ent. 25 (l):53-57. 

(138) Smyth, E. G. 

1918. ann. rpt. puerto rico insular expt. sta. 1917-18. pp. 109-129. 

(139) Stewart, M. A. 

1943. USE OF METHYL BROMIDE AS A FUMIGANT. Proc. Pacific Sci. Congf. 
6:153-158. 

(140) Strong, L. A. 

1922. SYNOPSIS OF WORK OF BUREAU OF PLANT QUARANTINE FOR MONTHS 

OF SEPT. TO DEC. 1921. Mo. Bill. Calif. Dept. Agr. 11 (1 and 4). 

(141) 

1940. RPT. CHIEF BUR. ENT. AND PLANT QUARANTINE FOR 1938-39. U. S. 

Dept. Agr., 117 pp. 

(142) SwAiN, R. B. 

1943. NEMATODE PARASITES OF THE WHITE-FRINGED BEETLES. Jour. EcOn. 

Ent. 36 (5):67l-673. 

(143) 

1945. THE ASSOCIATION OF NEMATODES OF THE GenUS Diplogaster WITH 

WHITE-FRINGED BEETLES. Jour. Econ. Ent. 38 (4) :488-490. 

(144) SWEETMAN, H, L. 

1926. RESULTS OF LIFE HISTORY STUDIES OF DiabroHca 12-punctata fabr. 
(CHRYSOMELIDAE, coleoptera). Jour. Econ. Ent. 19 (3):484-490. 

(145) Vayssiere, p. 

1939. au sujet de l'organisation de la lutte contre les insectes 

NUISIBLES au SENEGAL ET AU SOUDAN. Act. AsS. Col. Sci. 15 (166- 

167) :45-52, 65-70. 

(146) Vickery, R. a. 

1929. studies on the fall army worm in the gulf coast district of 
TEXAS. U. S. Dept. Agr. Tech. Bui. 138. 

(147) Wallace, C. R. 

1940. ON THE occurrence of the weevil Naupactus leucoloma boh. in 

AUSTRALIA. Jour. Aust. Inst. Agr. Sci. 6 (4):209-211. 

(148) Watson, J. R. 

1916. LIFE HISTORY OF THE VELVETBEAN CATERPILLAR {Atiticarsia gemmatiUs 
hubner). Jour. Econ. Ent. 9 (6):521-528. 
(149) 



1918. Report of the Department of Entomology, Fla. Agr. Expt. Sta. Rpt. 
for Fiscal Year Ending 30th June 1917. 



(ISO) 
(151) 

(152) 
(153) 



1918. THYSANOPTERA OF'FLORIDA. Florida Buggist 1 (4) and 2 (1): 53-77. 



1922a. REPORT OF ENTOMOLOGIST. Fla. Agr. Expt. Sta. Rpt. 1921-1922. 
pp. 56-59. 



1922b. THE FLOWER THRIPS. Fla. .'Vgr. Expt. Sta. Bui. 162:27-51. 



1930. Report of the Department of Entomology, Fla. Agr. Expt. Sta. Rpt. 
for Fiscal Year Ending June 30, 1930. p. 67. 



« 

260 THE PEANUT— THE UNPREDICTABLE LEGUME 

(154) Watson, J. R. 

1937a. Naupactui leucoloma (coleoptera, curculionidae), a pest new 
TO the united states. Fla. Ent. 20 (l):l-3. 

(155) . 

1937b. additional notes on naufactus leucoloma. Fla. Ent. 20 (2): 
22-25. 

(156) Watts, J. G. 

1934. A COMPARISON OF THE LIFE CYCLES OF FrankUtiiella tritica (fitch), 
F.fusca (hinds) and Thrips tabaci lind. (thysanoptera-thripidae) 
IN south CAROLINA. Jour. Econ. Ent. 27 (6): 1158-1159. 

(157) 

1936. A SURVEY OF THE BIOLOGY OF THE FLOWER THRIPS FrankUniella tritici 

(fitch) with SPECIAL REFERENCE TO COTTON. S. C. Agr. Expt. Sta. 

Bui. 306, 46 pp. 

(158) 

1938. SPECIES OF thrips found on cotton in south CAROLINA. Jour. Econ. 
Ent. 30 (6) :857-860. 

(159) Weiss, H. B. 

1918. the control of imported pests RECENTLY FOUND IN NEW JERSEY. 

Jour. Econ. Ent. 11 (1):122-12S. 

(160) Wilson, Coyt and Arant, F. S. 

1949. CONTROL of insects AND DISEASES OF PEANUTS. Ala. Agr. Expt. Sta. 
Leaflet 27. 

(161) Wilson, J. P. and Arant, F. S. 

1947. STATUS OF peanut-worm control. Ala. Agr. Expt. Sta. Mimeogr. 
Leaflet. 

(162) Winburn, T. F. and Painter, R. H. 

1932. insect enemies of the corn earworm. Jour. Kan. Ent. Soc. 5 (1). 

(163) WiSECUP, C. B. and Hayslip, N. C. 

1943. control of mole crickets by use of poisoned baits. U. S. Dept. 

Agr. Leaflet 237, 6 pp. 

(164) Woodroof, J. G., Thompson, Helen H. and Cecil, S. R. 

1947. refrigeration of peanuts and peanut products. Refrigerating 
Engineering 53 (2):124. 

(165) Young, H. C. 

1944. DDT against the white-fringed beetle and velvetbean cater- 

pillar. Jour. Econ. Ent. 37 (1);145-147. 

(166) 

1945. insectory and field-cage tests with DDT against white-fringed 

BEETLE ADULTS CONDUCTED AT FLORALA, ALABAMA, DURING 1944. 

U. S. Dept. Agr. Bur. Ent. and Plant Quarantine. E-662, 4 pp. 
(167) 



(168) 



1946. Ann. Prog. Rpt. Florala, Ala., White-Fringed Beetle Sta. U. S. Dept. 
Agr. Bur. Ent. and Plant Quarantine in Coop, with State Agencies 
of Fla., Miss., Ala. and La. 



1947. Ann. Prog. Rpt. Florala, Ala., White-Fringed Beetle Sta. U. S. Dept. 
Agr. Bur. Ent. and Plant Quarantine in Coop, with State Agencies 
of Fla., Miss., Ala. and La. 



INSECT PESTS 261 

(169) Young, H. C. and App, B. A. 

1939. BIOLOGY OF THE WHITE-FRINGED BEETLE NaUpactUS LeUColoma BOH. 

U. S. Dept. Agr. Bur. Ent. and Plant Quarantine E-464. 

(170) AND Green, G. D. 

1938. THE WHITE-FRINGED BEETLE, Naupactus leucoloma BOH. U. S. Dept. 
Agr. Bur. Ent. and Plant Quarantine. E-420, 14 pp. 

(171) AND Gill, J. B. 

1948. soil TREATMENTS WITH DDT TO CONTROL THE WHITE-FRINGED BEETLE. 

U. S. Dept. Agr. Bur. of Ent. and Plant Quarantine. E-750. 

(172) Zacher, F. 

1929. EIN fur DEUTSCHI.AND NEUER SCHLADING AN BACKOBST CarpOpMlus 

ligneus murr, und andere saftkafer ; C. ligneus, a pest of dried 

FRUIT NEW TO GERMANY AND OTHER NITIDULID BEETLES. Mitt. Ges. 

Vorratsschutz 5 (l):2-5. 

(173) 

1932. INTERESSANTE FAELLE DES SCHADLINGSAUFTRETENS AN NAHRUNGSUND 

genussmitteln, webwaren UND BAUSTOFFEN. Mitt. Ges. Vor- 
ratsschutz 8 (4) :42-48. 



CHAPTER VIII 



PEANUT DISEASES 



By 



KENNETH H. GARREN^ AND COYT WILSON^ 



In the early years of its cultivation, the peanut was considered some- 
what disease resistant. In 1895, after peanuts had been an important crop 
for a half century, a bulletin (55) on peanuts, published by the U. S. 
Department of Agriculture, made no specific mention of diseases. Re- 
visions of this bulletin, dated 1909 and 1917, described peanuts as re- 
markably free from disease. Leafspot was mentioned but damage was 
regarded as unimportant except in low or poorly drained portions of 
fields (15, 16). 

As peanut production increased, diseases began to attract more at- 
tention. There began, therefore, an Era of Exploration. During this 
period numerous peanut diseases were observed and recorded, many of 
which never appeared again in the literature. The next era was notable 
for concentrated study of a few diseases of outstanding local importance. 
Among such diseases were: Bacterial wilt in the East Indies, rosette in 
Africa, and leafspot in the southern United States. Overlapping this 
Concentrated Era was a fourth or General Era which resulted in the 
publication of reviews of peanut diseases, either from a world-wide (86) 
or strictly localized viewpoint (64, 98, 99). 

At the present time interest in and the study of peanut diseases appear 
to be in this general phase. During the years 1941 to 1945 the acute 
shortage of vegetable oils focused attention on peanut culture in the 
United States and numerous surveys of peanut diseases were made. As a 
result of these surveys there developed the concept that many diseases 
other than the obvious ones are found in peanut fields, and that, while the 
damage caused may be considerable (125), it is difficult to estimate the 
specific damage to be attributed to individual diseases. 

^ Kenneth H. Garren, formerly associate botanist, Geor8:ia Agricultural Experiment Station, 
is associate professor of botany and plant pathology, Alabama Polytechnic Institute; Coyt Wilson 
is plant pathologist at the same institution. 

262 



peanut diseases 263 

Peanut Diseases of Major Importance 
IN THE United States 

DISEASES AFFECTING STAND ESTABLISHMENT 

Spotty stands of peanuts are common in the southeastern United 
States (124) and other peanut-producing regions (43, 64). Since pro- 
duction costs per ton are largely a function of area cultivated, these poor 
stands are important considerations in the economics of peanut produc- 
tion. 

Several things may account for spotty stands. The principal causes 
appear to be: (A) Poor seed stocks (old seeds, improperly stored seeds, 
seeds with fungus damage or mechanical injury, etc.). (B) Over-stretch- 
ing of seed supply or improper spacing of seeds. (C) Inferior planting 
equipment. (D) Unfavorable conditions after planting. (E) Depreda- 
tions of field mice, birds, and other animals. (F) Seed rots and seedling 
blights. 

Consideration of these items shows that disease is not the sole 
factor causing poor stands. 

A number of distinct diseases affect peanuts early in the growing 
season. When considered individually, many of these diseases do not ap- 
pear to be of importance. Collectively, however, they often are serious. 
Of these, the pre-emergence diseases probably have the most direct effect 
on stand establishment in the southeastern United States (163). 

Pre-Emergence Diseases 

Importance. Soil rot of seeds is regarded as one of the three most im- 
portant peanut diseases in Rhodesia (64). Its importance in the southern 
United States must be obtained indirectly, primarily from the einphasis 
placed on control programs in recent years. The most concrete evidence 
may be obtained from reports of increased emergence of 15, 25 or up to 
40 percent following such control programs (43, 45, 46, 103). 

Description. Planted seeds and very young plants are subject to two 
types of diseases before emergence. The entire seed may be decayed, or 
the developing embryo of young plant may be attacked by saprophytic 
fungi, or damping-off fungi. Both of these types of pre-emergence dis- 
eases have been reported on peanuts (43, 102, 105). 

Organisms. The organisms associated with pre-emergence diseases 
have not been studied extensively. Soil-borne parasitic and saprophytic 
fungi may decay seeds, particularly if germination is delayed or if the seed 



264 



THE PEANUT— THE UNPREDICTABLE LEGUME 



is damaged. In addition to these soil fungi a fungus flora becomes associ- 
ated with the peanut fruit as it develops in the soil (162), is present at 
harvesting (48, 114), and is still present in or on fruits and seeds after 
storage (41,67, 111, 149). The majority of species of this fungus flora are 
saprophytes such as Aspergillus spp., Rhizopus spp., Penicillium spp., 
and Fusaria, but some are definitely parasites such as Pythium spp. 
(Ill), Sclerotium rolfsii Sacc. (149), and parasitic Fusaria (41). 

Control. Losses from pre-emergence diseases of peanuts may be sig- 
nificantly reduced by seed treatments (45, 46, 51, 64, 103, 105, 155), 
though in a few instances seed treatment for peanuts has not been con- 
sidered worthwhile (67, 76, 151). Properly applied seed fungicides will 
be effective against seed-borne saprophytes and parasites, and if germina- 
tion is not unduly delayed by adverse weather conditions these fungicides 
will also be efifective against soil-borne fungi ( 105) . Most of the beneficial 
results of seed treatment of peanuts is due to prevention of decay prior 
to germination (102, 163). 

Increases in emergences from machine-shelled seeds of 25 percent or 
more are not unusual following seed treatment, and it has been estimated 
that North Carolina farmers save around $125,000 annually by using 
treated machine-shelled seeds in preference to hand-shelled seeds (103). 
Table 1 gives some comparative emergences for treated and untreated 
machine-shelled seeds as selected from various reports. 

There are several factors that vary the effectiveness of peanut seed 
treatment. The most important of these factors are: 

Table 1. — Results of Seed Treatment Tests on Peanuts 



Location 
of test 


Type of 
seed used 


Year 
of test 


Emergence from 
Machine-shelled seeds 


Bibliog- 
raphy 
reference 


Untreated 


Treated 




Runner 

Runner 

Va. Bunch 

Spanish 

Runner 

Jumbo 

Spanish 

Spanish 

Spanish 

Runner 

Runner 

Spanish 

Spanish 


'43 

'46 

'42 

'42 

'45 

'46 

'45 

'46 

'45 

'46 
4 yr. ave. 

'46 
4 yr. ave. 


Percent 


Percent 




North Carolina 

North Carolina 

North Carolina 

North Carolina 


54 
SO 
39 
57 
66 
85 
77 
54 
53 
45 
54 
43 
SO 


75 
60-70 

61 

72 

84 

96 

94 

85 

80 

95 
73-88 

69 

79 


(105) 
(46) 

(124) 

(124) 
(45) 
(46) 
(45) 
(46) 
(45) 
(46) 

(163) 
(46) 

(163) 


Virginia 


South Carolina 

South Carolina 

Georgia 




Alabama 


Alabama 







PEANUT DISEASES 265 

(a) Type and quality of seed stocks: No amount of seed treatment 
will change poor seed into good seed. Although not recommended, "pegs" 
(shriveled, under-developed seeds) are still widely used as seed stocks. 
The comparative effectiveness of seed treatment on plump and shriveled 
seeds has been studied (46), and the results indicate that emergence 
from plump seeds is always considerably higher than that from shriveled 
seeds. When seeds are stored under conditions detrimental to quality, 
any subsequent seed treatment will be less effective. Seed treatment, 
therefore, is not a corrective for improper storage. 

(b) The use of unshelled seed. Usually there is no appreciable in- 
crease in emergence as a result of treatment of unshelled seeds (103, 124, 
155, 163). Pre-soaking Spanish peanut pods in water increases the sub- 
sequent germination of unshelled seeds (67, 103, 124), but treatment of 
pre-soaked pods gives no additional increase in germination (103). 
Germination of pre-soaked unshelled Spanish peanut seeds usually is 
less than that of treated- machine- or hand-shelled seeds (103). 

(c) Method of shelling. Injury by machine-shelling provides points 
of entry for soil fungi, and emergence from untreated hand-shelled seeds 
is much better than that from untreated machine-shelled seeds. Treating 
hand-shelled seeds generally increases emergence, but the proportion 
of increase is not as great as from treatment of machine-shelled seeds. 
Emergences from treated machine-shelled seeds compare favorably with 
emergences from untreated hand-shelled seeds (50, 105, 163). 

(d) Material used. The most apparent factor which can influence the 
effectiveness of seed treatment is the chemical itself. Numerous fungicides 
are designed exclusively for seed treatment. Three of these fungicides, 
Arasan (50 percent tetramethyl thiuramdisulfide) , 2 percent Ceresan 
(2 percent ethyl mercury chloride), and Spergon (98 percent tetrachloro- 
parabenzoquinone) , have been tested so frequently that their effectiveness 
is definitely established. The majority of reports show Arasan and 2 per- 
cent Ceresan about equal, with Spergon less effective but still very benefi- 
cial (45, 46, 50, 51, 53, 153, 155, 163, 167). Other newly introduced seed 
fungicides have been tested and some give excellent promise. Extensive 
testing should soon give definite evaluations for these newer seed fungi- 
cides. 

(e) Methods. The method of applying seed fungicides influences 
effectiveness of the treatment. A light film of the material on every seed 
is desired. Higher rates of application do not give additional increases in 
emergence (103), and over-dosage with mecurial treatments results in 
abnormal germination and seedling death (67, 163). There are, un- 



266 THE PEANUT— THE UNPREDICTABLE LEGUME 

doubtedly, many cases of apparent ineffectiveness of seed treatment due 
to poor application of the material used. Slurry treatments have not come 
into use on peanuts. 

(f) Times of shelling, treatment and planting. Peanuts shelled and 
treated up to 3 months or longer before planting produce stands as good 
as those produced by seeds shelled and treated immediately before plant- 
ing (51, 103, 163). It appears, therefore, that within reasonable limits 
the time elapsing between shelling and treatment and subsequent planting 
does not alter the effectiveness of seed treatment if the seeds are properly 
stored throughout. Treatments are equally effective if applied at the time 
of shelling or just before planting. 

(g) Environmental conditions after planting. Most of the benefits of 
seed treatment for peanuts appear to arise from prevention of decay of 
seeds prior to germination (102, 163). Rains which wash off chemicals 
before germination will decrease the effectiveness of seed treatment (67) . 
Even in comparatively dry soil there will be a gradual dissipation of the 
chemicals, thus any environmental condition inhibiting or slowing down 
germination will reduce the effectiveness of treatment. 

To summarize: The existing evidence shows that pre-emergence 
diseases of peanuts are effectively controlled by seed treatment. Factors 
which influence the effectiveness of seed treatment, however, make the 
following precautions necessary : 

1. Use only high quality seeds which have been stored properly. 

2. Use machine-shelled seeds in preference to unshelled seeds. 

3. Use a recommended seed fungicide. 

4. Follow directions for treatment and avoid injury from over-treat- 
ment or failure from under-treatment. 

5. Apply chemicals to seeds in a manner which gives even coating of 
every seed. 

6. Choose the most convenient time for shelling and treatment, but 
keep within reasonable limits. 

7. Consider environmental conditions and try to plant under con- 
ditions promoting rapid germination. 

Post-Emergence Damping-Off 

Importance. Typical damping-off causes slight losses every season in 
the southeastern United States. There are, however, no reports of damp- 
ing-off as an important disease in any peanut-producing region. Reports 
of surveys of peanut fields for diseases contain only occasional references 



PEANUT DISEASES 267 

to typical damping-off fungi. When such fungi are mentioned they are 
given a relatively minor position (97, 123). 

Control. Damping-off must be regarded as a minor factor contributing 
to poor stands of peanuts. The use of treated seeds and close spacing to 
insure replacements for plants killed by damping-off constitute the only 
recommended control measures at present. The general prevalence of 
such practices probably accounts for the inf requency with which damping- 
off is observed. 

Seedling Dry Rots 

Importance. Young peanut seedlings are subject to a type of rot 
distinct from damping-off and known as "dry rot" (63). The fungi ap- 
parently associated with most seedling dry rots in southeastern United 
States a,re Sclerotium bataticola Taub. (the "charcoal rot" organism) 
and Rhizoctonia solani Kuhn. Reports on peanut diseases have shown that 
these fungi are widespread in the United States {77, 78, 87, 101, 111, 
119, 123, 126, 157) and elsewhere (26, 115, 147, 152). In North Caro- 
lina each of these organisms accounted for about 35 percent of the total 
isolations from diseased peanut tissue (101). S. bataticola has been called 
"a major pathological and economic problem" on various crops including 
peanuts in southern United States (63), and reports on peanuts from 
India (147, 152) and Palestine (115) have similarly evaluated this 
organism. There are possibly other types of seedling dry rots as yet not 
recognized as distinct. For example, an early stage of Fusarium wilt^ 
reported from the southeastern United States (74, 92) and other regions 
(80, 115) may sometimes be confused with seedling dry rots. 

Most reports do not distinguish between seedling dry rots and the 
attacks of the same causal organisms on more mature plants. It has been 
noted that 5". bataticola attacks peanuts principally in the seedling stage 
(63, 152) but some observations may have been of the "ashy stem blight" 
on mature plants.^ Observations in southeastern United States tend to 
indicate that R. solani rarely infects mature peanut plants^ and then 
generally affects only single branches, but some of these reports may 
have included attacks on mature plants. On this basis, therefore, seedling 
dry rots are best regarded as of intermediate importance in relation to de- 
velopment of peanut stands. 

Description. Charcoal rot is easily recognized. The first symptoms 
are greenish-grey watery necrotic areas on stems just at the soil surface. 

2 See page 303 for discussion of Fusarium wilt. 

' See page 305 for discussion of "ashy stem blight," and R. solani on mature peanut plants. 



268 THE PEANUT— THE UNPREDICTABLE LEGUME 

As the water-soaked appearance disappears the necrotic areas become 
a dull, dry brown due to formation of sclerotia of S. bataticola. As lesions 
develop the number of sclerotia increases and the base of the stem looks 
very much like charcoal. Rarely does the water-soaked appearance persist 
to the charcoal stage. Usually the entire plant wilts and dies but numerous 
instances of complete recovery from charcoal rot have been observed. 
When the lesion remains small, the plant is somewhat stunted and the 
stem is easily broken by wind or cultivation. The necrotic areas and 
lesions usually extend below the soil surface for a considerable distance. 

Rhizoctonia dry rot of peanut seedlings is typical of the effects of this 
organism on plants. The first evidence is usually a faint yellowish streak 
on the stem at the soil line. This streak enlarges, becomes necrotic, and 
develops into a definite light-brown, dry crack-like lesion. When infection 
spreads around the succulent stem the top wilts and dies. Sometimes the 
unwilted tops break off at the lesions. The lesions usually do not extend 
very far below the soil line. Peanut plants frequently survive seedling in- 
fection by R. solani. 

Organisms and pathogenicity. The parasitism of Sclerotium bataticola 
has been studied with a number of plants. As once summarized (63) it 
appears that 5". bataticola is "moderately and variably aggressive. Its in- 
vasion is favored by devitalization, characteristic of plants subjected 
to environmental extremes of continental climates, and wounds or attacks 
of other organisms. It is adapted to high temperatures." Inoculation tests 
show that S. bataticola can infect and kill peanut seedlings at fairly high 
temperatures but not at low temperatures (111). 

The parasitism of R. solani has been established by studies on many 
crop plants. Inoculation tests show that R. solani produces dry-rot of 
peanut seedlings identical with that found in the field. R. solani grows 
readily from field dry-rotted peanut seedlings in moist chambers though 
it is sometimes difficult to obtain the organism by the usual methods of 
isolation. 

Although differences in susceptibility of peanuts to infection by R. 
solani have been reported (147), no resistant varieties have been sug- 
gested. Twenty peanut varieties have been tested for susceptibility to 
5. bataticola and no resistance was noted though peanuts grown under 
irrigation and shallow cultivation were attacked more frequently than 
those grown in dry soil with deep cultivation (147). 

