Insect damage to corn in three Southeastern States at time of harvest and in farm storage

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INSECT DAMAGE TO CORN

IN THREE SOUTHEASTERN STATES
AT TIME OF HARVEST
AND IN FARM STORAGE

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Agricultural Research Service

U.S. DEPARTMENT OF AGRICULTURE

CONTENTS

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Species and abundance of inmsects._......-..--s2-.-enesseecn coos sees
MS OCt MGC So eters eigen eg a ean Eek ae See ome
Moisture and weight per bushel______________--__-------------____-
Influence of rice weevil injury on nutrient value of corn______________
Tee oe es er esac e oe eae wees Seen eee ses

ONOPNNRH

This work was done under USDA contract No. 12—25-010-5317,
dated September 11, 1962, with Auburn University Agricultural Ex-
periment Station, Auburn, Ala.

Although the data on which this report is based were collected in 1962
and 1963, the findings are still valid and useful as guidelines for developing
research needed to find ways to prevent losses from insect attack.

Washington, D.C. Issued August 1967

For sale by the Superintendent of Documents, U.S. Government Printing Office
Washington, D.C. 20402 — Price 10 cents

;

INSECT DAMAGE TO CORN IN

THREE

SOUTHEASTERN STATES

AT TIME OF HARVEST AND IN FARM STORAGE

By W. G. Eden !

SUMMARY

Samples of stored corn collected at harvest in
Georgia, Alabama, and Mississippi, in October
1962 contained an average of about 19 insects
per pint. By July 1963, the numbers had begun to
increase, and by October they had multiplied

eightfold to 151 insects per pint. The majority of

these were the rice weevil. Of the 16 other species

found, the most numerous was the red flour beetle.

The flat grain beetle, the cadelle, and the square-

necked grain beetle, were present but not so
numerous.

The corn was X-rayed to determine insect
damage at each sampling period. The difference in

degree of effectiveness of fumigation and protective
treatments was slight, but both gave some pro-
tection to ear corn. Fumigation did protect shelled
corn somewhat, but protectants were considerably

more effective. The average weight per bushel for
the samples decreased from 53.7 pounds to 45.8
pounds during the year.

As rice weevil infestation increased, the fat
content did not change significantly but the carbo-
hydrate content of the corn decreased, and the
protein content increased. Weight per bushel of
corn and quality (weight of nutrients) decreased
significantly as rice weevil injury increased.

The loss in nutrients was the basis for estimating
the dollar loss to the crop. At harvest, insects had
already caused losses of $1,900,000 in Georgia’s
50-million-bushel corn crop, $1,300,000 in Ala-
bama’s 35 million bushels, and $760,000 in
Mississippi’s nearly 21 million bushels. By the end
of 1 year of storage on the farm these losses had
been increased to $4,565,000 in Georgia, $3,550,000
in Alabama, and $1,850,000 in Mississippi. Thus,
during the year the loss from insect damage to
farm-stored 1962-crop corn in the three South-
eastern States had increased from about $4 million
to nearly $10 million.

BACKGROUND AND OBJECTIVES

Insect damage to corn in the Southern States is
perhaps the most serious grain-insect problem
facing our country. Studies in Louisiana have
shown that an average of 10 percent of the kernels
of corn were infested at harvesttime. This damage

Increased to 17 percent after approximately 6

months of storage, and to more than 30 percent
after 9 months.” Inasmuch as insect damage to

- corn depends on several factors, including infesta-
tion at harvest, type of storage, and treatment,

data were needed on how corn was stored and
treated in these States.

A study was planned to cover the harvest and
storage of 1 year’s corn crop in three Southeastern
States. One objective was to develop a reliable
dollar value for the losses from insect attack. Data
would be sought on the factors that influence or
govern insect attack and damage to stored corn.
From such a project, guidelines might be developed
on phases of research needed to develop practical
means for preventing such losses.

'The author is an entomologist, formerly at Auburn
University, Auburn, Ala., and now at the University of
Florida, Gainesville.

2 Fioyp, BE. H., Ouiver, A. D., and PowEuu, JoE Don.

| DAMAGE TO CORN IN LOUISIANA CAUSED BY STORED-GRAIN
| insects. Jour. Econ. Ent. 52(4): 612-616. August 1959.

The study was conducted in Alabama, Georgia,
and Mississippi, three large corn-producing States
in the Southeast.2 Only farm-stored corn was
considered.

The basic objectives of this study were (1) te
determine the species, abundance, and relative
importance of various stored-corn insects through-
out the year in three Southeastern States; (2) to
establish insofar as possible the actual monetary
value of the damage caused by insects in stored
corn; and (3) to determine the kinds and extent
of insect control measures presently used and
their effectiveness.