Control. Both 5". bataticola and R. solani can be seedborne (41, 48, 
147) . A high percentage of infection by R. solani is sometimes attributed 
to seed-borne inoculum (147), but it probably is less frequently seed- 



PEANUT DISEASES 269 

borne than is 6". bataticola. Seed treatment should be effective against 
most of the seed-borne inoculum. Since these organisms are universally 
established in peanut soils, seed-borne inoculum may be a minor source 
of infection. Seed treatment may be effective against a considerable por- 
tion of the soil-borne inoculum, particularly in the case of S. bataticola, 
which frequently infects seedlings through cotyledons. Close spacing of 
seeds to insure replacements is also to be recommended. 

Collar Rot* 

Importance. In the southeastern United States peanuts are subject 
to a stem and root rot which developed later than damping-off and seed- 
ling dry-rots, and features otherwise distinct. The name "collar rot" is 
proposed for this disease. Apparently such rots have been noted in the 
southeastern United States for some time (97, 101, 111) and previous 
reports have indicated that the problem is a complex one (101, 111). 

Collar rot was serious in several Georgia counties in 1946 and 1947. 
In 1946 the entire stand was so depleted in a 10-acre field that replanting 
was necessary. A similar situation was reported from Texas in 1941 
(74). Serious depletions of experimental stands were observed in 1947 in 
Georgia, and depletions of farmers' fields of runner peanuts were noted 
in Alabama in 1947 and 1948^. A few references in the literature indi- 
cate, indirectly, that an early root-rot disease is prevalent in other States 
(74, 101, 111, 123) and the crown rot of peanuts described from Aus- 
tralia (99, 100) bears many points of resemblance to collar rot. 

Description. Peanuts succumb to collar rot from emergence to early 
flowering. The disease, however, seems most prevalent from 20 to 40 
days after planting. When plants are attacked shortly after emergence, 
hypocotyls are killed and there are black necrotic areas on cotyledons 
and plumules. In early stages the main axis of plants are wilted with 
necrotic areas in the region of the cotyledons, but side branches and root 
systems are unaffected. Frequently a good mat of adventitious roots has 
been formed just below the cotyledons. Next, the main axis dies and the 
necrosis spreads downward on the taproot. A few plants recover even 
after the main axis is dead and the taproot badly rotted. Undoubtedly this 
recovery is due to good development of adventitious roots. The majority 
of plants attacked, however, either die or remain stunted. The advanced 
stage is characterized by dead taproot systems and side branches dying or 

* Based primarily on observations made in Georgia and on unpublished data of the Georgia Ex- 
perintent Station. 

° Observations from unpublished data of the co-author, Coyt Wilson, Alabama Experiment 
Station. 



270 THE PEANUT— THE UNPREDICTABLE LEGUME 

Table 2. — Fungi Isolated from Peanuts with Collar Rot in Georgia, 1945-1947^ 



Fungus isolated 

Fusarium spp 

Diplodia sp 

Pemcillium spp 

Aspergillus spp 

Rhizopus sp 

Sclerotium bataticola 

Rhizoctonia solani 

Trichoderma spp 

Bacteria 



Comparative frequency 



Frequent 

Frequent 

Fairly frequent 

Fairly frequent 

Fairly frequent 

Fairly frequent 

Rare 

Rare 

Rare 



living only when some adventitious roots have developed. In this stage, 
the main axis and taproot are shredded and held together by a few sound 
vascular bundles. The mass of dead tissue is usually dark reddish brown 
and powdery. 

Organisms and pathogenicity. The nature of early collar rot suggests 
a fungous disease, and no evidence has been obtained which would con- 
nect insects or grubs directly with the disease. Somewhat detailed isola- 
tions of fungi from diseased plants have been made, and typically, a 
variety of fungi was isolated with no agreement between seasons as to the 
predominant fungus. Table 2 lists the comparative frequency of isolation 
of several fungi from diseased plants in Georgia. 

Similar results have been reported from North Carolina (101, 111). 

Since a number of these fungi have been reported as pathogens on pea- 
nuts (table 3), inoculation tests were run for 3 years at the Georgia Ex- 



Table 3.- 



-FuNGi Ordinarily Considered Saprophytes Reported as Pathogenic 
FOR Peanuts 



Fungus 


Reported from 


Patho- 
genicity 
tested 


Patho- 
genicity 
proved 


Bibliog- 
raphy 
reference 


Diplodia sp 


Southeastern United States 
Southeastern United States 
Southwestern United States 
Burma 


No 
Yes 

No 


No 


(119) 
(149) 


Penicillium spp. . . . 


Uganda 


— 


— 


(145) 


Aspergillus sp 


East Indies 
Australia 


Yes 


Yes. ,, 


(72) 
(99, 100) 


Rhizopus sp 


Uganda 


— 


— 


(145) 



' Unpublished data, Georgia Experiment Station. 



PEANUT DISEASES 271 

periment Station, with fresh isolations of all fungi from collar-rotted pea- 
nuts. In two tests one set of plants was wounded by tearing off cotyledons 
and ripping through stems underneath the soil surface. 

With the exception of R. solani there was no indication of patlio- 
genicity for any fungi or bacteria. Even the severely wounded plants de- 
veloped to maturity after inoculation. Most plants inoculated with R. 
solani died, but the necrosis was typical for R. solani infection and in no 
way resembled collar rot as observed in the field. In 1948 with isolates of 
fungi from collar rot of runner peanuts Wilson'' found some indication of 
parasitism for Diplodia sp. 

From inoculation tests no specific fungus can at present be connected 
with collar rot of peanuts. There are, however, several possible explana- 
tions for the disease, the most likely of which are: (A) The disease is 
due to a fuiigus not yet isolated and identified; (B) the disease is due 
either to R. solani, a parasitic Fusarium sp., or to a parasitic bacterium 
and the true pathogen is obscured by a succession of saprophytic fungi ; 
or (C) an involved complex operates in peanut fields in which mechanical 
injury, chemical injury, insect and nematode injury, and "light" parasitic 
infection all provide dead tissue in which ordinarily saprophytic fungi 
thrive and eventually destroy living tissue. A similar complex has been 
suggested as associated with a root rot of tobacco and small grains (70), 
and it has been indicated that peanut root rot may, under different con- 
ditions, result from a wide variety of fungi (111). 

Control. Collar rot has been observed as frequently and to as great an 
extent in fields planted with treated seeds as in those planted with un- 
treated seeds. There have been instances in which injury from seed treat- 
ment has been suspected as a factor in the development of the disease. At 
present the only recommendations for control are : ( A) Use of seed stocks 
carefully selected to eliminate damaged or broken seeds; (B) use of care 
in treatment of seeds to avoid injury from seed treatment; (C) close 
spacing of seeds to insure good stands even if some plants are killed by 
collar rot. 

DISEASES OF THE GROWING SEASON 

Cercospora Leajspot 

Importance. Because of frequency of occurrence Cercospora leafspot 
is generally regarded as one of the most important diseases, or perhaps 
the most important disease of peanuts. Although it has received more at- 

' Unpublished data, Alabama Experiment Station. 



272 THE PEANUT— THE UNPREDICTABLE LEGUME 

tention than any other disease of peanuts in the United States, there is 
Httle agreement as to its relative destructiveness. 

Obviously the defoliation greatly decreases the value of the vines for 
hay, but as indicated by Miller (94) there are observers who feel that 
leafspot does not result in appreciable reduction in yield of nuts. The 
majority of observers, however, maintain that considerable loss in yield 
of nuts results from the disease. 

The best estimate of importance of peanut leafspot may be obtained 
from results of studies on control. In Virginia 30 tests showed average 
yields about 500 pounds per acre less in untreated fields than in fields in 
which leafspot had been decreased by control measures (94). This indi- 
cated a loss in yield of about 20 percent from leaf-spot infection. Interpret- 
ing results of extensive tests in Georgia similarly (172) the nut-yield 
loss from leafspot is indicated as from 20 to 25 percent. 

Description. Two fairly distinct types of necrotic spotting are recog- 
nized as common on peanuts in the southeastern United States, and each 
has been connected with a specific Cercospora sp. (68, 171). The exist- 
ence of two species of Cercospora associated with peanut leafspot was 
clarified by Woodroof in 1932 (171). The eflfects produced by these 
organisms, however, are still regarded as only one disease. Control 
measures seem equally effective on both organisms. Peanut-breeding 
programs, however, may produce varieties resistant to only one of the 
pathogens (61), in which case it may be necessary to divide "peanut 
leafspot" into two diseases. 

Spotting associated with Cercospora arachidicola Hori {Mycosphae- 
rella arachidicola Jenkins) appears earlier and becomes epiphytotic 
earlier than does that associated with C. personata (B. and C.) E. and 
E. {M. berkeleyii Jenkins). It seems logical, therefore, to designate them 
"early leafspot" and "late leafspot." There is a period of overlapping, 
however, and frequently both types of spotting are found on the same 
plant (171). 

In the initial stages the two types of spotting are indistinguishable 
(68). Spots appear as slightly pale or blanched-like areas and a break- 
down of the lower epidermis is evident. The spots develop rapidly and 
become distinctly yellow on the upper surface of the leaflet. With this a 
necrosis develops from the center of the lesion, or the entire lesion may 
become necrotic at one time. 

Later stages in necrosis serve to distinguish between the two leaf- 
spots (68). Early leafspot is characterized by a yellow halo of variable 
width, while halos are found only with more mature spots of the late type. 



PEANUT DISEASES 



273 



At maturity early leafspots are reddish-brown to black, and lighter brown 
to tan with less distinct halos on the lower surface. Late leafspots are 
soon very dark brown to almost black on both surfaces. 

Cushions of conidiophores are formed at first only on the upper sur- 
face in early leafspot, but sometimes form on the lower surfaces of older 
spots. In late leafspot, however, conidiophores are almost always confined 
to the lower leaf surfaces, and the cushions of tufts usually are in plainly 
visible concentric circles. When the conidiophore cushion of late leafspot 
becomes amphigenous with age, this concentric marking remains plainly 
evident (68). 

Both leafspots are distinctly necrotic at maturity. The spots are 
circular, or irregular, and often coalescing. Sizes range from 1 mm. to 
over 1 cm. in diameter (68). Spots on stems, petioles, pegs and pods are 
similar, but more frequently are irregular or eliptical in shape. In early 
leafspot the petioles and stem lesions develop later in the season than do 
those on the leaves (171). These symptoms are shown in figure 1. 

Apparently control measures so effectively prevent premature leaf 
shedding (68, 171) that few observations have been made on defoliation 










r*.. 






Courtesy Alabama Agricultural Experiment Station. 

Figure 1. Cercospora leafspot on leaves of runner peanuts. The spots with the 

halos on the leaf at the left are old lesions caused by Cercospora arachidicola. 
The dark spots on the leaf at the right are young lesions caused by Cercospora 
personata. 



274 THE PEANUT— THE UNPREDICTABLE LEGUME 

eflfects. The interrelationships between time of infection, severity of in- 
fection, beginning of defoliation, and severity of defoliation have not been 
extensively studied. In Georgia, leafspot appears sometimes in June on 
peanuts planted in late April (172), and without control spotting in- 
creases rapidly during July so that defoliation is noticeable by August. A 
close relationship is observed to exist between the amount of leaf spotting 
and the amount of defoliation (94). 

Comparative studies (68, 171) have shown that late leafspot usually 
appears 3 to 4 weeks later than early leafspot. 

Organisms and pathogenicity. Woodroof (171) has clarified the 
synonomy and nomenclature of the conidial stages of the peanut leafspot 
organism. Her studies established Cercospora arachidicola Hori as the 
correct name for the early leaf-spot organism, and C. personata (B. and 
C. ) E. and E. as the correct nanie for the late leafspot organism. Jenkins 
(68) studied the development of both organisms and connected them 
with Mycosphaerella perithecial stages which were found to develop only 
on overwintered material. 

The pathogenicity of both organisms has been proven (68). The first 
infection is from ascospores formed on overwintered peanut debris. 
There have been reports that the disease is seed-borne (94) but most ob- 
servers feel that it is not. Following initial infection and an "incubation" 
of 2 to 3 weeks (68) the lesions become evident and the organisms pro- 
duce conidia in abundance. These conidia then spread infection rapidly. 

There is a leafspot of the common coflfee weed {Cassia tor a L.) of 
the southeastern United States caused by a Cercospora sp., but attempts 
at cross inoculation of this Cercospora sp. with peanuts have failed^. 
Possibly other weeds are hosts of the peanut leaf-spot organism and thus 
may serve as additional sources of ascospores for initial infection. As a 
rule, however, there is more than enough peanut debris to provide an 
abundance of initial inoculum. 

The production of perithecia of the organisms on overwintering ma- 
terial has been studied (68). It appears that even under ideal conditions 
perithecia are formed sparingly. Rapid disintegration of the substratum 
may be a factor in this, and temperature may be a limiting factor since 
mature perithecia are not found in Georgia before June. Some rainfall 
during the period of spermagonial discharge is also necessary. Asci al- 
most always mature gradually so that ascospores are discharged over a 
considerable period of time. Initial infections usually are scattered in the 
southeastern United States (68), but peanut fields rarely, if ever, escape 

s Unpublished results, Georgia Experiment Station. 



PEANUT DISEASES 275 ■ 

infection. Small spots of initial infection serve as the starting point from 
which secondary infection spreads over almost unlimited areas. 

Conidia are primarily windborne (94) and other means of dissemi- 
nation are of little significance. Under ideal conditions conidia germinate 
within 3 to 8 hours (68) , The conidia do not germinate if completely cov- 
ered by water, or if there is insufficient moisture. Infection takes place 
through either surface of the leaflet, but most infection probably is 
through the lower surfaces since they are not subject to rapid dessication. 

Penetration of the germ tube is through epidermis or stomata. Cer- 
cospora arachidicola has intercellular mycelium but no haustoria. Host 
cells die rapidly in advance of the mycelium, and the hyphae penetrate 
the dead cells. Mycelium of Cercospora personata leafspot organism re- 
mains intercellular with branched or botryose haustoria which may be 
found in apparently normal cells. 

The early leaf-spot organism develops consistently but the late leaf- 
spot organism is sporadic, being widespread some years, and again rarely 
found or entirely missing. It appears that, when occurring, the late leaf- 
spot organism causes a more rapid defoliation (68, 171). The regular 
occurrence of early leafspot and harvesting of many peanuts before late 
leafspot reaches epiphytotic proportions indicate that in lower southeast- 
ern United States early leafspot is more destructive. In this region early 
leafspot usually becomes epiphytotic in August ; late leafspot sometime in 
September (68). 

Factors influencing the severity and spread of infection by leaf-spot 
organism have been studied and discussed (94). Various fertilizer pro- 
grams have no apparent efifect on the disease. Age of plants, rate of early 
growth, method of weed control, and frequency of rainfall appear to be 
influencing factors. Infection is usually more severe on peanuts following 
peanuts every year or every other year than when 3-year rotations are 
practiced. 

Control. Field sanitation can offer no great hope for control of peanut 
leafspot. Resistance has been reported sporadically, but at present no 
definite resistance exists in any standard variety of peanuts. The possi- 
bilities along this line have been discussed by Higgins (61, 62) who noted 
an apparently independent inheritance of resistance to the two types of 
leaf spotting. Recently, Miller has reported the existence of physiological 
races within each species (93) which may complicate breeding programs. 
Resistant varieties may result from some of the current breeding pro- 
grams, but present-day control measures must center in preventing 
spread of infection. 



■116 THE PEANUT— THE UNPREDICTABLE LEGUME 

As shown by studies in Georgia (172), the most logical means of pre- 
venting spread of infection, is the application of fungicides which kill 
conidia on leaflets before they germinate and penetrate leaf tissue. Tests 
in Virginia (94) have indicated that plants so protected lose a lower 
percentage of nuts in the soil before digging, lose a lower percentage of 
nuts at digging, and have a greater total yield. Similar results, particu- 
larly in regard to total yield, have been obtained in Alabama (165). 

Results suggesting that fungicidal applications sometimes influence 
the number of nuts left on the vine rather than total yield have been ob- 
tained in Florida. When the nuts left in the soil were added to the har- 
vested yield there was no appreciable difference in total yields between 
control and check plots (20). However, this pubHcation cited the unpub- 
lished results of other control tests in Florida carried on over a period of 
5 years and these other tests indicated a 1 5 to 20 percent increase in yield 
of harvested nuts. Also, the weather of the particular year in which these 
experiments were made was conducive to leafspot so that no correlation 
was evident between treatment and leaf-spot control. 

Various fungicides have been tested as dusts and sprays (94, 165, 
172). Pending further testing of newer fungicides it seems that either 
sulfur or 10-90 copper-sulfur with the mixture containing the equivalent 
of about 3.5 percent metallic copper are to be recommended as dusting 
materials. Spraying with Bordeaux (6-2-100) gives satisfactory control 
but is no better than dusting. 

The following general recommendations for procedure in dusting for 
leafspot control have been modified from Woodroof et al. (172) after 
checking for agreement with Miller (94) and with Wilson and Arant 
(165): 

1. Practice rotations of fields to peanuts at 3-year intervals. Maintain 
vigor of plants by fertilizer, cultivation, etc. 

2. Dust with conditioned dusting sulfur (at least 93 percent through 
325 mesh) or copper-sulfur 10-90 (34 percent basic copper sulfate 10 
parts, dusting sulfur 90 parts). 

3. Begin dusting about 90 days after planting. 

4. Apply dust every 10 to 14 days. If rain occurs within 24 hours 
after first dust, repeat after 7 days. If rain occurs within 12 hours after 
later dusts, repeat dusting as soon as possible. Continue dusting to within 
14 days of harvest. Three to five applications usually are required. 

5. The size of the vines determines to a considerable extent the 
amount of material required for coverage; 12 to 15 pounds per acre of 



PEANUT DISEASES 277 

material will do for first dusting, 15 to 20 pounds per acre for later dust- 
ings. A visible coating of dust should cover the stems and both surfaces of 
leaflets. 

6. Use any tractor or power row-crop duster which will permit di- 
recting some dust at ground to insure bounce to cover lower surface of 
leaflets. A short canvas hood should extend to lower edge of nozzles in 
front and drag the top of the plants behind. This hood permits dusting 
any time except when wind velocities are very high, and insures better 
coverage of the plants. 

SCLEROTIUM BLIGHT OR SOUTHERN ROOT ROT 

Sclerotium rolfsii Sacc. causes three distinct diseases of peanuts : (A) 
Root and crown rot of plants in intermediate and advanced stages of 
growth; (B) soil-rot of pegs (gynophores) and pods of fruits approach- 
ing maturity; (C) blue-black discoloration ("blue-damage") of the seeds 
of Spanish- type peanuts. 

The present discussion is concerned only with the root and crown rot. 
This is the most spectacular disease of the Spanish peanut belt of the 
southeastern United States and, consequently, is known by a variety of 
names. The more commonly encountered names are "southern root rot," 
"southern blight," "blight," "white mold," (sometimes "blue mold") 
and, in other regions, "crown rot," "foot rot" or "Sclerotium wilt." All of 
these names indicate some recognition that the causal organism is a gen- 
eral pathogen and not specific to peanuts. The inclusion of "southern" in 
the name of the disease indicates that the disease is usually confined to 
warmer regions. Of the names given the disease "Sclerotium blight" 
seems preferable since the disease is not confined to peanuts, and is not 
locaUzed in the "South". 

Importance. In the earlier days of peanut production in the United 
States attacks of Sclerotium rolfsii upon the crown region received con- 
siderable attention (2, 88, 150), but for a later period of about 15 to 20 
years this disease attracted attention only in the Spanish peanut region of 
Georgia (91, 92). 

Sclerotium rolfsii has been reported as responsible for deaths of plants 
approaching 50 percent of the stand in some instances in North Carolina 
(113) while another report listed Sclerotium blight as the cause of death 
of as many as 10 percent of the plants (13). Reports from Texas indicate 
considerable loss from the disease every year (1, 149). Other reports 
listed losses from 5*. rolfsii as slight in Mississippi (108) and Virginia 
(150). Some plant pathologists recognize the importance of the disease 



278 THE PEANUT— THE UNPREDICTABLE LEGUME 

but feel that 6". rolfsii may be a secondary invader and, therefore, are not 
wilUng to attribute the losses to this organism. 

Sclerotium rolfsii seldom kills the entire plant of runner peanuts since 
portions away from the point of attack are usually supported by the ad- 
ventitious root system. Therefore, the disease is not as spectacular on 
runner peanuts as on bunch peanuts. There are three general views as 
to the importance of S. rolfsii on runner peanuts : (A) Runner peanuts 
are sometimes regarded as somewhat resistant to S. rolfsii; (B) i'. rolfsii 
is sometimes called an important peg-rotting organism, but an unimpor- 
tant blight-producing organism on runner peanuts; (C) finally S. rolfsii 
is frequently regarded as an important blight-producer on runner peanuts. 

Thus, there is a divergence of opinion as to the importance of this 
disease in the United States. This undoubtedly results largely from a com- 
bination of three factors: (A) The newness of peanuts as a commercial 
crop in some areas ; (B) a tendency to question the parasitism of Sclero- 
tium rolfsii (12, 101) ; (C) the somewhat different end response to at- 
tacks of S. rolfsii exhibited by bunch peanuts as compared with runner 
peanuts. 

Sclerotium blight is well known in other peanut-producing regions. 
In South Africa, where it is known as "foot rot," it has been reported as 
jeopardizing the future of peanut growing (22). In the Philippines, pro- 
grams have been initiated, attempting to discover varietal resistance 
(115). Losses reported for this disease in Peru vary from light to heavy 
(40). A disease has been reported from Rumania (200) and Bulgaria 
(34) that appears to be Sclerotium blight. It is a matter of conjecture 
whether or not the disease is important in such areas as Australia, al- 
though its importance in Ceylon has been questioned (17). 

Description. The two most distinctive characteristics of Sclerotium 
blight are death of above-ground portions of plants and a mat of white 
fungus hyphae and tannish-red sclerotia around stems at the soil surface. 
The entire plant or only one or two branches may be killed (22, 92, 150) . 
When only branches are attacked on bunch peanuts the unattacked por- 
tion may remain healthy and vigorous, or it may be stunted and yellow- 
ish and have few or no nuts at maturity. The unattacked portions of run- 
ner peanut plants usually remain vigorous, although nut production may 
be poor. 

The center of infection is at the soil surface, and death of above- 
ground portions of plants is due to severance of the water-conducting 
tissue of the roots and stems. The leaves usually wilt slowly, reviving at 
night so that wilting is most evident in the middle or later part of the day. 
The leaves turn brown gradually, and several days may elapse before the 



PEANUT DISEASES 279 

branch or plant appears completely dead. Usually the dead leaves remain 
on the branch. 

Death of above-ground portions of the plant sometimes takes place 
very rapidly, particularly in extremely hot weather. When death is ex- 
tremely rapid, the necrosis may develop as a blackening rather than as a 
browning. In such cases preliminary wilting does not occur or is evident 
for a very short time. Under such conditions Sclerotium blight does not 
show the characteristics of a wilt (92). 

From South Africa (23) it has been reported that plants infected by 
Sclerotium rolfsii may be conspicuously robust and healthy due to incom- 
plete disintegration of the vascular bundles with the xylem remaining 
functional. Thus water and minerals move upward, but downward move- 
ment of foods is inhibited and there is a surplus of food for top growth. 

Organism and pathogenicity. The organism associated with Sclero- 
tium blight of peanuts is Sclerotium rolfsii Sacc. This sclerotial fungus 
has a basidial "'perfect" stage which is either a Corticium sp. or a Pellic- 
ularia sp. ( 160) . Other species of Sclerotium have been reported on pea- 
nuts (17, 34, 120) but it seems probable that these are merely forms of 
Sclerotium rolfsii. 

The basidial stage is very rarely found in nature and pathologists have 
continued the use of the name of the sclerotial stage. The fungus is usually 
easily identified by the abundance of tannish-red sclerotia which vary in 
size from .5 to 2 or 3 mm. or larger. Size of sclerotia apparently depends 
upon age, physiological condition, or strain of the organism. The sclerotia 
are generally spherical in shape, but may be flattened or otherwise mis- 
shapen. 

Sclerotium rolfsii frequently produces mycelium on the soil surface or 
on decaying organic matter before sclerotia are evident. This mycelium 
is a dense hyphal mat which fans out from a central point of origin. The 
organism may be identified by microscopic examination since the hyphae 
have double clamp connections. 

The length of the dormant period of the sclerotia of Sclerotium rolfsii 
is governed by food supply and temperature (60). Sclerotia can remain 
viable for a considerable period of time. In the southeastern United 
States viable sclerotia may be found in the soil throughout the year and 
serve as a means of spreading the fungus through or between fields. 

Greenhouse experiments indicate a relationship between organic- 
matter content of soil and parasitism of S. rolfsii on peanuts (54). In 
peanut fields, however, the spots of high organic-matter content are not 
necessarily the spots of maximum death from Sclerotium blight. 

Sclerotium rolfsii is typically a "warm-region" fungus. Its temperature 



280 THE PEANUT— THE UNPREDICTABLE LEGUME 

relations seem to be the limiting factor in its geographical distribution 
(60). In warmer regions it attacks a wide variety of plants, including 
common weeds. The organism has been reported killing almost all cul- 
tivated plants grown in temperate and subtropical zones, including seed- 
lings of forest trees. Members of the grass family are regarded as some- 
what less susceptible, and certain plants such as some varieties of cow- 
peas (73) are reported as appearing to be resistant. 

The general parasitism of S. rolfsii has been thoroughly investigated. 
It seems definitely established that it is a potent parasite on a wide variety 
of plants and that its omnivorousness is due to a peculiar type of parasit- 
ism (60) . The fungus is primarily active in the soil and at the soil surface 
( 54) , and a mat of hyphae is formed over the basal portion of any plants 
growing in spots of the fungus. The fungus clings to the epidermis of 
plants by holdfasts, and the hyphae secrete considerable quantities of 
oxalic acid. Cells of the plant are killed by this oxalic acid in advance of 
the fungus hyphae (60). The hyphae apparently do not penetrate living 
cells, but will grow into cells killed by oxalic acid. Thus, any plant with 
an epidermis permeable to oxalic acid will be killed by contact with the 
fungus. 

The factors affecting the parasitism of Sclerotium rolfsii, are centered 
in the physiological activities of the fungus and not in the reactions of the 
host. That the physiology of this fungus in the soil is variable is indicated 
by its peculiar behavior in peanut fields. Infections are spotted and these 
spots do not appear in the same place in the field from year to year. They 
do not appear to be related to soil differences, spots of high organic con- 
tent, spots of variable drainage, or any other easily discernible factor. In 
a given season, there seems to be no tendency for the fungus to spread out 
of these spots. 

It has been shown that Sclerotium rolfsii can be seedborne in 
peanuts (41, 54, 64, 72, 111, 149), but the possibility of infection from 
this source is greatly overshadowed by the possibility of infection from 
the soil (142). 

Control. At present there seems no basis for making positive recom- 
mendations for control of Sclerotium blight on peanuts or other crops. 
Although there have been occasional reports of apparent resistance in 
progeny resulting from peanut breeding and selection programs (54, 
116), the nature of the attack of Sclerotium rolfsii suggests that resist- 
ant varieties of peanuts are improbable. There is no reason to expect dif- 
ferences in permeability of the epidermis to oxalic acid. There has been 
a persistent contention that runner peanuts are less suceptible to Sclera- 



PEANUT DISEASES 281 

Hum blight than are bunch types (22, 92), but many observers feel that 
this is actually a difference in response to attack resulting from a differ- 
ence in habit. 

In the United States it is believed that attacks of Sclerotium rolfsii on 
peanuts are less severe in heavy (92) or poorly aerated land (54). In 
South Africa it is indicated that well-drained friable soils should be used 
for peanut culture to reduce losses from Sclerotium blight (64), although 
the disease has been reported from this region as equally severe on all soil 
types (22). In Georgia, Sclerotium rolfsii seems less severe on heavier 
soils, but these soils are not particularly adapted to peanut culture and are 
usually avoided by peanut growers. Deep plowing, recommended in 
South Africa for control of Sclerotium blight (22), has not been tho- 
roughly tested in the United States. 

The number of susceptible crops suggests that it is impractical to 
eradicate Sclerotium blight by crop rotation (92). It is reported from 
North Carolina that there appears to be no relationship between previous 
crops and prevalence of the disease on peanuts (13). In Virginia, how- 
ever, an apparent correlation has been observed (150). In South Africa 
it is suggested that peanut fields may be cleared of the fungus by follow- 
ing peanuts with a grass crop for 2 years, then another legume such as 
soybeans the third year (22). Also, in South Africa it is thought that 
virgin soils should be planted to a nonsusceptible crop for a year or two 
before planting to peanuts (22) . In Texas it is recommended that infested 
peanut fields be replanted to the apparently resistant varieties of cow- 
peas (72). In Georgia a preliminary survey indicated that Sclerotium 
blight is more severe on peanuts following peanut?, cotton or lupine than 
on peanuts following corn or small grain (52). 

Some soil treatments have been tested for control of Sclerotium blight 
of peanuts. One test reported no results (92). A report from North Caro- 
lina in 1938 indicated beneficial results from some inorganic elements 
added to fertilizer and from sulfur and lime appHcations (111). In 1941, 
also from North Carolina, some control was reported from heavy appli- 
cations of copper and sulfur to the surface of the soil in peanut rows dur- 
ing July and August (101). 

At present, therefore, only general recommendations for control of 
Sclerotium blight can be made. These include : 

A. Plant good, carefully treated seeds to insure proper stand estab- 
lishment and initial vigor. 

B. Plant seeds thickly to insure good stands. 

C. Maintain vigor by dusting for leafspof. 



282 THE PEANUT— THE UNPREDICTABLE LEGUME 

D. Harvest peanuts as soon as practicable from fields in which 
Sclerotium blight is bad. 

E. Abandon from peanut culture for several years fields in which 
Sclerotium blight appears exceptionally severe. 

F. Follow a strict rotation policy in which grass crops play a promi- 
nent role in all peanut fields. 

DISEASES OF MATURATION— SOIL ROTS OF FRUITS 
(PEGS AND PODS) ' 

In the following discussion the gynophore or fruit stalk is called the 
"peg" and considered a part of the peanut fruit. The shell and seed por- 
tion of the fruit is called the "nut" or "pod." The peanut fruit is usually 
called a "peanut" or a "nut." The peanut differs from most legumes in 
that the fruit matures underground and in that the gynophore is con- 
siderably elongated. This elongated fruit stalk is usually called the "peg," 
although shriveled, under-developed peanut seeds are also called "pegs" 
in some sections. 

Importance. By harvesting time in the southeastern United States 
many nuts are partially or completely rotted and many seeds of Spanish 
peanuts have sprouted in the pod. Many nuts pull off the vines and are 
left in the soil. These losses result either from rots or from the pegs be- 
coming mature, brittle or otherwise weakened before harvest. These path- 
ological and physiological factors are undesirable aspects of the matura- 
tion process and are "maturation diseases." 

Several surveys have noted these maturation diseases as important in 
peanut culture (11, 95, 96, 119, 125, 127) and a few figures or estimates 
of importance are available. In \'irginia and North Carolina in 1931 
(95) up to 10 percent of the marketed nuts were rotted or "pickouts." 
The same year losses due to soil rots were estimated as : Virginia 5 to 10 
percent ; North Carolina 5 percent average ; South Carolina 5 percent aver- 
age on most soils ; Georgia 10 to 30 percent in most localities and up to 
50 -percent in others ; Alabama from 1 to 30 percent in various localities 
(98). Surveys in 1943 estimated losses from maturation diseases as: 
Virginia 30 percent in one section and from 5 to 50 percent in all sections 
(150) ; North Carolina a loss of $20 to $50 per acre; Alabama an esti- 
mated average of 12 to 15 percent (139). 

Description. Following pollination the peduncle (gynophore) of the 
pistil elongates rapidly and becomes the peg. This forces the ovulary into 
the soil where most development takes place. Usually at maturity all of 
the nut and most or all of the peg are in the soil. The peanut fruit ma- 
tures, then, under conditions conducive to attacks of microorganisms. 



PEANUT DISEASES 283 

If fungi infect the peg it may decay the pod in the soil, or it is weak- 
ened so that the pod is puUed-off in the soil or otherwise lost in harvest- 
ing. Attacks upon the nut result in discoloration or decay of the shells and 
eventually in discoloration and partial or complete decay of the seeds. 
This fungous invasion of the maturing peanut fruit may be facilitated by 
insect or nematode action (113, 161) but it is not dependent upon this. 

Preharvest sprouting of seeds is frequent in Spanish peanuts and 
certain peanut varieties other than the common runner that do not re- 
quire an after-ripening period before germination. Large numbers of 
sprouted seeds are found on Spanish peanut vines when the pegs show 
evidence of considerable fungous infection. This indicates that fungi may 
be responsible for considerable preharvest sprouting of seeds. Probably 
infection of the peg stops the movement of water and food materials re- 
sulting in premature ripening and abnormally early germination. 

Infection of the peg, however, is the only one of the causes of breaking 
of pegs at harvest ( 139) . At maturity all vegetative parts of the plant are 
brittle. Premature leaf shedding from disease or insect attacks also has- 
tens vegetative maturity and the pegs become brittle abnormally early. 

Organisms. Peg breaking or seed damage may result from action of 
a number of common soil fungi. Fungi isolated from soil-rotted peanuts 
(13, 96, 109, 113, 118) and from peanut seed stocks (41, 44) show that 
a variety of saprophytic and parasitic fungi is associated with pod rots. 
Nematodes have also been reported as a cause of damage to peanut pods 
(113). 

Somewhat detailed isolations (161) showed about one-half of the 
rotted fruits were infected with miscellaneous molds {Penicillia, Asper- 
gilli, Rhizopus spp., etc.). The remainder were infected with Sclerotium 
rolfsii, S. bataticola, Diplodia sp., Rhizoctonia spp., or Fusaria. S. rolfsii 
was reported several years ago ( 168) as a cause of peanut fruit rots and in 
1931 (91, 98) and 1943 (150) it was reported as the predominant organ- 
ism apparently associated with soil rots of peanuts. The variety of fungi 
isolated from field-rotted nuts ( 161 ) suggests that 5". rolfsii is usually not 
the most important organism, but rather is only one of several important 
organisms. 

Early defoliation of plants also causes peg breaking. Thus any dis- 
ease or insect injury resulting in leaf shedding will increase losses due to 
peg rot. 

Some cases of peg breaking can only be blamed on over-maturity of 
the pegs at harvest. This is a result of miscalculations and cannot be 
called a disease. 

Control. Since maturation diseases are affected by several factors. 



284 THE PEANUT— THE UNPREDICTABLE LEGUME 

control measures consist mainly of management practices that increase 
the vigor of the plant and prevent premature defoliation. Control of leaf- 
spot and leaf insects tends to keep the pegs from becoming brittle pre- 
maturely and decreases invasion of pegs by saprophytic fungi and the 
natural breaking of pegs at harvest. Apparently fertilizer applications 
may sometimes result in more peg breaking at harvest (57). There have 
been suggestions of varietal differences in peg breaking at harvest (82), 
but more evidence is needed before definite conclusions can be drawn. 

Pending further study the following strictly tentative recommenda- 
tions for control of maturation diseases are suggested : 

A. Keep plants as vigorous as possible up to harvest. 

B. Follow a dusting program for control of leaf diseases and insects. 

C. Avoid planting peanuts on fields where Sclerotium blight has been 
severe on peanuts in the past. 

D. Avoid planting peanuts on fields where nut rots, peg breaking, or 
seed sprouting has been severe in the past. 

E. Make frequent checks on pegs and pods toward the end of the 
growing season. If pegs or pods are beginning to rot, harvest the 
crop immediately. If no rotting is evident, harvest the crop before 
the pegs become brittle from natural maturity. 

DISEASES OF CURING 

Since the peanut pod develops in soil it is subject to attack by a host 
of soil fungi. This invasion begins early (161), and fungi are associated 
with the fruit after peanuts are cured (44, 48, 114, 162). If this invasion 
were confined to the shell, it would be unimportant, but fungi frequently 
grow through the shell and around or into the seeds. This results in 
damage to the seeds. 

When peanut vines and nuts are stacked, piled or windrowed for cur- 
ing, the environment becomes ideal for growth of fungi (49). During 
curing, then, there is an excellent opportunity for development of damage 
to seeds which were undamaged at digging. Concealed damage and blue 
damage are two distinct types of seed damage that develop primarily 
during the curing process (48, 49, 162). 

CONCEALED DAMAGE 

Importance. Concealed damage — sometimes called "hidden damage" 
— is a type of seed damage not visible until the seed is broken open. Its 
nature, therefore, insures it some importance for its "nuisance value." It 



PEANUT DISEASES 285 

is found most frequently in certain varieties of peanuts, but the possibility 
of its presence in any variety makes necessary elaborate and time-consum- 
ing sampling procedures. Since the price that the grower receives for 
peanuts is determined by the shelling percentage and by the amount of 
damage in the sample, concealed damage often becomes very important. 
It was estimated that in 1945 farmers in Alabama alone lost 2j4 million 
dollars from penalties imposed because of damage (162). 

The importance of concealed damage in any given locality depends 
largely upon the variety of peanuts grown. Concealed damage is some- 
times found in Spanish peanuts (114, 162) but it is rarely of any conse- 
quence (48, 162), so that in areas where Spanish is the predominant 
variety concealed damage is of slight concern. Farmers in other areas 
(162), however, find concealed damage very important. A newer variety, 
Dixie runner (30) , appears to be less susceptible than the common south- 
eastern runner (30, 52, 82, 156, 162). Concealed damage has never been 
considered important in Virginia-type peanuts. 

A preliminary study of varietal susceptibility has been made in 
Georgia (52). From this and other observations the following tentative 
grouping of peanut varieties according to apparent susceptibility to con- 
cealed damage is offered : 



Very susceptible 


Intermediate 


Southeastern runner 


Dixie runner 


(Alabama, Georgia, or Florida 




runner, etc.) 




Susceptible 


Somewhat resistant 


Georgia bunch 


Virginia runner 


North Carolina bunch 


Virginia bunch 


llncertain 


Resistant 


Jumbos 


Spanish 


Valencias, etc. 





Preliminary data indicate that some unreleased hybrids and selections 
of the large-seeded type are more resistant to concealed damage than is 
Dixie runner (52). Even though apparent resistance to the disease is not 
yet fully explained there is hope that resistant large-seeded varieties will 
replace the susceptible types. 

Description. Concealed damage is seed decay beginning at the inter- 
face between cotyledons and developing outward. The first evidence is a 
slight discoloration of this interface, and this is usually followed by defi- 



286 



THE PEANUT— THE UNPREDICTABLE LEGUME 



nite yellowing. With this yellowing a mycelial mat is usually found be- 
tween the cotyledons but sometimes this mat is found before discoloration 
of the cotyledons is evident. As the disease progresses, the mycelial mat 
and cotyledons become darker and eventually the entire seed becomes 
black or dark purple. The decay may gradually become apparent from 
the exterior of the seeds so that the seed coat becomes shriveled, its color 
fades, the seed appears oily, and feels soft (48, 162). Even in this stage, 
however, the seed appears normal to all but the most experienced ob- 
servers. These symptoms are shown in figure 2. 

This semi-detectable stage is soon succeeded by a stage in which the 
dark decomposition products are visible from the exterior. At this stage 














Courtesy Alabama Agricultural Experiment Station 

Figure 2. — Concealed damage in runner peanuts. Outside and inside views of healthy- 
seed at left and damaged seed at the right. The damage on the seed at the ex- 
treme right is no longer concealed. 

the damage is no longer concealed, but is visible (48, 162). After the 
seed are completely decayed it is not possible to determine whether the 
infection spread from between the cotyledons or developed inward from 
the surface. The important factor is the period in concealed damage dur- 
ing which seeds with partially decayed cotyledons appear to be perfectly 
sound seeds. 

Seeds with concealed damage have a strong, rancid taste (162). 
This is the primary danger since a few of these seed taint an entire pro- 
duct. In processing peanuts these seed are difficult to avoid since bitter- 
ness develops before external symptoms. In addition to rancidity there is 
an increase in free fatty acids (162), 



PEANUT DISEASES 287 

Two other types of interior damage can be confused with concealed 
damage. In one type the interior of the cotyledons is shrunken, cracked 
and discolored reddish-brown. Apparently this is a physiological trouble ; 
no fungi have been isolated from these cotyledons and there is no ran- 
cidity. It is rare (162) but has been found in several varieties and is 
found more frequently in Virginia peanuts than is concealed damage. 
The other type, a soft rot apparently beginning in the "germ," is rarely 
noted (162). 

Organisms and pathogenicity. Mycelial mats between the cotyledons 
of concealed damaged seeds suggest that a fungus is concerned, and the 
disease has been reproduced by inoculations with fungi isolated from 
seeds with concealed damage (48). 

The lists of fungi isolated from concealed damaged seed in Georgia 
(48) and Alabama (162) are strikingly similar. Diplodia sp.^ made up 
almost 90 percent of the isolations in both cases. Miscellaneous sapro- 
phytes — Fusaria, Aspergilli, Penicilli, Sclerotium hataticola, etc. — ac- 
counted for the bulk of the remainder. Parasitic forms such as Rhizoc- 
tonia solani and Sclerotium rolfsii were rare. S. hataticola, however, was 
isolated more frequently in Georgia (48) than in Alabama (162). 

Inoculation tests have shown that Diplodia sp. can produce concealed 
damage (48). Therefore, it is regarded as the predominant organism in- 
volved. Concealed damage was also reproduced by inoculation with 
Sclerotium hataticola and perhaps one or two other fungi (48). Thus, 
while most concealed damage is due to Diplodia sp., other fungi can and 
sometimes do cause the damage. It has been suggested, however, that 
Diplodia sp. is the pathogen and other fungi are secondary invaders (162). 

Concealed damage usually results from infection which takes place be- 
fore peanuts are dug (162). The same fungi may be isolated from sound 
seeds and from concealed damaged seeds (48). Concealed damage is 
found when peanuts are bought on the market but the disease is rare in 
freshly dug peanuts and then is found only in the early stage. It is ap- 
parent, therefore, that concealed damage develops primarily during the 
curing season. 

The causal fungus invades the intercotyledonary space through the 
shell and the placenta (48). Thereafter growth of the fungus is condi- 
tioned by moisture content of the seed. The damage develops most rapidly 
in green peanuts with moisture contents IS to 35 percent (162). Above 

» The taxonomy of the form genus Diplodia is extremely confused. The fungus isolated from 
concealed damaged seeds could he put in any of feveral species including three species originally 
described from peanuts. The present report prefers to regard it as "Diplodia sp." until it has been 
studied further. 



288 THE PEANUT— THE UNPREDICTABLE LEGUME 

and below these moistures, concealed damage develops slowly, with little 
development below 10 percent. There seems to be no relationship between 
soil type or fertilizer practices and development of concealed damage. 
It may be more prevalent, however, when fields are cropped continuously 
to peanuts. 

Control. Moisture content being closely related to development of 
concealed damage, control measures are centered in attempts at rapid 
drying of seeds. Since artificial curing with dry air is still in the experi- 
mental stage, control of concealed damage at present is dependent upon 
some variation of field curing that hastens the removal of moisture. 

The safest method of field curing peanuts is stacking rather than 
windrowing or piling in "cocks" (166). Preliminary studies in Florida 
(21) have shown no relation between method of stacking and concealed 
damage, but similar studies in Georgia (52) have indicated that signifi- 
cantly less concealed damage develops when plants are stacked wilted 
(not brittle) than that which develops when plants are stacked "green" 
or unwilted. 

BLUE DAMAGE" 

Importance. Spanish peanuts reaching the market are frequently 
graded down because of a prominent blue-black discoloration of many 
seeds. In some years this discoloration is not troublesome, but in other 
years peanut shellers have reported losses up to 25 percent from this 
disease. Sometimes entire lots are rejected by peanut brokers because of 
this discoloration. 

Description. Usually when blue damage is found in a seed lot, a large 
proportion of the seeds is conspicuously affected, though sometimes only 
very few seeds are damaged. The discoloration may occur in such an 
inconspicuous form and on so few seeds that it is easily overlooked. 

This discoloration varies through several shades of blue-black. One 
spot may be of several shades, or different spots on the same seed may be 
of dififerent shades. Sometimes the discoloration is a streak following 
either veins of the seed coat or the suture between cotyledons. The spots 
vary in size. The smallest are about 2 mm. in size and of a distinct "bull's 
eye" type with centers bleached, slightly darker, or the natural color of 
the seed coat. Larger spots are irregular in shape with no evident center. 
All possible variations can be found in a single lot of discolored seeds. 

Spanish peanut lots containing blue-damaged seeds generally have 

'"This section is a condensation of the report by Garren, Higgins and Futral (49), the only 
published work on this disease to date. 



PEANUT DISEASES 289 

more discolored or otherwise damaged shells than do other lots. These 
shell characteristics, however, are sometimes found on shells that do not 
contain discolored seeds. In some instances the cotyledons beneath dis- 
colored seed coats are not discolored, but generally there is slight yellow 
or blue-black discoloration. A few cotyledons underneath discolored seed 
coats are conspicuously discolored. 

The nitrogen and oil content of blue-damaged seeds and seed coats is 
not different from that of normal seeds. The discoloration apparently does 
not result in important changes in chemical constituent of the seeds. Ac- 
cording to preliminary tests there is no detectable rancidity or off-flavor 
in blue-damaged seeds nor does the discoloration have any effect on ger- 
mination of the seeds or vigor of seedlings. 

Organism and Pathogenicity. Numerous unsuccessful attempts to 
isolate fungi from the discolored spots have been made. In rare instances 
Sclerotium rolfsii was isolated. It seems apparent, therefore, that the dis- 
coloration results from chemical reaction of pigments of the seed coat. 
Several facts were evident : Sclerotium rolfsii grew from a few of the dis- 
colored spots; it grew readily from shells which contained discolored 
seeds; it was known to be prevalent in fields in which Spanish peanuts 
were grown ; and S. rolfsii secretes oxalic acid which diffuses into plant 
tissue in advance of hyphae. A test was made, therefore, in which crystals 
of oxalic acid were kept against nuts on living plants in damp soil for 
72 hours. Typical blue damage resulted. Inoculation of peanuts with S. 
rolfsii resulted in the production of a considerable percentage of blue- 
black discolored seeds. Application of liquid from an autoclaved culture 
of 6". rolfsii to green or partially cured nuts resulted in a lighter form of 
the discoloration. It seems evident, therefore, that the discoloration is an 
indicator reaction involving pigments of the seed coat and oxalic acid 
secreted by 5". rolfsii growing in or on the peanut shells. 

Most fields of Spanish peanuts in the southeastern United States are 
infested with 5". rolfsii. When weather conditions or curing methods pre- 
vent the rapid drying out of the curing plants there may be continued 
growth of S. rolfsii from infested plants in the curing lot. Field studies 
show an interrelationship between curing methods, weather conditions, 
and development of blue damage. Prominent discoloration is not found 
in peanuts cured in stacks during hot, dry weather, but pronounced dis- 
coloration is found in peanuts cured in stacks during warm, damp 
weather. The blue-black discoloration does not develop in quick-cured 
peanuts taken from the same field as peanuts in which blue damage de- 
velops during slow curing in warm, damp weather. It is apparent, there- 



290 THE PEANUT— THE UNPREDICTABLE LEGUME 

fore, that the discoloration develops after peanuts are dug. Development 
of the discoloration in peanuts still in the soil or in peanuts in storage 
seems negligible. 

Control. Considerable development of blue damage is reported from 
areas where field windrowing is used for curing peanuts. Absorption of 
moisture from soil and dew apparently promotes saprophytic growth 
of Sclerotium rolfsii. 

Since weather conditions cannot be controlled and since rapid curing 
by artificial means is not a general practice, the best control measure at 
present is stack curing. If the peanuts are allowed to wilt before stacking, 
symmetrical stacks can be constructed that will facilitate curing. 

STORAGE DISEASES— ROTS AND OTHER DISORDERS 

Importance. Disorders developing in stored peanut fruits or seeds are 
of importance primarily to peanut brokers and processors. An occasional 
rotten or rancid seed may ruin a peanut product (169). 

No information is available regarding the importance of storage 
diseases of peanuts to the peanut industry but personal conversations 
indicate that considerable loss sometimes is incurred. 

Description. Of the disorders developing in stored peanuts, some are 
pathological and some are purely physiological. The pathological develop- 
ments may have physiological end effects which obscure the initial patho- 
logical activity. Rancidity, for example, may develop from undetectable 
or incipient concealed damage, from visible rot, or from an independent 
enzymatic reaction within the embryo. 

Table 4 lists the major storage disorders of peanut seeds, with prob- 
able initial causes. 

Of these storage disorders, rots, rancidity and reduced vitality are 
more frequently encountered. Seed-coat discolorations and bleaching not 
accompanied by rot do not afifect the use of the seeds for most processing 
or for seed stocks (49). Brittleness and sogginess in stored seeds may be 
accompanied by physiological changes of a detrimental nature, but this 
can not now be confirmed. 

Blue damage and concealed damage undoubtedly can develop during 
storage of peanuts, but neither has yet been found developing to any con- 
siderable extent in storage (48, 49). Progress of concealed damage into 
seed rot during storage is probable also (48, 162), but has not been veri- 
fied. Reduction in vitality of seeds during storage, the physiological 
activities involved, and the factors affecting these physiological activities 
are also suppositionary at present. 



PEANUT DISEASES 



291 



Organisms and factors involved. As discussed previously, a fungus 
flora develops in the peanut fruit in the soil (48, 161) and viable fungi 
are associated with peanut fruits and seeds after curing (48, 114, 162) and 
storage (44). These are primarily saprophytic fungi (44, 48, 114, 162) 
which may, under favorable conditions, produce rot or other seed damage. 

The activity of fungi will be conditioned or limited by a number of 
factors. The most important of these factors appears to be temperature, 
moisture and time. Thus, rots, discolorations and fungus-produced ran- 
cidity and flavor changes which occur in storage will be influenced by 



Table 4. — Major Storage Disorders of 


Peanut Seeds 


Disorder 


Initial cause 


Reference 


Concealed damage 

Seed rots 


fungi 

fungi, bacteria 

fungus 

fungi or enzymatic 

fungi or enzymatic 

low moisture 

high moisture 

fungi, or bacteria or 
enzymatic 

fungi, enzymatic, etc. 


(48, 162) 

(170) and common 
observations 

(49) 


Blue damage 

Other seed coat 

discolorations 


Seed coat bleaching 

Brittleness 


Common observation 

(170) 

(170) 

(162) 
(170) 

Common observation 


SoffSfiness 


Rancidity 

Reduced vitality 

(germination) 







these same factors. Woodroof et al. (170) studied moisture content in 
relation to fungus development in stored peanuts. Their results indicate 
that unshelled, untreated, raw peanuts do not become evidently molded 
when stored at 6 per cent moisture or below, become slightly molded 
when stored at 6.5 to 7.5 percent moisture, and become pronouncedly 
molded at 10 percent moisture or above. For shelled peanuts the moisture 
content at which fungus development becomes evident and pronounced is 
slightly higher. 

In this same study (170) the effect of relative humidity of the 
storage atmosphere plus time of storage on fungus development were 
tested. At 80 percent relative humidity fungus development was evident 
at 120 to 180 days and pronounced after 240 days. At 65 percent 



292 THE PEANUT— THE UNPREDICTABLE LEGUME 

and 50 percent relative humidity no pronounced fungus development 
was noted at the end of 360 days. It is indicated, indirectly, that peanuts 
stored at 80, 65 and SO percent relative humidity will have moisture con- 
tents of approximately 10, 6.5 to 8, and 4 to 6 percent, respectively ( 170) , 
and the effect of relative humidity on fungus growth must be through 
the moisture content of the seed. 

Some rancidity developing in storage is not associated with fungus 
activity but the result of enzymatic action. This also appears to be con- 
ditioned by the factors of temperature, moisture and time. In the same 
study (170) rancidity was measured by means of organoleptic tests and 
peroxidase values. In general, rancidity developed along with or slightly 
earlier than evident fungus activity. Apparently no attempt was made to 
determine whether any rancidity developed independent of fungus 
activity. It was concluded, however, that "at 50 percent relative humidity 
storage life depends primarily on the development of oxidative rancidity 
or some other factoi^ independent of moisture changes. . . ." Apparently 
at 50 percent relative humidity rancidity does not develop as soon as it 
does at 65 or 80 percent, but once beginning it develops more rapidly 
(170). This may mean that rancidity developing at 50 percent relative 
humidity is purely enzymatic in origin. 

Brittleness and sogginess are primarily a matter of moisture lost 
or absorbed by the cotyledons. Brittleness develops when the moisture 
content falls below 4 percent and sogginess develops at moisture content 
above 10 percent. It may be assumed that the loss of viability of peanut 
seeds in storage will be closely correlated with fungus and enzymatic 
activity and thus conditioned by the same factors. 

Control. Peanut brokers, in general, avoid storing peanuts with 
moisture, content above 8 to 10 percent, but the study cited ( 170) recom- 
mends that the moisture content of stored peanuts should be held at 
about 5 percent with the storage atmosphere at about 60 percent relative 
humidity. 

Present recommendations for control of storage diseases of peanuts 
may be summed up as follows: 

A. Cure and dry the peanuts as thoroughly as possible before storage. 

B. Control aeration in the storage area so that the relative humidity 
of the storage atmosphere is kept as low as possible. 



PEANUT DISEASES 293 

PEANUT DISEASES OF MAJOR IMPORTANCE 
IN OTHER AREAS 

Virus diseases, bacterial wilt, and rust — major diseases in some 
peanut-producing regions — have never been considered important in 
the United States. Both viroses and bacterial wilt appeared in the East 
Indies and spread to other regions. Virus diseases are of major im- 
portance in Africa; bacterial wilt is of major importance in the East 
Indies. Peanut rust is a disease of the West Indies, but has been re- 
ported from Africa and the United States. 

VIRUS DISEASES OF PEANUTS 

General 

History. In 1907 a peanut "krauselkrankheit" (curl disease) was re- 
ported from Java (175). According to Storey and Bottomley (143) a 
similar or identical disease was noted in South Africa about 1909. 

The name "rosette" was applied to the South African curl disease 
about 1925 (3, 143). Storey and Bottomley in 1925 (143) regarded 
rosette as definitely a virosis and transmitted the disease. Rosette was 
reported from equatorial Africa in 1926 (24), and was reported ex- 
tensively from the African region thereafter. In 1945, rosette was 
noted as one of the three most important diseases of peanuts in Rhodesia, 
South Africa (64). 

Virus diseases other than rosette have been reported from other 
areas. Mosaic was reported on peanuts in Argentina in 1936 (133) and 
in China in 1939 (174). In 1941 Costa (38) described a "ring spot" of 
peanut in Brazil as a virosis. KenKnight in 1941 (75) reported a trans- 
mittable virus disease, called "stunt," of peanuts in Texas. Jensen in 
1948 (71) regarded virus diseases of peanuts as apparently unimportant 
in North Carolina but recognized the following: A leaf mottling 
(mosaic?) as a transmittable virosis; a ring spot as a fairly definite 
virosis; a rosette-like disease and a witches'-broom, both somewhat in- 
definite as to nature at present. Similar conclusions were later reached 
by Cooper (37), and most of these conditions have been reported from 
Australia (99). At present, then, there are only four described diseases 
of peanuts more or less definitely connected with viruses: Rosette, 
mosaic, ring spot, stunt. 

There is considerable confusion as to the various viroses or probable 
viroses of peanuts. Several different conditions have been described as 



294 



THE PEANUT— THE UNPREDICTABLE LEGUME 



probably due to the rosette virus (158). Typical mosaic conditions have 
been described from Africa (56) and the East Indies (175) as rosette, 
and yet mosaic has been reported by observers unwilling to regard it as 
a phase of rosette. In spite of this confusion, however, certain tentative 
conclusions may be reached, largely as a result of opinions expressed. 

ROSETTE 

Importance. Several reports include statements which may be used 
in evaluating the importance of the virus disease called "rosette." This 
information is condensed in table 5. 



Table 5. — Estimates of Importance of Rosette 



Year of 
report 


Area 
reported on 


Observations on 
importance of rosette 


Reference 


1907 


East Indies 


Serious loss 


(175) 


1945 


South Africa 


One of 3 most important diseases 


(64) 


1926 


Gambia 


78 percent infection, yield decrease 
66 percent 


(81) 


1937 


French West Africa 


75 to 80 percent loss 


(107) 


1937 


Ivory Coast 


Vine weight loss 61 percent 
Pod weight loss 81 percent 


(112) 



Description. Rosette is characterized by a "condensation" of the 
plant. Petioles and internodes are shortened, giving the plant a typical 
rosette or clumped appearance. Storey and Bottomley in 1928 (144) 
gave a detailed description of peanut rosette as it was then recognized, 
and the following description is condensed from their report: 

The whole plant is severely stunted. Leaves, especially the 
younger ones, are more or less definitely chlorotic and faintly mottled. 
New leaves are pale yellow with dark green veins. Successive leaves 
are smaller, curled and distorted, uniformly yellow, and without 
green veins. These leaves usually turn green and eventually appear 
almost normal. Yield depends upon time of infection. If infection is 
early, small, sessil flowers which do not open may be formed, but 
they do not mature into fruits. If plants are infected after seeds begin 
forming low yields may be obtained. The disease is transmitted by 
grafting, is not seed-borne, or soil-borne. 

An earlier observation indicated a general deterioration of infected 



PEANUT DISEASES 295 

plants before the disease became visible. This would result in a reduced 
number of nuts with many seedless pods (24) . Nuts, formed on rosetted 
plants, were also noted as having a lower shelling percentage (27). 

It appears that at least two distinct types of symptoms, other than 
the typical, have been recognized and called rosette, and subtypes or 
variations of each in turn have been recognized and described. The fol- 
lowing outline is based upon various published descriptions and the 
summary of Weiss (158). 

VARIATIONS OF ROSETTE 

(A) Typical rosette (Storey and Bottomley (144)). 
(See description above) 

(B) Chlorotic rosette 

Variation 1. Mosaic rosette: Mottling of leaves, no marked 
yellowing. Less severe stunting or resetting (Storey and Bot- 
tomley (144) and Hansford (56)). 

Variation 2. Yellows: More pronounced chlorosis, very pro- 
nounced mosaic. No typical resetting (Hansford (56)). 

(C) Nonchlorotic rosette. 

Variation 3. Green rosette: Leaves darker green than normal. 
No chlorosis (Hayes (59) and Porteres and Legleu (112)). 
Variation 4. Clump rosette: Leaves normal green in color, 
rosette condition more pronounced than typical or other 
variations (Porteres and Legleu (112)). 

Of these variations the mosaic type and the clump type are infrequent 
(56, 112), while typical rosette and yellows have been reported as having 
the greatest effect upon yield (56). 

The Virus and pathogenicity. There are no indications that the virus 
(or viruses) associated with rosette has been isolated or otherwise studied. 
Weiss (158) recognized two acceptable technical names for the virus — 
Arachis Virus 1 or Marmor arachidis. 

Peanut rosette has been transmitted by grafting (144) and by the 
legume aphid (135, 143). Later reports noted that the disease could not 
be transmitted to other legumes (141) nor could a rosette-type disease of 
a wild plant in the Congo be transmitted to peanuts (135). Weiss, how- 
ever, lists a butterfly pea, Centrosema plunieri Benth. as another host of 
the virus (158). 

The legume aphid, Aphis leguniinosae Theob. is considered to be the 
vector of peanut rosette virus (135, 143). Other insects, which have been 



296 THE PEANUT— THE UNPREDICTABLE LEGUME 

suspected in regions where the legume aphid is rare, appear to have been 
eHminated from consideration. 

Several factors seem to influence the pathogenicity of the rosette virus. 
These factors, obviously, may be efifective on the peanut plant or on the 
aphid vector. The most important factors are : 

(A) Season. In Africa late plantings are more severely attacked by 
rosette (24). Plants not infected during the first 8 weeks of the season 
apparently remain uninfected (25). Rosette has been reported more 
prevalent (27) and spreading more rapidly (24) in dry seasons. 

(B) Soil Moisture. Possibly many of the apparent seasonal effects 
are actually effects of variations in soil moisture. An early report indi- 
cated a greater degree of susceptibility to rosette during a rainy period 
following a long drought ( 175) . If there is scant rainfall in the first month 
of the growing season, rosette may be intensified (25). 

(C) Vegetative covering. Certain observations indicate that denser 
vegetative coverings in peanut fields make for less severe rosette. Weed- 
ing does not prevent the spread of infection, but weed covering between 
peanut rows apparently results in reduced infection (27, 59, 135). Plants 
on the border of a field are reported most frequently infected (59). 
Whether these effects are independent of the effect of shading on soil 
moisture is not clear. Possibly there is some effect of these dense vege- 
tative coverings on the vector. 

Control. Some reports from Africa (25) have indicated that com- 
monly grown varieties are susceptible. In the Gambia region, the Philip- 
pine pink, a local section from Tennessee red, is regarded as resistant 
(26) with the Philippine white either less resistant than the pink or not 
resistant at all (26). 

From Gambia (6) and the Congo (7) it is reported that various con- 
trol measures have reduced the incidence of rosette so that it is no longer 
serious. The following control measures have been recommended in ad- 
dition to the use of resistant varieties : 

(A) Seed treatment, insuring good stands and vigorous, drought- 
resistant plants (64). 

(B) Early planting (142). 

(C) Rotation — the disease is reported more severe the second season 
on the same land (135). 

(D) Close planting for greater covering of soil surface (142). 

(E) Roguing of volunteer peanuts (142). 

(F) Roguing of infected plants (112), 



PEANUT DISEASES 297 

( G) Spraying for control of vector ( 107) . 
(H) Grass mulching of soil (141). 

BACTERIAL WILT— SLIME DISEASE 

Importance. Bacterial wilt or "slime disease" i^, the first recorded 
important disease of peanuts, was observed in the East Indies around 
1905 with losses of at least 25 percent (23). The disease was investigated 
extensively in the East Indies thereafter until 1937 when a gradual de- 
crease in the importance of the disease was noted ( 154). Slime disease of 
peanuts was reported, without estimates of importance, from various 
regions and in South Africa the disease became of sufficient importance 
for an extensive study to be made in 1930 (87). 

In the United States bacterial wilt of peanuts has generally been 
regarded as of minor importance. The disease was noted in North Caro- 
lina in 1912 when about 15 percent of Spanish peanuts on soil known to 
be infested were diseased (47). Wartime plant disease surveys (1944) 
reported some bacterial wilt of peanuts in the United States ( 13, 140) . 
Experimental host range studies made in North Carolina in 1917 sub- 
stantiated the general conclusion that the disease is relatively unim- 
portant on peanuts in the United States since peanuts were placed in the 
"very slightly susceptible" class (131). 

Description. As slime disease of peanuts was observed in the East 
Indies, attacked plants usually wilted rather suddenly with leaves on dead 
plants sometimes remaining green (23, 106). Slight, early infections, how- 
ever, were usually overcome ( 106) . Apparently the disease developed pri- 
marily in patches and general attacks over an entire field were very rare 
(23). In contrast to this are the descriptions given from the United 
States where the disease appears to be much milder (92, 136) . 

The attack of the causal organism is centered in the conducting cells 
of the roots and stems (23). One diagnostic characteristic is a large 
number of dead roots (106). Bacterial colonies form throughout the root, 
main stem and lower branches (23) . These colonies are evident as streaks 
of brown or black discolorations (23, 106). The original point of entrance 
is possibly an insect wound or a lenticle (143). The infected tissue is 
finally blackened with extensive plugging and necrosis. If young plants 
are attacked the pods are invaded and remain small (106) or become 
wrinkled and develop a spongy decay (23). Shells of well-developed 
fruits have been found to contain the bacteria (106). When relatively 

" "Slime disease" is a general term applied to the effects of Bacterium solanaceamm on a 
large number of hosts. 



298 THE PEANUT— THE UNPREDICTABLE LEGUME 

mature plants are attacked there is no evidence of an invasion of the 
fruit (23). 

When not otherwise e\'ident the infection may be detected in cross 
sections of stems and roots. Dark-brown spots are usually evident in the 
cut xylem and pith regions (143) though healthy appearing plants may 
be filled with bacteria without any discoloration of the vessels (106). 

Organism and pathogenicity. Since about 1911 Bacterium solana- 
cearum (E.F.S.) E.F.S. has seemed definitely established as the patho- 
gen of the bacterial wilt of peanuts. Inoculation tests have established that 
a typical slime disease is produced when peanuts are inoculated with B. 
solanacearum isolated from peanuts or other plants (87, 136). The nomen- 
clature of the pathogen of slime disease is not definitely established, how- 
ever, and it has been placed in four genera other than the genus Bac- 
terium. 

With a number of plants reportedly susceptible the existence of dif- 
ferent strains of the bacterium seems likely. Early observations in the 
East Indies suggested the existence of a strain equally pathogenic to pea- 
nuts, tobacco and tomatoes (23, 122) and another strain more pathogenic 
to eggplant, potatoes and local species (122). 

In the United States, B. solanacearum has been investigated most 
frequently in connection with the "Granville wilt" of tobacco, and bac- 
terial wilt of peanuts was first noted on peanuts grown in rotation with 
tobacco (47) . The bacterium from tobacco was successfully cross inocu- 
lated into peanuts. Further studies showed that numerous other species 
of cultivated plants and weeds are susceptible to the bacterium ( 131, 136) . 
In South Africa cross-inoculation tests indicated that tomatoes and only 
one variety of tobacco were partially susceptible to the bacterium attacking 
peanuts (87). These results suggest the existence of dififerent strains of 
the bacterium in the three widely separated peanut-producing areas, and 
this may explain the apparent unimportance of the slime disease of 
peanuts in the United States. 

Factors most frequently suggested as aflfecting the pathogenicity of 
B. solanacearum on peanuts are soil type, soil moisture, and rotation 
practices. The virulence of the organism on peanuts in the East Indies 
was found to be higher on more moist soils, on heavy clay soils, and on 
soils planted to peanuts for several successive years (106). Continuous 
cultivation on irrigated soils resulted in an apparent increase in infections 
in dry seasons (121). In South Africa repeated cropping to peanuts in- 
creased the severity of the disease which was apparently restricted to the 
heavier loamy soils (87) . This emphasis on soil texture and drainage sug- 



PEANUT DISEASES 299 

gests that sandy soil may be an important factor in making bacterial wilt 
relatively unimportant in the United States. 

Control. Planting of a resistant variety is the most convenient means 
of controlling the slime disease of peanuts. From selection work in the 
East Indies has come the variety "Schwarz 21" which appears to have 
considerable inherited resistance to the disease. In 1937 this variety was 
reported as resulting in considerable decrease in loss from bacterial wilt 
in that area (106). 

A few attempts have been made to control B. solanacearum by soil 
treatment. Those treatments which might be applied to peanuts offer 
little hope (42, 110). Application of sulfur to East Indies soil gave no 
beneficial results on peanuts (42) . 

The control measures recommended in addition to the use of resistant 
varieties of peanuts are : 

A. Seed treatment; the bacterium can be seed-borne (106). 

B. Planting on hght, well-drained soil (87, 106). 

C. Rotation with crops which seem to be resistant to B. solanacearum 
such as sweet potatoes, grains and certain legumes (131). 

D. Variation of the rotation to prevent building up other disease-pro- 
ducing organisms in the soil to the extent that the effects on pea- 
nuts will be more detrimental than that of B. solanacearum. 

PEANUT RUST 

Importance. Peanut rust, first described from Paraguay (28), ap- 
parently is distributed throughout South America (10). There are no 
direct indications of the past or present importance of peanut rust in 
South America, though Arthur (9) suggested that rust is sometimes a 
serious peanut disease there. 

There is not complete agreement, but it is generally indicated that 
peanut rust is serious throughout the West Indies (104). Rust was first 
reported on peanuts in this area about 1911 (134) and the peanut crop 
was reported "devastated" by rust in the Dominican Republic in 1925 
(36). 

Rust of peanuts has been reported sporadically from Florida (28, 
129). In 1941, KenKnight (74) reported peanut rust from Texas with 
seven fields of Spanish peanuts in one county infected. 

Description. The existing literature is of little use in evolving a spe- 
cific description for peanut rust. The symptoms, presumably, are typical 
for rusts with the pustules of the causal organism as the most useful diag- 
nostic characteristic. 



300 THE PEANUT— THE UNPREDICTABLE LEGUME 

The peanut rust organism is found chiefly on the undersurface of 
leaves ( 10) , where it appears, first, as necrotic flecks and later as yellow- 
ish spots on the upper surface. Spores form in typical sori rupturing the 
lower epidermis. 

While these necrotic spots do not enlarge much, the infected leaves 
soon appear as though burned or scalded (74), and premature defoliation 
results (9). It is reported that premature ripening of fruits, and under- 
developed, shriveled seeds also result from rust infection (9). 

Organism and pathogenicity. There is no agreement as to the proper 
name for the causal organism of peanut rust. Arthur, in 1925 (10) re- 
ferred it to Puccinia arachidis Speg. as it was originally described. 

According to Arthur (9) telia of this organism have been found only 
once. It may be presumed that this was in connection with the type speci- 
men collection. Pycnia are unknown, and the organism does not have an 
aecial stage. 

Peanut rust has no alternate host. The uredinial and telial stages 
are found on peanuts. 

Although not cited specifically, it is presumed that the pathogenicity 
of this organism on peanuts has been proven by artificial inoculations. 
Arthur (10) lists Arachis hypogaea as the only host. West (159) dis- 
cussing the rust in breeding plots in Florida reports it on A. nambyquarae 
Hoehne; A. prostrata Benth. and a hybrid of A. hypogaea X A. namby- 
quarae. KenKnight's report from Texas (74) indicates, indirectly, that 
selection and natural hybrids within A. hypogaea may sometimes be 
highly susceptible. 

The organism appears to be seed-borne. It appears to have been 
brought into Florida recently on seeds from Brazil (159), although the 
rust had been reported from Florida twice previously (8, 129). 

Some factors have been indicated as affecting the virulence of the 
organism. Arthur (9) concluded that peanut rust is more prevalent in wet 
seasons, with very little damage when infection is accomplished late in the 
growing season. In the West Indies the degree of infestation appears to 
depend largely on climate and condition of the soil (104). When con- 
ditions favor growth and vigor of peanuts only leaves approaching senility 
are infected. Under less favorable conditions infection is higher and 
results in death of the entire plant. 

Control. Spraying with Bordeaux mixture has been reported as in- 
creasing the yield of rust-infected peanuts in the West Indies ( 104) . In a 
3-year experiment ( 104) it was finally concluded that while two applica- 
tions of Bordeaux produced some beneficial results, it could not be said 



PEANUT DISEASES 301 

that measurable control was achieved unless more than two sprays were 
applied. Arthur (9) regarded attempts to control the rust with Bordeaux 
sprays as "not achieving much success." 

DISEASES OF APPARENT IMPORTANCE IN LOCALIZED 

AREAS 

Three peanut diseases have been reported in recent years from defi- 
nitely limited areas. It is indicated, directly or indirectly, that these 
diseases are of importance where found. It may be assumed that such 
diseases are a potential threat to other peanut producing regions. 

1. Sphaceloma scab (Brazil) 

A scab disease of peanuts caused by Sphaceloma arachidis Bitt. and 
Jenk. has been reported from Brazil with pathogenicity of the organism 
demonstrated (19). Species of Sphaceloma (Elsinoe) are associated with 
destructive anthracnoses of many plants. 

The main symptom of this type of anthracnose is the small necrotic 
or hyperplastic lesions on leaves, hence the name "scab" for the disease. 
The lesions on peanuts are found predominantly on leaves, sometimes on 
petioles and stems (19). On leaves they are found on veins as well as be- 
tween veins. 

Sphaceloma scab was reported severe on peanuts in Brazil in 1938 
with much less severe infection in 1939 and 1940 (39). Some varieties 
showed apparent resistance (39). No specific control measures have been 
recommended. 

2. Aspergillus crown rot (Queensland, Australia) 

A seedling blight or crown rot of peanuts has been described from 
Australia and an Aspergillus sp. is regarded as the pathogen (99, 100). 
The disease develops on plants from germination to maturity but is most 
important as it affects the initial stand since pre-emergence losses are 
greatest. Infection apparently takes place through lesions in the seed coat 
and spreads from cotyledons to the stem. 

When plants approaching maturity are attacked, there is a general 
wilt. Sometimes a mass pf spores of an Aspergillus sp. is found in this in- 
fected tissue. No inoculation tests appear to have been made, but it is 
assumed that this Aspergillus sp. is pathogenic. 

Observations indicate that the disease is worse under conditions of 
high soil moisture, low fertility, unfavorable soil texture, and continuous 
cropping to peanuts. Recommendations for control are: Avoidance of 
excessive seed injury, seed treatment, planting of peanuts in rotation with 
corn, small grains, or grasses (99, 100). 



302 THE PEANUT— THE UNPREDICTABLE LEGUME 

Aspergillus rot is in part a pre-emergence disease and is most serious 
in that aspect. The post-emergence aspects of Aspergillus crown rot 
strongly resembles collar rot^^ of the southeastern United States. 

3. Texas Root Rot (Southwestern United States) 

In the southwestern United States Phymatotrichum omnivorum 
(Shear) Dugg. causes a root rot of a number of plants. This root rot is 
generally regarded as the most important plant disease in that area (31). 
Peanuts have been reported attacked by this organism in Texas, Arizona 
and New Mexico with greater losses on heavier soils. In one survey in a 
Texas county, 7 of 11 peanut fields were found infected with losses of at 
least 15 percent in most fields and up to 83 percent in some fields (75). 

Fine, brownish strands of the fungus cover the roots of infected 
plants before above-ground symptoms are evident. Under moist conditions 
spore mats appear on the soil above infected roots. These mats are 2 to 12 
inches in diameter, are originally white and cottony but turn tan with 
spore formation. The fungus forms rhizomorphs and pinhead size scler- 
otia. The sclerotia are light tan, and become darker and warty with age. 
The sclerotial stage has been called Ozonium omnivorum Shear. The 
foliar response is wilting, with death occurring in a few days. The entire 
root system decays and the plant slips from the soil easily. 

It is suggested (75) that damage to peanuts by Texas root rot in- 
creased as a result of expanding peanut acreage to heavier soils as well 
as to soils known to be infected. Chester (31) suggests the following prac- 
tices for the control of Texas root rot: (A) Three- or 4-year rotations of 
susceptible crops with highly resistant crops, such as grains; (B) avoid- 
ance of susceptible perennials, such as alfalfa, and certain trees and orna- 
mentals; (C) promotion of soil organisms antagonistic to Phymatotri- 
chum omnivorum through the use of manure or other organic fertilizers ; 
(D) clean cultivation to eliminate susceptible weeds. 

DISEASES OF MINOR IMPORTANCE 

Quite a few diseases of peanuts appear to be unimportant wherever 
they occur. These diseases fall into two classes : (A) Diseases known to 
be of minor importance, and (B) diseases which cannot be definitely 
classified because they have not been extensively studied. 

All of these diseases may be important under abnormal environmental 
conditions, thus such diseases should be regarded as potential threats. 

^ See page 269 for discussion of collar rot. 



PEANUT DISEASES 303 

Phyllosticta Leafspot 

In the southeastern United States primary and other seedling leaves 
of peanuts are always infected with a leaf-spot organism. The spots differ 
from typical peanut leafspot (Ccrcospora spp.) in being smaller, more 
irregular, without definite halos, and in being found only on juvenile 
leaves. Moist chamber culture of leaves shows that a Phyllosticta sp. is as- 
sociated. This organism apparently cannot infest older leaves. It is also 
apparent that the peanut plant is not noticeably damaged by these leaf- 
spots on younger leaves. There is also a report from Burma of the occur- 
rence of a Phyllosticta on peanuts (117). 

FusARiuM Wilt or Root Rot 

Many peanut-disease surveys made in southern United States have 
listed Fusariiim wilt on peanuts. In Texas a seedling blight, apparently 
due to a Fusariiim sp., was regarded as one of several factors necessitat- 
ing replanting of several fields in 1941 (75). In Georgia in 1932 (92) it 
was reported that an early or seedling wilt caused by F. martii var 
Phaseoli Burk. depleted stands from 10 to 38 percent in some counties. 
Fusaria can be isolated from peanut seeds readily and isolations from 
"diseased peanut tissue" in North Carolina were approximately 50 per- 
cent Fusaria ( 101 ) . 

In 1932 a Fusarinin sp. was shown, by inoculation, to be the cause of a 
"destructive" wilt of peanut in Kenya, Africa (89), but since then con- 
tinuous selection has maintained sufficiently high resistance to keep up 
production (65). 

The following description of a Fusariiim wilt of peanuts is based on 
that given by Miller and Harvey (92) from Georgia: Maximum infection 
occurs at blooming. Entire plant is usually killed, but sometimes only the 
shoots. Lesions on roots at first are small, elongate, light-centered with 
darker edges. Roots eventually are girdled by enlargement of lesions. Rot 
progresses through the roots with hyphae evident in the disintegrating 
tissue. There is no plugging of xylem vessels. In advanced stages the 
taproot is rotted just below soil surface. 

The Fusariiim "wilt" of peanuts, as described, is not a typical wilt. 
The plugging or disintegration of conducting cells usually found in wilts 
has ijot been reported from peanuts. Rather the peanut disease, as noted, 
was a typical root rot. 

It is difficult to establish the pathogenicity of a Fusarium sp. The 
senior author has made numerous unsuccessful attempts to prove patho- 



304 THE PEANUT— THE UNPREDICTABLE LEGUME 

genicity of Fusaria isolated from diseased peanut roots and stems. Others 
liave verbally reported similar results. Miller and Harvey (92), in 
Georgia, in tests on a Fusarium sp. from peanuts obtained results only 
with young plants and with abrasions on roots, and a filtrate of cultures 
also induced wilting in young peanuts. 

The status of Fusarium wilt of peanuts is indefinite and its importance 
questionable. Though reported frequently from southern United States it 
has never again reached the proportionate importance attributed to it in 
Georgia in 1932 (92). The wilt in Kenya has apparently been brought 
under control by the use of selections (65). Further investigation, there- 
fore, is needed to clarify the association of the Fusaria with peanut dis- 
eases. At present only seed treatment and good cultural practices can be 
recommended for control. 

SCLEROTINIA BlIGHTS 

Species of Sclerotinia have been reported as associated with stem, 
root and pod rots of peanuts (35, 85, 146). These diseases appear to be 
relatively unimportant and primarily of mycological interest. 

According to Chu (35) and Suematu (146) two "new species" of 
Sclerotinia (S. miyabeana and 5". arachidis) were described from peanuts 
in Japan by Hanzawa in 1911. Hanzawa's report was "privately printed" 
and mycologists have regarded the publication of these species as invalid. 

According to Chu (35) the Sclerotinia blight of peanuts in Japan and 
China is primarily a stem rot, but all parts of the plant are sometimes at- 
tacked. Pods may be found containing sclerotia of the organism with 
seeds thinly coated with mycelium. Infection from spores is apparently 
through wounds except on flower petals, but hyphae from germinating 
sclerotia may invade uninjured tissue. 

Lesions produced by Sclerotinia miyabeana are reported as purplish 
brown, eventually "shade-brown" while those produced by S. arachidis 
begin brown and blacken rapidly (35). Botrytis type conidia are fre- 
quently associated with the fungus called S. arachidis but have never been 
found associated with S. miyabeana (35). 

Chu (35) reported several other hosts for these Sclerotinias including 
grasses, weeds and garden plants. 

A "wilt" of peanuts apparently caused by Sclerotinia trifoliorum 
Eriks. was reported from Argentina in 1922 (85). 5. trifoliorum is an im- 
portant stem-rotting organism of clovers, but this apparently is the only 
report of it on peanuts. As control measures it was recommended that 
affected plants be destroyed and crop rotation and cultivation to prevent 



PEANUT DISEASES 305 

excessive accumulations of soil moisture be practiced. There is the possi- 
bility that one (or both) of the Sclerotinias on peanuts reported from 
China and Japan is the same as this Sclerotinia reported from Argentina. 

BoTRYTis Late Blight 

Species of Botrytis have been observed associated with some unim- 
portant diseases of peanuts. Possibly these Botrytis spp. are conidial 
forms of Sclerotinias but no studies have been made of this aspect. 

Suematu (146) in Japan reported peanuts severely attacked by a 
Botrytis sp. during persistent wet weather, with the fungus forming 
conidia on stems and pods. Attacked pods did not mature and were 
later covered with dark sclerotia. Successful inoculation tests were re- 
ported. 

Typical Botrytis late blight of peanuts has been observed by B. B. 
Higgins in Georgia ^^. Noted on mature or overmature peanuts, the in- 
fection develops during cool damp days of early fall. Growing tips were 
attacked and covered with a grey spore mass. Sclerotia were formed on 
pegs and pods, a few of which were partially to completely decayed. 

It would appear that the parasitism of Botrytis sp. on peanuts may 
be dependent upon damp cool weather. Control methods include planting 
practices to avoid maturation during such weather. 

Ashy Stem Blight and Diplodia Blight 

In the southeastern United States older peanut plants killed by Sclero- 
tium roljsii, insects, etc. are soon overgrown by fungi. Many living plants 
approaching maturity are similarly overgrown, particularly those partially 
defoliated by leaf spot or insects. Examination usually shows that these 
fungal structures are sclerotia of Sclerotium bataticola Taub., pycnidia of 
Macrophomina phaseoli (Maubl.) Ashby, and pycnidia of a Diplodia 

sp- 

Ashy stem blight. The sclerotia of Sclerotium bataticola and pycnidia 
of Macrophomina phaseoli on peanuts give the stems an "ashy" appear- 
ance. The structures are regarded as stages of the same fungus, and this 
has been demonstrated with isolations from plants other than peanuts 
(83). 

Most references to Sclerotium bataticola on peanuts are primarily 
concerned with the seedling disease "charcoal rot"^*- Observations on a 
variety of plants indicate that ashy stem blight results from invasion of 

13 Unpublished observations. 

" See previous section on charcoal rot, page 267; also section on concealed damage, pp. 284-288 
for another aspect of i'. bataticola on peanuts. 



306 



THE PEANUT— THE UNPREDICTABLE LEGUME 




Courtesy Georgia Acirievltiiral Evpcrimcnt Station 

Figure 3. — Botrytis late blight on peanuts. 

weakened plants. The organism, while sometimes a vigorous parasite on 
seedlings, particularly at high temperatures, appears to be primarily a 
weak parasite on older or mature plants. This parasitism of 5". bataticola 
has been investigated and the various observations summarized (63). 

In regard to peanuts, the ashy stem blight needs investigation. It is 
possible that following periods of excessively high temperatures, excessive 
defoliation, or excessive insect injury it becomes an important disease re- 
sulting in death or early maturity of many plants. This insect injur)- and 
defoliations may be prevented to some extent by dusting programs. 

Diplodia blight. DipJodia sp. has been reported frequently on peanuts 
in the United States (13). It has been shown that Diplodia sp. is fre- 
quently associated with peanut seed^" and thus ma}' be seed-transmitted 
(149). A Diplodia sp. is frequently isolated from }'oung peanut plants 
with collar rot-"^" but pycnidia are generally not found on younger plants. 
Pycnidia are frequently found on stems of dead or living mature plants ; 
thus Diplodia blight is distinctly a disease of older plants. Diplodia blight 
is easily confused with ashy stem blight. Frequently pycnidia of both 

IS See section on "concealed damage," pp. 284-288. 
^* See section on "collar rot," page 269. 



PEANUT DISEASES 307 

Diplodia sp. and Macrophomina phaseoli are found on the same peanut 
plant. 

Little is known about the parasitism of Diplodia sp. on peanuts. Lack- 
ing other conclusive evidence it may be assumed that Diplodia blight 
usually develops on nearly mature plants and results in little decrease in 
yield and few deaths. The inoculum is probably soilborne. There may be 
some carryover from seed-borne inoculum or seedling infection, but such 
earl)' infected plants probably die before they reach the stage of maturity 
at which Diplodia blight develops. 

Nematodes on Peanuts 

Three types of nematodes have been reported on peanuts, but only 
the root-knot type has attracted much attention. 

Root-knot nematodes. Root knot was reported from peanuts in the 
United States in 1931 (4) and 1943 (13), but only since 1946 has it been 
given more than passing attention. Parasitic nematodes were noted on 
peanuts in South Africa in 1926 (137) but apparently were considered 
unimportant. 

Christie (33) inoculated Virginia runners with nematode populations 
from alfalfa, cotton, peanuts and sweet potatoes. After 6 weeks there was 
no development of nematodes on peanuts inoculated with sweet potato 
populations, but those inoculated with alfalfa and cotton populations 
showed nematodes in the larval stages. The peanut plants inoculated with 
the population from peanuts showed numerous egg-laying females. From 
this Christie concluded that the peanut as a host has a varying effect on 
the development of dififerent nematode races. 

Wilson (164) noted populations or strains of root-knot nematodes 
attacking peanuts readily in North Carolina, Mrginia and Alabama, and 
evidently on the increase in Alabama. A similar observation regarding 
southern Georgia has been received from J. H. Miller^^. Recently Chit- 
wood (32) placed the root-knot nematodes in the species Meloidogyne 
arenaria. 

Root knot on peanuts is very similar to root knot on other plants. 
Typical galls are produced on the taproot, lateral roots, pegs and shells. 
The symptoms are shown in figure 4. If infection occurs early the plants 
are stunted and the margins of the leaves become necrotic. 

Root knot does not seem to have been a serious disease of peanuts in 
the past. It looks as though the strain or strains of nematodes attacking 
peanuts are now on the increase in three major peanut-producing regions 

^~ Personal communication. 



308 



THE PEANUT— THE UNPREDICTABLE LEGUME 









a 

a 
o 

in 

<u 

T3 
O 



O 

a 

O 

o 
I 









PEANUT DISEASES 309 

of the United States. This disease, then, is a potentially serious disease in 
these regions. Rotation offers the only hope for large-scale control. There 
is need for research to determine host ranges of the strains attacking pea- 
nuts in order that rotation programs can be intiated. 

Nematodes and witches' -brooms on peanuts. In 1935 peanuts were 
found in Tennessee with typical witches'-brooms and the nematode 
Cephalobus elongatus cle Man. was isolated from them (5). In 1936 a 
similar witches'-broom of peanuts was found in Texas. Isolations yielded 
C. elongatus and Acrobeles crossatus Steiner. In the latter case it was 
doubted that either nematode was the cause of the witches'-broom. 

Meadow nematodes and peanuts. Nematodes of the genus Praty- 
lenchus Filipjev cause a general root destruction of many plants (138). 
Little is known of the effects of these meadow nematodes on peanut roots, 
but they do frequently attack pods, producing black spots and providing 
points of entrance for secondary invaders. Steiner (138) has indicated 
need for more work on these nematodes. This need is doubly evident for 
peanuts because of the possibility of both root and fruit damage. 

Rhisoctonia on Older Peanuts 

There are references from almost all peanut-producing regions to 
Rhizoctonia solani Kuhn on peanuts^*- While usually not stated, it ap- 
pears that the primary concern is with seedling diseases. 

In the southeastern United States many peanut plants beyond the 
seedling stage show typical dry, greyish or reddish-brown Rhizoctonia 
cankers on stems near the soil. Although some cankered stems break off 
in wind or during cultivation or dusting, few, if any, plants appear to be 
killed as a result of this cankering. At maturity numerous greyish-blue 
fruiting bodies on the "perfect" stage — Corticium solani (Prill, and De.) 
Bound and Galz. — may be found on peanut stems in contact with the 
soil. It may be that high temperatures during the growing season are the 
important factor in making R. solani of little apparent consequence on 
peanuts beyond the seedling stage. 

Possibly attacks of R. solani on the peg are an important factor in 
harvest nut losses^®. At present any theory as to R. solani and diseases 
of peanuts beyond the seedling stage is purely suppositionary. 

" See page 267 for section on seedling dry rot. 

*" See page 282 for section on soil rots of nuts and pegs. 



310 THE PEANUT^THE UNPREDICTABLE LEGUME 

DEPREDATIONS OF ANIMALS 

Animals may damage peanut plants in any stage from the planted 
seed to the mature plant. These depredations may be evident in forms 
other than the eating of leaves, seeds or nuts. The damage to the peanut 
crop caused by animals eating the mature or almost mature pods is some- 
times quite spectacular. 

Gophers (tortoises) have been noted from Florida (119) as pests of 
peanuts, and the western gopher (a rodent) was similarly noted from 
Oklahoma {77^. Everyone has observed considerable numbers of dead 
plants following attacks of moles on the root system. Skunks and wild 
turkeys display a fondness for peanut pods in the "milk" stage. There is 
nothing, however, which will indicate that any general importance can be 
attached to such depredation of animals. 

PHYSIOLOGICAL OR NONPATHOGENIC DISEASES OF 

PEANUTS 

Mineral Deficiency Syitipfoius. The chart on next page summarizes 
the known mineral-deficiency s}-mptoms on peanuts. 

Described Physiogenic Disorders. The following have been specifically 
reported as nonpathogenic diseases of peanuts : 

"Clump" or "Bunch" . A condition called "clump" or "bunch" has 
been described from India. Plants were densely clumped, with tufted and 
dwarf shoots, yellowed leaves, arrested growth and erect habit. Yield of 
affected plants was reported ( 147) as only 30 percent of normal. Poor 
soil and the use of immature seeds were thought to be responsible. No 
evidence of parasitism w as noted. It has been suggested that "clump" may 
be a phase of rosette but the matter is still indefinite. 

Nonparasitic Leafspots. A peanut leafspot characterized by some- 
what rectangular, brown to black splotches on the lower surface, with 
pin-point necrotic areas was described from Georgia in 1941 (69). The 
disorder, found on puddled clay soil, was believed to be a mineral de- 
ficiency resulting from the puddling. 

Inherited Albinism. Albinism, varying from a few chlorotic streaks in 
leaves to complete albinism of the entire plant, is a fairly common occur- 
rence in peanut fields in southern United States. This albinism has not 
been studied. The only logical explanation seems to be that it is a genetical 
condition resulting from chance cross pollination. 

Pale Dzvarf. A condition called "pale dwarf" reported from Java in 
1927 (58) was characterized by early paling and dwarfing of leaves. The 



PEANUT DISEASES 
Mineral-Deficiency Symptoms Observed on Peanuts 



311 



Deficient 
Mineral 


Peanut 
Variety 


Age of 
Plants 


Foliar Symptoms 


Reference 


Leaves 


Stems 


Nitrogen 


Virginia 
Bunch 


6 
weeks 


General chlorosis 


Reddish color 


(29) 


Phosphate 


Virginia 
Bunch 


6 

weelcs 


Fully developed 
leaves are dark green 
changing to yellow 


Reddish color 


(29) 


Potassium 


Virginia 
Bunch 


6 
weeks 


Light green changing 
to scorch areas on 
margin 


Reddish color 


(29) 


Calcium 


Virginia 
Bunch 


6 

weeks 


Brownish necrotic 
areas on fully devel- 
oped leaves over 
entire surface 


Disturbances in 
meristematic re- 
gion in late 
stages of defi- 
ficiency 


(29) 


Magne- 
sium 


Virginia 
Bunch 


6 
weeks 


First in older leaves 
a chlorosis of leaf 
margins, with entire 
leaves becoming 
chlorotic 


Lack of the red 
coloration 


(29) 


Iron 


Spanish 


6 
weeks 


Youngest leaves 
become chlorotic 




(132) 


Boron 


Virginia 
Bunch 


6 
weeks 


Brownish necrotic 
areas limited to the 
edges of the leaves 




(29) 


Zinc 


Spanish 


all 
stages 


No observed symp- 
toms 


No observed 
symptoms 


(14) 


Manga- 
nese 


Spanish 


all 
stages 


No observed symp- 
toms 


No observed 
symptoms 


(132) 


Copper 


Spanish 


all 
stages 


No observed symp- 
toms 


No observed 
symptoms 


(132) 


Sulfur 


(No repo 


rts in th< 


; literature) 







Prepared by H. S. Ward, Jr., associate botanist, Alabama Polyteclinic Institute, and through his 
courtesy. 

peanuts usually recovered. The condition was believed to be nonparasitic 
and caused by excessive heat of surface soil after planting. 

Physiological Chlorosis. Chlorosis, apparently neither inherited albi- 
nism or associated with viroses, has been reported from Somaliland ( 18) 
and attributed to unfavorable weather and soil conditions. A similar 
chlorosis has been reported from Texas as "physiological chlorosis" (75). 



312 THE PEANUT— THE UNPREDICTABLE LEGUME 

Disease-Like Results of Insects. Certain effects of insects on plants 
are sometimes difficult to distinguish from pathogenic diseases. An ex- 
ample is "peanut pouts" originally regarded as a disease of unknown 
cause. The swollen, distorted areas on leaves and young stems were 
shown by Metcalf (90) to be the result of toxins from mass-attacking 
leafhoppers. It was later pointed out that thrips injury is also sometimes 
referred to as peanut pouts (128). 

RARE OR ACCIDENTAL DISEASES 

Any crop is sometimes found attacked by fungi under "unusual" cir- 
cumstances. It is rare that such unusual diseases assume any importance, 
and they have never been regarded as important on peanuts. Only a few 
diseases of this type have attracted sufficient attention to be reported. 

1. Seedling rots caused by mold-type fungi. Seedlings of peanuts are 
sometimes killed by overgrowth of mold fungi (72). Almost always 
extenuating circumstances are obvious : The seedling has been suppressed 
or wounded by growing under a hard soil crust ; there has been exces- 
sively heavy rainfall coupled with excessively low temperatures ; or some 
other equally apparent circumstance. The fungus overgrowth is usually a 
Rhizopus sp., Penicillium sp., or Aspergillus sp. 

2. Fungus leaf spots following insect injury. Typical fungus-type leaf 
spotting sometimes develops following insect injury. For example, an 
Alternaria sp. leafspot has been reported from Virginia (11) associated 
with leaf-hopper damage. Undoubtedly these unusual leafspots are very 
unimportant in the total picture of peanut diseases. 

3. Diaporthe blight. A situation has been reported from Virginia (12) 
in which Diaporthe phaseolorum var. sojae (Lehm.) Wehm. was sus- 
pected as the initial cause of the death of peanuts. In a later study (84) 
neither the species D. phaseolorum (C. and E.) Sacc. nor the variety 
could be shown by inoculation to be pathogenic to peanuts. 

4. Anthracnose of peanuts. There are only two reports on the occur- 
rence of anthracnose fungi on peanuts. A Colletotrichum sp. was ob- 
served on peanut leaves in Uganda, Africa, in 1926 (130) and Colleto- 
trichum sp. was the most abundant fungus in a few dark-colored stem 
lesions on peanuts in Oklahoma in 1944 (78). 

MISCELLANEOUS FUNGI 

A large number of fungi have been reported from peanuts only once 
and the reports are now buried in obscurity. Host indexes list species of 
fungi on peanuts for which it is impossible or almost impossible to find the 



PEANUT DISEASES - 313 

original reference. Abstracting journals also note many fungi as "on pea- 
nuts." These fungi, which do not seem to be associated with important 
peanut disorders, are best classified as "miscellaneous." To make a de- 
tailed listing of such fungi would probably confuse rather than clarify. The 
reports on miscellaneous fungi of peanuts fall into three main classes : 

(A) Saprophytic fungi included in results of general mycological 
surveys. 

(B) Fungi suspected of being parasitic on peanuts but which have 
not yet merited or received further investigation. Examples of this would 
be the Phoma sp. noted on rotting peanut stems in Alabama in 1914 ( 168) 
and the V erticillium sp. found in wilting peanuts in Australia in 1945 
(99). 

(C) Fungi described as new species. For example: Ascochyta 
arachidis Woron. listed on "dying peanut leaves" in the Caucasus in 
1924 (173). 

SELECTED REFERENCES 

When appearing in the following references, T. T. means that the title of the 
cited article has been translated into English and is given in abstracted form; 
R. A. M. means that a brief abstract of the article is available in the British ab- 
stracting journal REVIEW OF APPLIED MYCOLOGY on pages cited. 

(1) Alstatt, George E. 

1944. Sclerotium rolfsii on peanuts in texas. U. S. Dept. Agr. Plant Dis. 
Rpt. 28:1097. 

(2) Anon. 

1920. peanuts. U. S. Dept. Agr. Plant Dis. Bill. 4:122. 

(3) 

1925. ROSETTE DISEASE OF PEANUTS. Union S. Africa, Dept. Agr. Jour. 
11:10-11. 

(4) 

1931. ROOT KNOT ON PEANUTS. U. S. Dept. Agr. Plant Dis. Rpt. 15:145. 

(5) 

1935. CEPHALOBUS ASSOCIATED WITH A PEANUT DISEASE. U. S. Dept. Agr. 

Plant Dis. Rpt. 19:254. 

(6) 

1941. ANNUAL REPORT OF THE GAMBIA DEPARTMENT OF AGRICULTURE FOR 
YEAR ENDING 31 MAY, 1941, 8 pp. (R.A.M. 21:65). 

(7) 

1943. (t.t.) REPORT FOR YEARS 1940 AND 1941. Pub. Inst. Nat. Etud. Agron., 
Congo Beige, 152 pp., (R.A.M. 23:432). 

(8) Arthur, J. C. 

1920. TWO DESTRUCTIVE RUSTS READY TO INVADE THE UNITED STATES. Science 

N. S. 51:246-247. 

(9) ..:- 

1929. THE PLANT RUSTS. 446 pp. John Wiley and Sons, New York. 



314 THE PEANUT— THE UNPREDICTABLE LEGUME 

(10) Arthur, J. C. 

1907-193L UREDINIALES. North American Flora 7:83-969. (P. 484). 
(U) Atkinson, R. E. 

1943. PEANUT DISEASES IN NORTH CAROLINA AND SOUTH CAROLINA. U. S. 

Dept. Agr. PI. Dis. Rpt. 27:501-503. 

(12) 

1944. SOUTHERN BLIGHT AND DiapoHhe ON PEANUTS IN VIRGINIA. U. S. Dept. 

Agr. Plant Dis. Rpt. 28:1096-1097. 
(13) 

1944. DISEASES OF PEANUTS AND SOYBEANS IN THE CAROLINAS IN 1943. 

U. S. Depr. Agr. Plant Dis. Rpt. Suppl. 148:254-259. 

(14) Barnette, R. M., Camp, J. P., Warner, J. D. and Gall, O. E. 

1936. the USE OF zinc sulphate under CORN AND OTHER FIELD CROPS. Fla 

Agr. Expt. Sta. Bui. 292. 

(15) Beattie, W. R. 

1909. peanuts. U. S. Dept. of Agr. Farmers' Bui. 356, 40 pp. 

(16) 

1911. THE PEANUT. U. S. Dept. of Agr. Farmers' Bui. 431. 39 pp. 

(17) Bertus, L. S. 

1927. A SCLEROTIAL DISEASE OF GROUNDNUTS CAUSED BY Sclerottum rolfsH. 

SACC. Yearbook, Dept. Agr., Ceylon. 1927. 41-43. (R.A.M. 6:389- 
390). 

(18) BiGI, F. AND ClFERRI, R. 

1938. (t.T.) GROUNDNUT ROSETTE REPORTED FROM ITALIAN SOMALILAND. 

Agricultura Colon. 32:105-113. (R.A.M. 17:725). 

(19) BiTANCOURT, A. A. AND JENKINS, A. E. 

1940. (t.T.) NEW SPECIES OF Elsinoe and Sphaceloma on hosts of economic 
IMPORTANCE. Arq. Inst. Biol., S. Paulo 11:45-58. (R.A.M. 20:427). 

(20) Bledsoe, R. W., Harris, H. C. and Clark, F. 

1945. THE importance of peanuts left in the soil in interpretation of 

increase in yield due to sulfur treatments. Jour. Amer. Sor. 
Agron. 37:689-695. 

(21) Bond, R. C. 

1946. peanuts. Fla. Expt. Sta. Ann. Rpt. 1946. 139. 

(22) Bottomley, a. M. 

1940. SCLEROTIUM OR ROOT ROT DISEASE OF GROUNDNUTS. Fnig. S. Afr. 

15:189-191, 194. (R.A.M. 19:579). 

(23) Breda de Hahn, J. van. 

1906. RAPPORT OVER ziEKTE IN DEN AANPLANT \Afi Arachis hypogaca (katjang 

HOLLE) in DE AFDEELINGEN KOENINGAN IN CHERIBON DER RESIDENTIE 

cheribon. October 1905. Teijsmannia, Batavia, 17:52-63. (cited in 
Bacteria in Relation to Plant Diseases 3:153). 

(24) Brooks, A. J. 

1927. rosette disease of groundnuts. Dept. Agr. Ann. Rpt. Gambia. 

1926-1927. 53 pp. (R.A.M. 7:15). 

(25) 

1928. rosette disease investigations. Dept. Agr. Ann. Rpt. Gambia. 

1927-1928. 54 pp. (R.A.M. 8:18). 



PEANUT DISEASES 315 

(26) Brooks, A. J. 

1931. PEANUT DISEASES. Annual Rept. Dept. Agri. Gambia. 1930-1931. 51 p. 

(R.A.M. 11.27). 

(27) 

1932. ROSETTE INVESTIGATIONS. Ann. Rpt. Dept. Agr. Gambia. 1931-1932. 

18 pp. (R.A.M. 11:697). 

(28) Burger, O. F. 

1921. PEANUT RUST CAUSED BY Puccinia {Uredo) arachidis. U. S. Dept. Agr. 
Plant Dis. Bui. 5:88. 

(29) BURKHART, L. AND CoLLINS, E. R. 

1942. MINERAL NUTRIENTS IN PEANUT PLANT GROWTH. PrOC. Soil Sci. SoC. 

Amer. 6:272-280. 

(30) Carver, W. A. and Hull, Fred H. 

1946. peanut improvement. Fla. Agr. Exp. Sta. Rpt. 1945-1946. 36. 

(31) Chester, K. W. 

1947. nature AND prevention of plant diseases. 2nd Edition. 525 pp. 

The Blakiston Co., Philadelphia. 

(32) Chitwood, B. G. 

1949. "root-knot nematodes", part i. a revision of the genus Meloi- 

dogyne goeldii 1887. Proc. Hel. Soc. Washington 16:90-104. 
(iS) Christie, J. R. 

1946. host-parasite relationships of the root-knot nematode, Hetero- 
dera marioni. ii. some effects of the host on the parasite. 
Phytopath. 36:340-352. 

(34) Christoff, a. and Christova, E. 

1936 (t.t.) some new plant diseases for Bulgaria (3rd contrib.) 
Bui. Soc. Bot. Bulgarie 7:7-22. (R.A.M. 15:745-746). 

(35) Chu, V. M. 

1933. notes on the presence of Sclerotinia miyabeana in china, and 

comparison of this FUNGUS WITH ScleroUnia arachidis. 1932. Year- 
book Bur. of Entom. Hangchow, China: 1-58. (R.A.M. 13:615-616). 

(36) Ciferri, R. 

1926. (t.t.) report on plant pathology and agricultural entomology. 
1st Ann. Rpt. Agron. Sta. of the College of Agriculture de Haina 
Dominicans Republic. 27-36. (R.A.M. 5:599-600). 

(37) Cooper, W. E. 

1950. TWO virus diseases of peanuts. (Abstr.) Phytopath. 40:6. 

(38) Costa, A. S. 

1941. (t.t.) a virus disease of the groundnut (Arachis hypogaea L.) 
ringspot. Biologico 7:249-251. (R.A.M. 21:119-120). 

(39) and deSouza, O. F. 

1941. (t.t.) note on groundnut scab. Biologico 7:347-349. (R.A.M. 21 :239). 

(40) Crandall, B. S. 

1 945. NURSERY ROOT AND COLLAR ROT OF CICHONA AND ROOT ROT OF CANAVALIA 

CAUSED BY Sclerotium rolfsii. U. S. Dept. Agr. Plant Dis. Rpt. 29: 
536-537. 

(41) Crosier, W. F. 

1943. SEED-BORNE MICROORGANISMS. 62nd Ann. Rept. N. y. (Geneva) Expt. 
Sta. 56-57. 



316 THE PEANUT— THE UNPREDICTABLE LEGUME 

(42) DE Jong, A. W. K. 

1913. (t.t.) studies on bacterial disease of the peanut. Dept. Landb. 

Nijv en Handel, Med. Agr. Chem. Lab. 3:56-59. (E.S.R. 29:448). 

(43) DuNLAP, A. A. 

1943. PEANUT SEED TREATMENT. Texas Agr. Expt. Sta. Prog. Rpt. 833. 

(44) Evans, M. M. and Poole, R. F. 

1938. some parasitic fungi harbored by peanut seed stocks. (abstr.) 
Jour. Elisha Mitchell Sci. Soc. 54:190-191. 

(45) Fenne, S. B. 

1946. report of the regional peanut seed treatment tests conducted 
IN 1945. U. S. Dept. Agr. Plant Dis. Rpt. 30:159-161. 
(46) 

1946. REPORT OF THE REGIONAL PEANUT SEED TREATMENT TESTS CONDUCTED 

IN 1946. U. S. Dept. Agr. Plant Dis. Rpt. 30:468-470. 

(47) Fulton, H. R. and Winston, J. R. 

1914. A disease of the PEANUT CAUSED BY Bacteruim solanacearum. Bienn. 

Rpt. 1913-14 N. C. Expt. Sta. 43-47. 

(48) Garren, K. H. and Higgins, B. B. 

1947. FUNGI associated with runner peanut seeds and their relation 

TO concealed damage. Phytopath. 37:512-522. 

(49) AND Futral, J. G. 

1947. blue-black discoloration of Spanish peanuts. Phytopath. 37:669- 
679. 

(50) Georgia Experiment Station. 

1944. seed type, seed treatment and spacing for peanuts. Ga. Agr. 

Expt. Sta. Ann. Rpt. 56:54-55. 
(51) 

1946. PEANUT SEED TREATMENT. Ga. Agr. Exp. Sta. Ann. Rpt. 58:70-71. 

(52) 

1947. PEANUT INVESTIGATIONS. Ga. Agr. Expt. Sta. Ann. Rpt. 59:79. 

(53) Georgia Coastal Plain Experiment Station. 

1946. PEANUT seed treatment. Ga. Coastal Plains Expt. Sta. Ann. Rpt. 

26:18-19. 

(54) Greulach, V. A. and Mohr, H. C. 

1947. greenhouse experiments with the southern blight disease of 

peanuts. Texas Agr. Expt. Sta. Prog. Rpt. 1097. 

(55) Handy, R. B. 

1896. peanuts: culture and uses. U. S. Dept. Agr. Farmers' Bui. 25. 24 pp. 

(56) Hansford, C. G. 

1936. annual report of mycologist, 1934. Ann. Rpt. Uganda Dept. Agr. 
1934. 73-88. (R.A.M. 15:426-427). 

(57) Harris, H. C. 

1946. nutrition of the peanut. Fla. Agr. Expt. Sta. Rpt. for 1945-1946. 46. 

(58) Hartley, Carl. 

1927. pale dwarf disease of peanuts {Arachis hypogaea). Phytopath. 
17:217-225. 

(59) Hayes, R. T. 

1932. groundnut rosette disease in the Gambia. Trop. Agr. 9:211-217. 
(R.A.M. 12:5-6). 



PEANUT DISEASES 317 

(60) HiGGiNS, B. B. 

1927. PHYSIOLOGY AND PARASITISM OF Sclerotium Tolfsu SACC. Phytopath. 
17:417-448. 

(61) 

1941. PEANUT BREEDING AND CHARACTERISTICS OF SOME NEW STRAINS. Ga. 

Agr. Expt. Sta. Bui. 213:3-11. 

(62) 

1935. BREEDING PEANUTS FOR DISEASE RESISTANCE. (Abstr.). Phytopath. 25: 

971-972. 

(63) HoFFMASTER, D. E., McLaughlin, J. H., Ray, W. Winfred and Chester, 

K. Starr. 
1943. THE problem of dry rot caused by Macrophomina phaseoli (Sclero- 
tium bataticola). (Abstr.) Phytopath. 33:1113-1114. 

(64) Hopkins, J. C. F. 

1945. the importance of seed disinfection of groundnuts. Rhodesia 

Agr. Jour. 42:432-433. (R.A.M. 25:199). 

(65) Humphrey, N. 

1942. A NOTE on groundnut selection work. E. Africa Agr. Jour. 7: 

220-221. (R.A.M. 21:439). 

(66) Hunt, N. Rex. 

1946. destructive plant diseases not yet established in north AMERICA. 

Bot. Rev. 12:593-627. 

(67) IVANOFF, S. S. 

1947. EFFECT of PRE-SOAKING UNSHELLED PEANUTS ON FUNGOUS CONTROL, 

GERMINATION, AND EMERGENCE. (Abstr.) Phytopath. 37:433-434. 

(68) Jenkins, W. A. 

1938. TWO FUNGI CAUSING LEAF SPOT ON PEANUTS. Jour. Agr. Res. 56:317-332. 

(69) 

1941. AN APPARENTLY UNDESCRIBED DISEASE OF THE PEANUT (Arochis hy- 

pogaea). Phytopath. 31:948-951. 

(70) 

1948. ROOT-ROT COMPLEX OF TOBACCO AND SMALL GRAINS IN VIRGINIA. (Abstr.) 

Phytopath. 38:14-15. 

(71) Jensen, J. S. 

1948. Personal communication, 28 May. 

(72) Jochems, S. C. J. 

1926. (t.t.) Aspergillus niger on groundnuts. Indische. Cult. (Teysmannia) 
11:325-326. (R.A.M. 5:712-713). 

(73) KenKnight, G. 

tentative recommendations for increasing peanut production 
AND DISEASE CONTROL. Texas Expt. Sta. Pop. Series Leaflet 453. 
(Undated mimeo.) 



(74) 
(75) 



1941. NOTES ON PEANUT DISEASES AND RUST IN CERTAIN TEXAS COUNTIES 

IN 1941. U. S. Dept. Agr. Plant Dis. Rpt. 25:587-588. 



1942. PEANUT DISEASES IN CERTAIN SOUTH TEXAS COUNTIES IN 1942. U. S. 

Dept. Agr. Plant Dis. Rpt. 26:499-501. 



318 THE PEANUT— THE UNPREDICTABLE LEGUME 

(76) KenKnight, G., Harrison, A. L. and Dunlap, A. A. 

1943. SULFUR and other fungicides for control of peanut diseases. 
Texas Agr. Expt. Sta. Ann. Rpt. 55 and 56:37. 

(77) Larsh, H. M. 

1943. PEANUT DISEASES IN OKLAHOMA AND ARKANSAS. U. S. Dept. Agr. 

Plant Dis. Rpt. 27:506. 

(78) 

1944. PEANUT DISEASES IN OKLAHOMA. U. S. Dept. Agr. Plant Dis. Rpt. 

28:1015, 1097. 

(79) 

1944. SUMMARY OF PLANT DISEASES IN OKLAHOMA, 1943. U. S. Dept. Agr. 

Plant Dis. Rpt. Suppl. 149:325. 

(80) Larter, L. N. H. 

1941. report OF the plant pathologist. Rpt. Dept. Sci. Agr. Jamaica. 
1940-1941:13-14. (R.A.M. 21:241-242). 

(81) Line, C. W. 

1926. work connected with insect and fungus pests AND THEIR control. 
Ann. Rpt. Dept. Agr. Gambia, 1925. 52 pp. (R.A.M. 6:17-18). 

(82) Lipscomb, R. W. 

1946. peanuts. Fla. Expt. Sta. Ann. Rpt. for 1945-1946. 145. 

(83) LUTTRELL, E. S. 

1946. a pycnidial strain of Macrophomina phaesoli. Phytopalh. 36:978-980. 

(84) — 

1947. Diaporthe phaseolorum var. sojae on crop plants. Phytopath. 37: 

445-465. 

(85) Marchionatto, J. B. 

1922. (t.t.) peanut wilt in Argentina. Rev. Facult. Agron. La Plata 
3:65-67. (E.S.R. 54:450). 

(86) Maublanch, a. 

1924. (t.t.) diseases of the groundnut. Agron. Colon. 10:1-12. (R.A.M. 
3:567). 

(87) McClean, a. p. D. 

1930. THE bacterial wilt disease of peanuts (Arachis hypogaea l.). 

S. Africa Dept. Agr. Sci. Bui. 87. 14 pp. (R.A.M. 9:698). 

(88) McClintock, J. A. 

1917. peanut wilt caused by Sclero'.ium rolfsii. Jour. Agr. Res. 8:441-448. 

(89) McDonald, J. 

1933. ANNUAL report OF THE SENIOR MYCOLOGIST FOR 1932. Ann. Rpt. Dept. 

Agr. Kenya. 1932:124-134. (R.A.M. 13:217^. 

(90) Metcalf, Z. p. 

1937. PEANUT "pouts". Science 86:374. 

(91) Miller, J. H. 

1931. plant disease survey of peanuts in GEORGIA. U. S. Dept. Agr. 

Plant Dis. Rpt. 15:167-170. 

(92) AND Harvey, H. W. 

1932. PEANUT WILT IN GEORGIA. Phytopath. 22:371-383. 

(93) Miller, L. I. 

1949. CULTURAL & parasitic r.\ces of Cercospora arachidicola and Cercospora 
personata. (Abstr.) Phytopath. 39:15. 



PEANUT DISEASES 319 

(94) Miller, L. I. 

1946. PEANUT LEAFSPOT CONTROL. Va. Agr. Expt. Sta. Tech. Bui. 104. 
(9.'5) Miller, P. R. 

1931. PEANUT DISEASE SURVEY OF VIRGINIA AND NORTH CAROLINA. U. S. 

Dept. Agr. Plant Dis. Rpt. 15:170-173. 
(96) 

1932. PEANUT FACTORY SURVEY IN VIRGINIA. U. S. Dept. Agr. Plant Dis. Rpt. 

16:24. 

(97) 

1932. PEANUT DISEASE SURVEY OF GEORGIA. U. S. Dept. Agr. Plant Dis. Rpt. 
16:163. 

(98) Moore, W. D. 

1931. peanut diseases in virginia, north carolina, south carolina, 
GEORGIA, AND ALABAMA. U. S. Dept. Agr. Plant Dis. Rpt. 15:163-170, 

(99) MoRwooD, R. B. 

1945. PEANUT DISEASES. Queensland Agr. Jour. 61 :266-271. (R.A.M. 25:248). 

(100) 

1946. PEANUTCROWNROT. Queensland Agr. Jour. 63:18-19. (R.A.M. 26:180). 

(101) North Carolina Experiment Station. 

1941. CAUSE AND control OF PEANUT DECAY BEING INVESTIGATED. Research 

and Farming (N. C. Agr. Exp. Sta. Ann. Rpt.) 1941:32. 

(102) 

1941. SEED TREATMENT IMPROVES PEANUT EMERGENCE. Research and Farm- 

ing (N. C. Agr. Expt. Sta. Ann. Rpt.) 1941. 32. 

(103) 

1943. TREATING PEANUT SEED WITH DIFFERENT MATERIALS. Research and 
Farming (N. C. Agr. Expt. Sta. Ann. Rpt.) 1943. 47-51. 

(104) NOWELL, W. 

1915. SPRAYING PEANUTS FOR LEAF RUST. Agr. News (Barbados) 14:350. 
(E.S.R. 34:746). 

(105) NUSBAUM, C. J. 

1943. PEANUT SEED TREATMENT. S. C. Agr. Exp. Sta. Ann. Rpt. 56:159-160. 

(106) Palm, B. T. 

1922. (t.t.) gummosis in Arachis hypogaea. Dept. Landb. Niju en Handel, 
Meded. Inst. Plantenziekten 52:41. (E.S.R. 49:246-247). 

(107) Panse, E. 

1937. (t.t.) curl disease (rosette, mosaic) of groundnuts. Tropenpflanzer 

40:218-220. (R.A.M. 16:653). 

(108) Pinkard, J. A. 

1942. diseases of soybeans and peanuts in MISSISSIPPI. U. S. Dept. Agr. 

Plant Dis. Rpt. 26:472-473. 

(109) Pole-Evans, I. B. 

1938. ANN. rpt. div. plant industry, 1937-1938. Farming in South Africa 

13:519-538. (R.A.M. 18:437-438). 

(110) Poole, R. F. 

1936. FURTHER studies ON THE EFFECT OF SOIL TREATMENT WITH CHEMICALS 

FOR THE CONTROL OF Bacterium solanacearum. N. C. Agr. Expt. Sta. 
Ann. Rpt. 59:34-35. 



320 THE PEANUT— THE UNPREDICTABLE LEGUME 

(111) Poole, R. F. 

1938. peanut studies. some studies of causes of root rot of peanuts. 
N. C. Agr. Expt. Sta. Ann. Rpt. 61:36-38. 

(112) PORTERES, R. AND LeGLEU, R. 

1937. (T.T.) GROUNDNUT ROSETTE. PRESENT KNOWLEDGE, RELATIONSHIP WITH 
THE SOWING DATE IN THE DISTRICT OF BAOULE-NORD, AND PROPHY- 
LACTIC METHODS TO BE APPLIED. Ann. Agr. Afr. Occ. 1:332-355. 
(R.A.M. 17:581-582). 

(113) Prince, A. E. 

1944. DISEASES OF PEANUTS IN NORTH CAROLINA. U. S. Dept. Agr. Plant 

Dis. Rpt. 28:1080-1081. 



(114) 

1945. FUNGI ISOLATED FROM PEANUTS COLLECTED IN SOUTH CAROLINA IN 

1944. U. S. Dept. Agr. Plant Dis. Rpt. 29:367-368. 

(115) Reichert, I. AND Chorin, M. 

1942. (t.t.) the high MORTALITY OF GROUNDNUTS IN 1941. Hassadeh. 22: 
197-199. (R.A.M. 26:181). 

(116) Reyes, G. M. 

1937. SCLEROTIAL wilt of peanuts with special REFERENCE TO VARIETAL 

RESISTANCE. Phil. Jour. Agr. 8:245-287. (R.A.M. 17:290-291). 

(117) Rhind, D. 

1924. report of the mycologist, burma, period ending 30 june, 1924. 
Rangoon Supdt., Govt. Printing & Stationery, Burma, 6 pp. 
(R.A.M. 4:258-260). 

(118) Rhoads, Arthur £. 

]944. summary of observation on plant diseases in FLORIDA DURING 
THE EMERGENCY OF PLANT DISEASE PROJECT SURVEY, JULY 25 TO 

DECEMBER 31, 1943. U. S. Dept. Agr. Plant Dis. Rpt. Suppl. 148:269. 



(119) 

1943. PEANUT DISEASES IN FLORIDA. U. S. Dept. Agr. Plant Dis. Rpt. 
27:504-505. 

(120) Savelescu, T., Sandu-Ville, C., Rayss, T. and Alexandri, V. 

1934. (t.t.) phytosanitary conditions in Rumania during the years 
1932-1933. Inst. Cere. Agron. al Romaniei 12. 93 pp. (R.A.M. 
14:214-215). 

(121) Schwarz, M. B. 

1927. (t.t.) preliminary results of a crop rotation test extending 

OVER several years ON RICE SOIL IN CONNECTION WITH SLIME 

disease {Bacterium solanacearum) investigations in Arachis hy- 
pogaea. Korte Meded. Inst. Voor Plantenziekten 3:11. (R.A.M. 
6:391). 

(122) : — and Hartley, C. 

1926. (t.t.) the INFLUENCE OF THE PRECEDING CROP ON THE OCCURRENCE 

OF SLIME DISEASE {Bacterium solanacearum) in Arachis hypogaea 
AND SOME OTHER PLANTS. Meded. Inst. Voor Plantenziekten 71 :37. 
(R.A.M. 6:390-391). 

(123) Shaw, Luther. 

1936. root rot ON PEANUTS IN NORTH CAROLINA IN 1936. U. S. Dept. 

.'Kgr. Plant Dis. Rpt. 20:348-349. . - 



PEANUT DISEASES 321 

(124) Shaw, Luther 

1943. PEANUT SEED TREATMENT. N. C. Agr. Ext. War Series Bui. 18. 



(125) - 

1943. ACREAGE OF PEANUTS AND DISEASE LOSSES IN 1942. U. S. Dept. Agr. 

Plant Dis. Rpt. 27:138-139. 

(126) , AND Herbert, T. T. 

1942. PEANUT DISEASES IN NORTH CAROLINA IN 1941. U. S. Dept. Agr. 

Plant Dis. Rpt. 26:109. 

(127) AND Speairs, R. K. 

1943. PEANUT DISEASES. U. S. Dept. Agr. Plant Dis. Rpt. 27:490. 

(128) Shear, G. M. and Miller, L. I. 

1941. thrip injury on peanut seedlings. U. S. Dept. Agr. Plant Dis. 
Rpt. 25:470-474. 

(129) Sherbakoff, C. D. 

1921. peanut rust caused by Uredo arachidis. U. S. Dept. Agr. Plant 
Dis. Bui. 5:50-51. 

(130) Small, W. 

1926. on the occurrences of a species of Colletotrichum. Trans. Brit. 
Mycol. Soc. 11:112-137. (R.A.M. 6:57-58). 

(131) Smith, T. E. 

1939. host range studies with bacterium solanacearum. Jour. Agr. 
Res. 59:429-440. 

(132) SoMMER, Anna L. 

1949. Personal communication. 

(133) Soriano, S. 

1932. (t.t.) a note on some plant diseases caused by "viruses" in the 
argentine republic. Physis (Rev. Soc. Argentina Cien. Nat.) 
11:87-90. (R.A.M. 13:317)." 

(134) South, F. W. 

1911. fungus diseases of groundnuts in the west indies. West Indian 
Bui. 11:157-160. 

(135) SOYER, D. 

1939. (t.t.) groundnut rosette, researches on the possible vectors of 
the disease. Publ. Inst. Nat. Etud. Agron. Congo. Beige Ser. 
Sci. 21:23. (R.A.M. 19:386). 

(136) Stanford, E. E. and Wolf, F. A. 

1917. studies on Bacterium solanacearum. Phytopath. 7:155-165. 

(137) Steiner, G. 

1926. parasitic nemas on peanuts in south AFRICA. Centbl. Bakt. 2 Abt., 
67:351-365. (E.S.R. 57:749). 

(138) 

1945. MEADOW nematodes as the cause of root destruction. Phytopath. 
35:935-937. 

(139) Stone, G. M. and Wilson, C. 

1944. rots of runner peanuts in southeastern ALABAMA. U. S. Dept. 

Agr. Plant Dis. Rpt. 28:1079-1080. 

(140) AND Seal, J. L. 

1944. peanut diseases observed in Alabama in 1943. U. S. Dept. Agr. 
Plant Dis. Rpt. Suppl. 148:279-280. 



322 THE PEANUT— THE UNPREDICTABLE LEGUME 

(141) Storey, H. H. 

1932. REFT. OF THE PLANT PATHOLOGIST. Ann. Rpt. E. Africa Res. Sta. 
4:8-13. (R.A.M. 12:143). 

(142) 



1935. VIRUS DISEASES OF EAST AFRICAN PLANTS. III. ROSETTE DISEASE OF 

GROUNDNUT. E. Africa Agr. Jour. 1:206-211. (R.A.M. 15:277). 

(143) AND BOTTOMLEY, A. M. 

1925. TRANSMISSION OF A ROSETTE DISEASE OF THE GROUNDNUT. Nature 

116:97-98. (R.A.M. 4:648-649). 

(144) 



1928. THE ROSETTE DISEASE OF GROUNDNUTS. Ann. App. Biol. 15:26-45. 
(R.A.M. 7:487). 

(145) Su, M. T. 

1938. REPORT OF THE MYCOLOGIST, BURMA, YEAR ENDING 31 MARCH, 1938. 

10 pp. (R.A.M. 18:155-156). 

(146) SUEMATU, N. 

1924. (t.t.) a botrytis disease of peanuts. Jap. Jour. Bot. Trans, and 
Abstrs. 2 :35-39. 

(147) Sundararaman, S. 

1927-1930. administrative reports of the government mycologist 
coimbatore. Reports Dept. Agr. Madras. (R.A.M. 8:17; 8:88; 
9:87; 10:360). 

(148) Taubenhaus, J. J. 

1936. witches'-broom of peanuts. Texas Agr. Expt. Sta. Ann. Rpt. 49: 

112-113. 

(149) and Ezekiel, W. N. 

1932. seed transmission of peanut diseases. Texas Agr. Expt. Sta. Ann. 
Rpt. 45:77. 

(150) Taylor, C. F. 

1944. emergency plant disease survey in Virginia — 1943. U. S. 
Dept. Agr. Plant Dis. Rpt. Suppl. 148:233-239. 

(151) Texas Experiment Station. 

1941. PEANUT diseases. Texas Agr. Expt. Sta. Ann. Rpt. 54:70-71. 

(152) Thomas, K. M. 

1941. detailed administration report of the government mycologist 
1940-1941. Rpt. Dept. Agr. Madras, 1940-1941. 53-74. (R.A.M. 
21:362-364). 

(153) TiSDALE, W. B. 

1945. TREAT PEANUT SEEDS FOR BETTER STANDS. Fla. Agr. Expt. Sta. Press 

Bui. 610. 

(154) VAN DER GOOT, P. 

1937. (t.t.) DISEASES AND PESTS OF CULTIVATED CROPS IN THE DUTCH EAST 

INDIES IN 1936. Meded. Inst. Plantziekten. Batavia 89: 104 pp. 
(R.A.M. 17:161-163). 

(155) Vaughan, E. K. 

1944. PEANUT SEED TREATMENT IN VIRGINIA 1944. U. S. Dept. Agr. Plant 
Dis. Rpt. 28:672-675. 

(156) Wallace, R. W. 

1946. PEANUTS. Fla. Expt. Sta. Ann. Rpt. for 1945-1946. 142. 



PEANUT DISEASES 323 

(157) Watkins, G. M. 

1943. PEANUT DISEASES IN TEXAS. U. S. Dcpt. Agr. Plant Dis. Rpt. 27: 
505-506. 

(158) Weiss, F. 

1945. viruses described primarily on leguminous vegetable and 
FORAGE CROPS. U. S. Dept. Agr. Plant Dis. Rpt. Suppl. 154:31-80. 

(159) West, E. 

1931. PEANUT RUST, FLORIDA. U. S. Dept. Agr. Plant Dis. Rpt. 15:5-6. 

(160) 

1947. Sderotium rolfsii sAcc. and its perfect stage on climbing fig. 
Phytopath. 37:67-69. 

(161) Wilson, Coyt. 

1947. A SURVEY of the fungi associated with PEG and seed ROTS OF 

PEANUTS IN southern ALABAMA. (Abstr.) Phytopatli. 37:24. 
(162) 

(163) 



1947. concealed damage of peanuts in Alabama. Phytopath. 37:657-668. 



1948. seed treatments for peanuts. Ala. Agr. Expt. Sta. Leaflet (Revised) 
23. 4 pp. 

(164) 

1948. root-knot nematodes on peanuts in Alabama. U. S. Dept. Agr. 

Plant Dis. Rpt. 32:443. 

(165) AND Arant, F. S. 

1949. control of insects and diseases of peanuts. Ala. Agr. Expt. Sta. 

Leaflet 27. 

(166) AND Wilson, J. P. 

1945. field studies on the relationship between the method of curing 

AND the development OF CONCEALED DAMAGE IN RUNNER PEANUTS. 

U. S. Dept. Agr. Plant Dis. Rpt. 29:61-63. 

(167) WiNGARD, S. A. AND BaTTEN, E. T. 

1945. TREAT SEED PEANUTS FOR PROFIT. Va. Agr. Expt. Sta. Bui. 382. 

(168) Wolf, F. A. 

1914. LEAF SPOT AND SOME FRUIT ROTS OF PEANUTS. Ala. Coll. Sta. Bul. 

180:127-147. 

(169) WOODROOF, J. C. AND Leahy, J. F. 

1940. MICROSCOPICAL STUDIES OF PEANUTS WITH REFERENCE TO PROCESSING. 

Ga. Agr. Expt. Sta. Bul. 205. 39 pp. 

(170) -, Cecil, S. R. and Thompson, Helen H. 

1945. the effect of moisture on peanuts and PEANUT PRODUCTS. Ga. 

Agr. Expt. Sta. Bul. 241. 23 pp. 

(171) WooDROOF, Naomi C. 

1933. TWO LEAF SPOTS OF THE PEANUT {AracMs hypogaea l.) Phytopath. 
23:627-640. 
(172) , Cole, J. R. and Hunter, J. H. 

1944. LEAFSPOT CONTROL FOR INCREASED PEANUT YIELDS. Ga. Agr. Expt. 

Sta. Cir. 145:11 pp. 

(173) WORONICHIN, N. N. 

1924. (T.T.) NEW SPECIES OF FUNGI FROM THE CAUCASUS. III. Not. Syst. ex 

Inst: Crypt. Hort. Bot. Repub. Ross. 3:31-32. (R.A.M. 4:245). 



324 THE PEANUT— THE UNPREDICTABLE LEGUME 

a74) Yu, T. F. 

1939. A LIST OF PLANT viROSES OBSERVED IN CHINA. Phytopath. 29:459-461. 
(175) Zimmerman, A. 

1907. (t.t.) a disease of peanuts. Pflanzer 3:129-133. (E.S.R. 19:448). 



INDEX 



Ackerman, A. J., 226, 250 

Acosta, Jose de, 21, 25 

acreage, 4-S, 9-13 

Ainslie, G. C, 256 

Alam, Zafar, 119 

albinism, 310 

Albrecht, H. R., 115, 132, 167, 172, 195, 

209 
Alden, C. H., 215, 251 
Alexandri, V., 320 
Allen, N., 259 
Allison, R. v., 106, 116 
almond moti, 245, 246 
Alstatt, George E., 313 
Anderson, Donald B., 119 
Anderson, L. D., 251 
Anderson, W. H., 237, 242, 250 
animal depredations, 310 
anthracnose, 312 

Anticarsia gemmatilis, 198, 210-216 
App, B. A., 261 
Arachis hypogaea, early mention of, 18- 

19; systematic position of, 59-60; 

varieties of, 60-70 
Arachis Virus /, 295 
Arant, Frank Selman, 210-250, 251, 260, 

276, 323 
armyworm, see fall armyworm 
Arnon, D. I., 118, 167 
Arthur, J. C., 299, 300, 301, 313-314 
ashy stem blight, 267, 305-307 
Aspergillus, 264, 270, 283, 287, 301-302, 

312 
Atkinson, R. E., 314 
Aull, G. H., 124, 168 
Azemard, 251 

Back, E. A., 251 

bacterial wilt, see wilt 

Bacterium solanacearum, 80, 297-299 

Badami, V. K., 23, 25, 34, 51, 52, 73, 74, 

77, 78, 80, 83 
Bailey, W. K., 116 
balance, nutritional, 113-114 
Ball, E. D., 226, 251 
Banerji, I., 54, 83 
Barber, G. W., 222, 251, 257 
Barnette, R. M., 116, 314 



Basheer, M., 252 

Batten, E. T., 82, 83, 106, 120, 123, 130, 

131, 138, 149, 157, 167, 171, 174, 

209, 226, 228, 229, 251, 257, 323 
Baxter, Aaron, 120, 121, 171 
Beattie, J. H., 71, 76, 82, 83, 85, 100, 116, 

157, 167, 189, 209 
Beattie, W. R., 68, 83, 157, 167, 314 
beetles, flour, 245, 246-247; saw- toothed 

grain, 245, 246; white-fringed, 235- 

240. See also insect pests 
Beritham, G., 19, 28, 58, 59, 60, 83 
Bertus, L. S., 314 
Beyer, A. H., 227, 228, 251 
Bigi, F., 314 

Bissell, T. L., 215, 246, 249, 251 
Bitancourt, A. A., 314 
Blaser, R. E., 116 
Blatchley, W. S., 251 
Bledsoe, Roger W., 89-115, 116, 118, 167- 

168, 314 
blights, 157, 198, 277-282, 304-307, 312. 

See also diseases 
blue damage, 288-290 
Bolhuis, G. G., 80, 83 
Bond, R. C, 314 
borax, see boron 
borer, lesser cornstalk, 243-244. See also 

insect pests, 
boron, 106, 108, 311. See also nutrition 
Boswell, V. R., 83 
Botrytis blights, 215, 305-306 
Bottomley, A. M., 293, 294, 295, 314, 322 
Boufifil, F., 29, 30, 38, 39, 40, 41, 56, 57, 

61, 72, 81, 83, 84 
Bower, C. A., 171 
Bradfield, R., 171 
Brady, N. C, 55, 84, 102, 116, 117, 119, 

120, 137, 143, 145, 146, 153, 168, 

170, 171 
Breda de Hahn, J. van, 314 
breeding, see genetics and breeding 
Brewer, H. E., 101, 116 
Bridgers, T. F., viii 
Bridwell, J. C., 251 
Broadbent, F. E., 121 
Brooks, A. J., 314-315 
Brown, O. A., 190, 209 



325 



326 



INDEX 



Brownrigg, George, 6, 17 
Brues, C. T., 222, 258 
Bruner, W. E., 95, 97, 117 
Bryan, O. C, 116, 168 
Buchanan, L. L., 237, 238, 252 
"bunch" (disease), 310 
Bunkley, A., 7 
Burger,' O. F., 315 
Burkart, Arturo, 84 
Burke, Emily P., 7, 16 
Burkhart, Leland, 55, 60, 84, 102, 103, 
104, 109, 111, 113, 117, 119, 168,' 315 
EuUer, C. P., 169 

cadelle, 245, 247 

Cahill, C. J., viii 

calcium, 104, 107, 108, 133-155, 311. See 
also mineral nutrition 

Calderon, S., 252 

Calhoun, P. W., 118 

Camp, J. P., 116, 153, 172, 314 

Candalle, Alphonse de, 19, 26 

Candura, G. S., 252 

carbohydrate metabolism, see metabo- 
lism 

Carver, W. A., 81, 83, 315 

Casas, Bartolome de las, 20, 26 

Cau'then, E. F., 168 

Cecil, S. R., 121, 260, 323 

Cercospora, 198, 226, 271-277, 303. See 
also leafspot 

Chaffin, J., 252 

Chaffin, W., 168 

Champion, G. C, 252 

characteristics of plant, 90-97 

charcoal rot, 267, 305. See also Sclero- 
tium 

Cheliadinora, A. I., 98, 117 

chemical composition, 106-112 

Cherian, M. C, 252 

Chester, K. Starr, 317 

Chester, K. W., 302, 315 

Chevalier, August, 16, 18, 19, 22, 25, 26, 
61, 84, 117, 252 

Chittenden, F. H., 211, 213, 217, 252 

Chitwood, B. G., 307, 315 

chlorosis, physiological, 98, 104, 311-312 

Chorin, M., 320 

Christie, J. R., 307, 315 

Christoff, A., 315 

Christova, E., 315 

Chu, V. M., 304, 315 

Ciferri, R., 314, 315 

Clark, Fred, 116, 119, 168, 169, 209, 314 



Clos, E. C, 22, 26, 61, 84 

"clump" (disease), 310 

Cockerham, K. L., 252 

Cole, J. R., 323 

collar rot, 269-271, 305, 306 

Collins, E. R., 55, 84, 102, 103, 104, 111, 

117, 150, 168, 171, 315 
Colton, H. E., 8, 9, 16 
Colville, Thomas L., 8 
Colwell, W. E., 55, 84, 116, 117, 119, 

122-166, 168, 170 
Comar, C. L., 116, 167 
Compton, R. H., 36, 84 
concealed damage, 284-288, 305, 306 
Cooper, W. E., 293, 315 
copper, 105, 106, 108, 149, 150, 311. See 

also mineral nutrition 
Corbett, G. H., 252 
corn earworm, 221-225 
Cory, E. N., 222, 223, 253 
Costa, A. S., 315 
, Cotterell, G. S., 252 
Cotton, R. T., 251, 252, 253 
cotyledons, morphology of, 29, 38-42 
Crandall, B. S., 315 
Creighton, J. T., 253 
Crosier, W. F., 315 
crown rot, 301 
cucumber beetles, 242. See also southern 

corn rootworm 
cultivation, 196-199. See also cultural 

practices 
cultural practices, 173-209 
culture of peanuts, see cultural practices 
Cumings, G. A., 167 
Cummings, R. W., vii, 171 
curing, diseases of, 284, 288. See also 

harvesting 
curl disease, see rosette 
Currin, R. E., 116, 209 

damping-off, 266-267 
Darlington, C. D., 72, 84 
Darwin, Charles, 52, 84 
Datta, Narayan P., 121 
Dean, G. A., 252, 253 
Deen, O. T., 252 
de Jong, A. W. K., 316 
De Jonghe, d'Ardoye E., 253 
De Long, Dwight M., ^26, 253 
Dent, John H., 16 
De Ong, E. R., 253 
dermestids, 245, 247-248 



INDEX 



327 



development of peanut industry in the 
United States, 6-lS 

Dew, J. A., 217 

Diabrotica, IW-lil, 244 

Diaporthe blight, 312 

Didrichsen, F., 51, 58, 84 

digging, see harvesting 

Diplodia, 270, 283, 287, 305-307 

diseases, 262-313; nutrition and, 114, 
128; resistance to, 80, 157 

disinfectants, see diseases and insect 
pests 

Ditman, L. P., 222, 223, 253 

Dobbins, T. N., 245, 254 

dolomite, see calcium 

Donald, Leroy, viii 

dormancy of seed, 100-101 
■ Douglas, W. A., 213, 215, 253 

Downing, J. C, 124, 168 

Drosdoff, M., 117 

dry rot, seedling, 267-269, 309 

Dubard, Marcel, 60, 84 

Dudley, H. C, 253 

Duggar, J. F., 137, 168 

Dunlap, A. A., 316, 318 

Dunn, Katharine R., 117 

Du Free, M., 246, 249, 251 

dusting, 198-199, 215-216. See also dis- 
eases and insect pests 

Du Tertre, R. P. J. B., 16, 25, 26 

Dyar, H. G., 217 

Easby, W. B., 7, 16 
Economic importance, 3-17 
Eddy, C. O., 215, 253 
Ejercito, J. M., 169 
Elasmopalpus, 243-244 
Ellisor, L. O., 215, 253 
embryo, morphology of, 54-55 
Empoasca, 225-230 
English, L. L., 215, 253 
Ephestia, 245, 246, 248 
epicotyl, morphology of, 29, 40-43 
Evans, M. M., 316 

Fabricius, J. C, 253 
fall armyworm, 210, 216-221 
Farrior, J. W., 154, 170 
Fenne, S. B., 316 
Fenton, F. A., 254 
Fernald, H. T., 254 
Ferris, E. B., 131, 169 
fertilization, 70, 109, 122-166, 174, 194- 
195. See also mineral nutrition 



Filcalho, de, 21, 26 

Fink, D. E., 240, 254 

Fisher, W. H., 16 

Fletcher, T. B., 247, 254 

Flint, W. P., 256 

flowers, morphology of, 49-51, 55-59, 62; 

physiology of, 91-93 
Floyd, E. H., 215, 253 
foliage, 90-91, 111-113. See also diseases 

and leaves 
food value, 14, 108-109 
Frankenfeld, J. C, 252, 253 
Frankliniella, 230-235 
Fraps, G. S., 109, 110, 112, 117 
Fratzke, W. E., 167 
Freid, M., 169 
Fronk, W. D., 245, 254 
fruit, morphology of, 55-59; physiology 

of, 91-94; shedding of, 113. See also 

diseases 
Fulton, B. B., 254 
Fulton, H. R., 316 
Funchess, M. J., 137, 168, 178, 209 
fungi, see diseases 

fungicides, see diseases and insect pests 
Fusarium, 81, 264, 267, 270, 271, 287, 

303-304 
Futral, J. G., 116, 149, 288, 316 

Galang, F. G., 84 

Gall, O. E., 116,314 

Gallup, Willis D., 110, 117 

Garren, Kenneth H., 262-313, 316 

Gasso, J. G. C, 16 

genetics and breeding, 70-83. See also 

morphology 
germination of seed, 100-101 
Gilbert, S. G., 117 
Gill, J. B., 261 
Giri, K. v., 120 
Girth, H. B., 254 - 
Glaser, R. W., 239, 254 
Goddard, Vera R., 117 
Golding, F. D., 254 
Goodman, K. V., 124, 168, 169 
Gore, U. R., 154, 157, 169 
Graham, L. T., 253 
Gray, Asa, 58, 84 
Grayson, J. M., 229, 243, 254, 257 
Green, G. D., 261 
Gregory, C. V., 26 
Gregory, Walton C, 28-83, 84, 209 
Greulach, V. A., 316 
Grizzard, A. L., 121 



328 



INDEX 



growth-promoting substances, use of, 

99-100 
grubs, white, 243. See also insect pests 
Guerrero, Joaquin, 75, 84 
Guthrie, John D., 108, 118, 120, 121 
Guyton, F. E., 212, 215, 254 
Gwaltney, P. D., 7 
gynophore, see peg 
gypsum, see calcium 

Hammer, C. L., 118 

Handy, R. B., 316 

Hansford, C. G., 295, 316 

Hanzawa, 304 

Harper, J. N., 131, 169 

Harris, Henry C, 89-115, 116, 118, 149, 

167, 168, 169, 314, 316 
Harris, T. W., 226, 254 
Harris, W. V., 254 
Harrison, A. L., 318 
Hartley, Carl, 316, 320 
Hartzell, A., 254 
harvesting, 113, 127, 160-163, 165, 187, 

199-208 
Harvey, H. W., 303, 304, 318 
Harvey, P. H., 45, 75, 84, 87, 94, 119 
Harvey, R. B., 119 
hay, peanut, see foliage; harvesting 
Hayes, R. T., 61, 77, 85, 295, 316 
Hayslip, N. C., 260 
Hazen, Myron S., viii 
Heliothis armigera, 221-225 
Henderson, C. F., 254 
Hendrix, W. E., 169 
Herbert, T. T., 321 
Heteroderes, 241, 242-243 
Higgins, B. B., 3-27, 79, 80, 85, 118, 275, 

288, 305, 316, 317 
Hill, A. G., 169 

Hinds, W. E., 215, 217, 254-255 
Hinton, H. E., 255 
Hoaglund, D. R., 118 
Hoehne, F. C, 43, 46, 60, 85 
Hoflfer, G. N., viii 
Hoflmaster, D. E., 317 
Hoffpauir, C. L., 108, 118 
hogs, grazing by, 7, 122-123, 160-163, 

165, 208 
Holdaway, F. G., 255 
Holland, Frank L., viii 
Holley, K. T., 118 
Hooker, W. A., 234, 255 
Hopkins, J. C. F., 317 
hormones, use of, 99-100 



Hosny, M., 255 

Howard, L. O., 248, 255 

Hoyt, L. F., 255 

Hull, Fred H., 61, 62, 74, 77, 78, 79, 81, 

83, 85, 87, 100, 118, 121, 315 
Hulls, see shells 
Humphrey, N., 317 
Hunn, C. J., 209 
Hunt, N. Rex., 317 
Hunter, J. H., 116, 323 
Husted, L., 71, 85 
Hutcheson, T. B., 167 
hypocotyl, morphology of, 36-38, 39 

industry, peanut, development in United 

States, 6-15 
Indian meal moth, 245-246 
Indians, use of peanuts by, 5, 6, 9, 19-22, 

25 
inflorescence, morphology of, 48-49, 62 
inheritance studies in breeding, 77-79 
inoculation of seed, 99, 194-196. See also 

diseases 
insect pests, 157, 198, 210-250, 312 
insecticides, see insect pests 
Ireland, C. F., 150, 171 
iron, 104-105, 108,311. See also mitrition 
Isely, Dwight, 226, 250, 255 
Ivanoff, S. S., 317 

Jackson, A. M., 116 

Jacobs, W. P., 52, 85, 98, 100, 118 

Jarvis, E., 247, 255 

Jefferson, Thomas, 6, 16 

Jenkins, A. E., 314 

Jenkins, W. A., 274, 317 

Jenny, H., 101, 118 

Jensen, J. S., 293, 317 

Jochems, S. C. J., 317 

Jodidi, Samuel L., 109, 119 

John, C. M., 61, 85, 86 

Johnson, C. M., 167 

Jones, B. W., 135, 169 

Josselyn, 16 

Kehring, H., 255 

KenKnight, G., 293, 299, 300, 317-318 

Kerle, W. D., 131, 169 

Kerr, J. A., 169 

Khanna, Kidar Lai, 119 

Killinger, G. B., HI, 119, 124, 169, 186, 

209 
King, George H., 209 
Krauss, F. G., 131, 169 



INDEX 



329 



Krieger, H. W., 26 
Kurtz, F., 48, 59, 85 
Kushman, L. J., 71, 85 
Kyzer, E. D., 209 

Labat, R. P., 25, 26 

Lacroix, D. S., 255 

Lane, M. C, 255 

Langley, B. C, 169 

Laphygma frugiperda, 216-221 

Larsh, H. M., 318 

Larter, L. N. H., 318 

leafhopper, potato, 106, 198, 225-230, 

231, 240, 312 
leafspot, 80, 114, 198, 226, 229-230, 262, 

271-277, 303, 310 
Leagy, J. F., 323 
Lean, O. B., 256 
Leary, Jean de, 21, 26 
leaves, morphology of, 46-47 
Leefmans, S., 256 
Legleu, R., 295, 320 
Leukel, W. A., 172 
Lever, R. J. A. W., 256 
light relations, 98 
lime, see calcium 
limestone, see calcium 
Line, C. W., 318 
Lipscomb, R. W., 318 
Littig, K. S., 257 

Liu, 100 ■* 

Livingstone, E. M., 253, 256 
Loehwing, W. F., 119 
Long, David D., viii 
Lou, 100 

Luginbill, Philip, 217, 256 
Lush, R. H., viii 
Luttrell, E. S., 318 
Lyle, Clay, 256 
Lyne, W. H., 256 

MacClenny, W. E., 16 

Macfarlane, Wallace, viii 

machinery, 8, 196-197, 199-203, 207 

Mackie, D. B., 256 

Macrophomina, 305 

magnesium, 104, 107, 108, 3i\. See also 
mineral nutrition 

maintenance of soil fertility, 155-163. 
See also fertilization 

manganese, 106, 108, 311. See also min- 
eral nutrition 

Mann, H. B., viii, 141, 169 

Marchionatto, J. B., 318 



Marggraf, Georg, 28, 85 

Marin, L., 170 

Marmor arachidis, 295 

Marsh, H. O., 256 

Martenet, R. D., viii 

Mason, C, 256 

Massibot, J. A., 132, 170 

maturation diseases, 282-284 

Maublanch, A., 318 

Maximov, Nicolai A., 119 

McClean, A. P. D., 318 

McClelland, C. K., 129, 137, 151, 169, 

179, 209 
McClintock, J. A., 318 
McCoy, E. E., 254 
McDonald, J., 318 
McGregor, E. A., 258 
McLaughlin, J. H., 317 
McNess, George T., 209 
McVickar, M. H., viii 
Meagher, W. R., 121 
Mehlich, A., 119, 146, 147, 148, 170 
Mendes, A. J. T., 71, 72, 86 
Merkl, Marvin £., 222, 256 
metabolism, carbohydrate and nitrogen, 

99 
Metcalf, C. L., 256 
Metcalf, Z. P., 106, 119, 226, 256, 312, 

318 
Meyer, Bernard S., 119 
Middleton, G. K., 94, 108, 119, 153, 154, 

170 
Miller, D., 256 
Miller, Edwin C, 89, 119 
Miller, F. E., 209 
Miller, J. H., 303, 304, 307, 318 
Miller, Lawrence L, 106, 119, 120, 185, 

209, 229, 256-257, 258, 272, 275, 276, 

318-319, 321 
Miller, P. R., 319 
mineral composition, 106-112 
mineral nutrition, 47, 89-115, 122-166, 

310-311 
Mohammad, AH, 90, 96, 119 
Mohr, H. C, 316 
molybdenum, 106, 108. See also mineral 

nutrition 
Monardes, N., 20, 26, 28, 86 
Moore, Rufus H., 98, 99, 109, 111, 112, 

119 
Moore, W. D., 319 
morphology, 28-88 

Morris, H. D., Ill, 117, 150, 168, 170 
Morwood, R. B., 319 



330 



INDEX 



Moser, F., 170 
Moses, D., 131, 170 
Murneek, A. E., 119 
Murray, G. H., 170 
Murray, Mildred D., 120 
Mycosphaerella, see leafspot 

names, vernacular, for peanuts, 6, 7, 

19-20 
National Fertilizer Association, vii, viii 
Naude, T. J., 257 
Neal, P. A., 253 
Neisler, Hugh M., 58, 86 
Nelson, R. H., 257 

Nelson, W. L., 122, 137, 149, 170, 171 
nematodes on peanuts, 307-309 
Newman, L. J., 257 
Nicholson, G., 172 
nitrogen, 103, 107, 108, 128-131, 154, 

163-154, 311. See also metabolism; 

nutrition 
nonpathogenic diseases, 310-312 
Nowell, W., 319 
Nusbaum, C. J., 319 
nutrition, mineral, 47, 89-115, 122-166, 

310-311 
nutritive value, 14, 108-109 

O'Brien, R. E., 132, 170 

O'Conner, Robert T., 120 

Okuni, T., 247, 257 

origin and early history, 18-27 

Oryzaephilus , 246 

Osterberger, B. A., 215 

Overstreet, R., 101, 118 

Oviedo y Valdes, Gonzalo Fernandez de, 

20, 26, 28, 86 
oxygen requirements, 97 
oyster shells, 138. See also calcium 

Paden, W. R., 170 

Padget, L. J., 254, 257 

Page, N. R., Ill, 113, 117, 119 

Painter, R. H., 224, 260 

Palm, B. T., 319 

Panse, E., 319 

Pantomorus leucoloma, 235-240 

Parham, S. A., 124, 170, 186, 209 

Parker, F. W., viii 

Pate, W. F., 131, 170 

Patel, J. S., 74, 77, 78, 80, 86, 119 

Paulette, J. C, 16 

Paulino, P. L., 84, 86 

peanut butter, 5, 8, 9, 14-15 



peanut oil, 3, 5, 6, 8, 9, 12, 71, 108-110 

Peanut Research Committee, viii 

Peech, M., 169, 171 

pegs, morphology of, 51-53, 58; phy- 
siology of, 91-93; mineral composi- 
tion of. 111. See also diseases 

Penicillium, 264, 270, 283, 287, 312 

pests, see insect pests 

Peterson, M. J., 124, 168 

Pettit, A. S., 33, 48, 53, 86, 96, 119 

Philips, M. W., 16 

Phillips, W. J., 222, 257 

phosphorus, 103, 107, 108, 131-132, 163, 
311. See also mineral nutrition 

photosynthesis, 99 

Phyllosticta, 303 

Phymatotrichum, 302 

physiological diseases, 310-312 

physiology, 89-115 

Pickett, T. A., 116, 118, 120 

picking, see harvesting 

Pierre, W. H., 170, 171 

Pigafetta, Antonio, 23, 26 

Piland, J. R., 117, 150, 171 

Pinkard, J. A., 319 

Piroznikova, M. F., 81, 86 

Plant Food Research Committee of the 
National Fertilizer Association, vii, 
viii 

planting, 173-187 

Pliny, 18, 19 

Plodia inter punctella, 245-246 

pods, morphology of, 53-54, 58. See also 
diseases 

Poiteau, M., 28, 58, 86 

Pole-Evans, I. B., 319 

Pollock, N. A. R., 171 

Pons, Walter A., Jr., 101, 120 

Poole, R. F., 316, 319-320 

Poos, F. W., 226, 227, 228, 229, 235, 251, 
254, 257 

Popenoe, C. H., 245, 246, 248, 258 

Porteres, R., 295, 320 

post-emergence damping off, 266-267 

potash, see potassium 

potassium, 103-104, 107, 108, 133-135, 

163-164, 311. See also mineral nutrition 

potato leafhopper, 106, 225-230, 231, 
240, 312 

pouts, 226, 231, 312 

pre-emergence diseases, 263-266 

Prevot, Pierre, 45, 46, 70, 86, 128, 171 

Prince, Alton E., 120, 320 

production figures, 3-7, 9-15 



INDEX 



331 



Purswell, Henry D., 211, 21S, 258 
Pussard, R., 258 
Pythium, 264 

Quaintance, A. L., 222, 258 
quicklime, see calcium 
Quinn, H. G., 171 

Ramakrishna, A. T. U., 258 

Ramsey, David, 6, 16 

Ray, W. Winfred, 317 

Rayss, T., 320 

Reddi, K. K., 120 

Reed, Edward L., 33, 47, 54, 86, 96, 120 

Reed, J. Fielding, 116, 119, 120, 122, 137, 
146, 148, 168, 170, 171, 190, 209 

Reed, W. D., 258 

Reeves, W. A., 118 

Reichert, I., 320 

Reisenauer, H. M., 150, 171 

reproductive morphology, 28, 48-59 

Reyes, G. M., 80, 86, 320 

Reynolds, E. G., 169 

Rhind, D., 320 

Rhizoctonia, 243, 267-268, 270, 271, 283, 
287, 309 

Rhizopus, 264, 270, 283, 312 

Rhoads, Arthur S., 320 

Richard, Achille, 28, 86 

Richter, Curt Georg, 29, 33, 36, 46, 47, 
49, 53, 54, 55, 56, 62, 86 

Rigney, J. A., 87 

Robinson, H. F., 76, 87 

Robinson, J. M., 217, 242, 258 

Rodrigo, P. A., 75, 87 

Roepke, W., 247, 258 

Rogers, H. T., 120, 137, 138, 145, 146, 
171 

Rohwer, G. G., 236 

Romasanta, R., 80, 86 

root, morphology of, 33-37, 43-45; phy- 
siology of, 94-97; mineral composi- 
tion of. 111 

root hairs, see roots 

root knot, 307-309 

root rot, 302, 303-304 

rootworm, southern corn, 240-242, 244 

rosette, 262, 293-297 

rotation and management practices, 
155-163, 165 

rots, see diseases 

Raubaud, E., 247, 258 

Russell, M. W., 53, 87 

rust, peanut, 299-301 



Sahagun, Bernardino de, 21, 26 

Sandu-Ville, C., 320 

Savelescu, T., 320 

Sayers, R. R., 253 

Scab, Sphaceloma, 301 

Schmehl„W. R., 171 

Schmidel, Ulrich, 28, 87 

Schultz, E. F., 45, 75, 84, 119, 153, 170, 

172 
Schwartz, M. B., 320 
Schwitzgebel, R. B., 253 
Sclerotinia blights, 304-305 
SclerotiumhWght or rot, 80, 128, 157, 198, 

264, 267-269, 270, 277-282, 283-284, 

287, 289-290, 305 
Seal, J. L., 321 
seed and seedling, morphology of, 29-33, 

42, 54-55, 58; mineral composition 

of, 108-110; soil rot of, 263-266. See 

also diseases 
seed per acre, 186-187 
seed preparation and treatment, 187- 

194, 264-266 
seedling, see seed and seedling 
Sell, H. M., 117 
Sellars, O. H., 168 
Sellschop, J. P. F., 131, 170, 171 
Seshadri, C. R., 61, 85, 86, 119 
Sessions, L. H., 17 
Shaw, Luther, 209, 320-321 
Shchegolev, V. N., 258 
Shear, G. M., 106, 120, 149, 171, 258, 321 
shelled vs. unshelled seed, 187-190, 264- 

265 
shelling, methods of, 189-190, 265. 5v 

also seed preparation and treatment 
shells, mineral composition of, 110-111 
Sheppard, R. A., 258 
Sherbakoff, C. D., 321 
Shibuya, T., 52, 87, 91, 93, 97, 99, 120 
Shive, J. W., 120 
Shull, A. F., 258 
Simmons, P., 258 
Skinner, J. J., 171 

Slime disease, see Bacterium solanacearum 
Sloane, Hans, 24-25, 26 
Small, W., 321 
Smalley, H. R., viii 
Smith, Ben W., 28-83, 87 
Smith, C. E., 259 
Smith, T. E., 321 
Smyth, E. G., 259 
soil, preparation of, 173-174; properties 

of, 122-125, 145-148 



332 



INDEX 



soil fertility, 109, 122-166. See also 

fertilization 
soil insects, 240-245. See also white- 
fringed beetle 
soil rots, 263-266, 282-284, 309, 312. See 

also Sclerotium blight 
Sommer, AnnaL., 120, 121, 150, 171, 321 
Soriano, S., 321 
South, F. W., 321 

southern corn rootworm, 240-242, 244 
southern root rot, see Sclerotium blight 
Souza, Gabriel Soares de, 21 
Soyer, D., 321 
Spacing of plants, 178-186 
Speairs, R. K., 321 
Species of peanuts, 59-70 
Sphaceloma scab, 301 
Squier, E. G., 19, 27 
stacking, 187, 200, 204-207. See also 

harvesting 
Stahl, A. L., 120 
Stanford, E. E., 321 
Stansbury, Mack F., 118, 121 
Stansel, R. H., 121, 172, 209 
Staten, H. W., 110, 117 
Steiner, G., 309, 321 
stem, morphology of, 36-37, 45-46 
Stewart, M. A., 259 
Stokes, W. E., vii, 74, 77, 78, 81, 87, 100, 

119, 121, 153, 169, 172, 209 
Stone, G. M., 321 
storage, 187, 208; insect pests, 210-261; 

diseases, 290-292 
Storey, H. H., 293, 294, 295, 322 
Stout, P. R., 121 
Strauss, J. L., 121 
Strong, L. A., 239, 259 
Stuckey, H. P., 172 
Sturkie, D. G., 172, 173-208, 209 
Su, M. T., 322 
Suematu, N., 304, 305, 322 
sulfur, 104, 106, 107, 108, 276, 281, 299, 

311. See also mineral nutrition 
Sundararaman, S., 322 
Swain, R. B., 239, 259 
Swank, G. R., 256 
Sweetman, H. L., 259 

Tang, P. S., 100 

Taubenhaus, J. J., 322 

Taubert, P., 59, 60, 87 

Taylor, C. P., 322 

Taylor, J. R., viii 

techniques of breeding peanuts, 73-76 



temperature relations, 98 

Tenebroides, 247 

Theophrastus, 18 

Theune, Erich, 52, 71 

Thomas, K. M., 322 

Thompson, Helen H., 121, 260, 323 

Thompson, J. M., 53, 87 

Thornton, G. D., 121 

thrips, tobacco, 74, 106, 230-235, 312 

Timson, S. D., 172 

Tisdale, H. B., 178, 209 

Tisdale, W. B., 116, 118, 169, 322 

Tissot, A. N., 118, 169 

tobacco thrips, see thrips 

Tribolium, 246-247 

Umen, D. P., 74, 81', 83, 87 

United States, development of peanut 

industry in, 6-15 
Utt, C. A. A., 9, 17 

Valdivia, M. A., 172 

Van der Goot, P., 322 

Van der Stok, J. E., 70-71, 77, 80, 87 

VanderVolk, P. G., 102, 121 

Vanselow, A. P., 121 

variability in peanuts, 59-70 

varietal differences in response to fertili- 
zation, 151-155, 165 

varieties of peanuts, 60-70 

Vaughan, E. K., 322 

Vayssiere, P., 259 

Vega, Garcillosa de la, 20 

vegetative structure of mature peanut 
plant, 43-47 

velvetbean caterpillar, 198, 210-216 

Verrill, Alpheus, 27 

viability, see germination 

Vickery, R. A., 220, 259 

Vidal, R., 132, 170 

virus diseases, 293-297 

Volk, N. J., vii 

Wadleigh, C. H., 121 

Waldron, R. A., 23, 27, 33, 34, 52, 53, 

88, 96, 121, 172 
Walkden, H. H., 253 
Walker, H. G., 251 
Wallace, C. R., 259 
Wallace, R. W., 322 
Ward, H. S., Jr., 311 
Warner, J. D., 116, 119, 169, 209, 314 
water requirements, 97 
Watkins, G. M., 323 



INDEX 



333 



Watson, J. R., 211, 212, 213, 215, 230, 

259-260 
Watson, Sir William, 6, 17 
Watts, J. G., 260 
Wear, John I., 121, 171 
Weigel, C. A., 257 
Weiss, F., 295, 323 
Weiss, H. B., 260 
Wenholz, H., 172 
West, E., 300, 323 
West, H. O., 121, 129, 171, 209 
Wheeler, C. D., 118 
white-fringed beetle, 235-240 
Williams, John Lee, 7, 17 
Williamson, J. T., 168, 173-208 
Wilson, Coyt, 114, 121, 189, 19^, 191, 

209, 216, 260, 262-313, 321, 323 
Wilson, J. P., 260, 323 
wilt, bacterial, 262, 297-299; Fusarium, 

303-304. See also blights 
Winburn, T. P., 224, 260 
Wingard, S. A., 209, 323 



Winston, J. R., 316 

Winton, Andrew L., 9, 17, 121 

Winton, Kate B., 121 

wireworm, 241, 242-243 

Wisecup, C. B., 260 

Wolf, P. A., 321, 323 

Wolk, P. C, 172 

Woodroof, J. G., 121, 260, 272, 274, 276, 

291, 323 
Woodroof, Naomi C, 323 
Woronichin, N. N., 323 

Yarbrough, John A., 28-83, 88 
York, E. T., Jr., 122-166, 172 
Young, H. C, 237, 260-261 
Yu, T. P., 324 

Zacher, P., 261 
Zimmerman, A., 324 
zinc, 106, 108, 311. See also mineral nu- 
trition