The entire project was carried out under con-
tract with the Auburn University Agricultural
Experiment Station. Experiment station person-
nel, county agricultural agents, and farmers in the
three States cooperated in the work by locating

-corn for the study and making initial contact.*

3 U.S. DEPARTMENT OF AGRICULTURE.
STATISTICS, 1965. 635 pp. 1965.

4Dr. C. R. Jordan, Georgia; Roy J. Ledbetter, Ala-
bama; and A. G. Bennett, Mississippi, extension entomolo-
gists in their respective States, cooperated in this study.
Dr. A. E. Drake, formerly associate biometrician, and
W. H. Hearn, systems analyst, Auburn University Agri-
cultural Experiment Station, aided in the various statisti-
eal computations.

AGRICULTURAL

1

2 MARKETING RESEARCH REPORT NO. 792, U.S. DEPARTMENT OF AGRICULTURE

CORN SAMPLES

To provide samples of corn for study, 62 co-
operating farmers were selected in Georgia, 60 in
Alabama, and 66 in Mississippi. Samples of the
1962 corn crop were collected from each in Oc-
tober 1962, and January, April, July, and October
of 1963. A summary of the types of stored corn
and treatments sampled is presented in table 1. A
sample of ear corn consisted of 100 ears. For
shelled corn, probe samples taken at different lo-
cations in the bin were composited to make a
single sample of at least 1 bushel.

Of the 188 cooperators originally selected, one
was discontinued before the first sample was
collected in October; one was discontinued in
January, seven in April, nine in July, and 19 in
October. A total of 37 of the original 188 cooper-
ators were unable to provide samples at the end
of the period. Otherwise, the collection and
processing of all samples was done as indicated.

Samples were processed in the laboratory at
Auburn. Processing consisted of husking and
shelling the ear corn, sampling the uncleaned
corn for insects, cleaning, and determining the
moisture content, weight per bushel, and insect
damage. The insects were removed from the

TaBLEe 1.—Distribution of 1962-crop corn samples
im the study in 3 Southeastern States, by type of
sample and storage treatment

Type of sample Georgia) Ala- | Missis-| Aver-
and treatment bama | sippi | age, 3
States
Per- Per- Per- Per-
cent cent cent cent
Ear corn_____________ 59.7 90. 0 92.5 80.9
Fumigation ______- 0 3.3 0 1.
Protectant________ 0) 10. 0 9.2 6.4
No treatment. ___ 59.7 76.7 83.3 73.4
Shelled corn___________ 40.3 10.0 7.5 19.1
Fumigation _______ 8.1 1.6 0 3.2
Protectant_______- 6.4 6.8 3.0 583
No treatment _-____ 25.8 1.6 4.5 10.6

uncleaned subsample by screening and were
counted and classified. Moisture content of cleaned
samples was determined with a Steinlite moisture
tester. Insect damage in cleaned samples was
determined by X-ray pictures taken with ©
Westinghouse grain inspection X-ray unit.

SPECIES AND ABUNDANCE OF INSECTS

The following insect species were found in stored
corn in the three-State area:

(1) Angoumois grain moth, Sttotroga cerealella
(Olivier)

(2) Broad-horned flour beetle, Gnathocerus cor-
nutus (Fabricius)

(3) Cadelle, Tenebroides mauritanicus (Linnaeus)

(4) Cigarette beetle, Lasioderma serricorne (Fab-
ricius)

(5) Confused flour bettle, Tribolium confusum
Jacquelin duVal

(6) Corn sap beetle, Carpophilus dimidiatus
(Fabricius)

(7) Drugstore beetle, Stegobium paniceum (Lin-
naeus)

(8) Flat grain beetle, Cryptoiestes pusillus (Schén-
herr)

(9) Hairy fungus beetle,’ Typhaea stercorea
(Linnaeus)

(10) Indian-meal moth, Plodia interpunctella
(Hiibner)

(11) Lesser grain borer, Rhyzopertha dominica
(Fabricius)

(12) Red flour beetle, Tribolium casteneum (Herbst)
3) Rice weevil, Sitophilus oryzae (Linnaeus)

(14) Saw-toothed grain beetle, Oryzaephilus surin
amensis (Linnaeus)
Slender-horned flour
mazillosus (Fabricius)
Square-necked grain beetle, Cathartus quad-
ricollis (Guérin-M éneville)
(17) Yellow mealworm, Tenebrio molitor (Linnaeus)
The average number of insects by species for all
samples in each State and in the three-State area
throughout the 1-year period are given in table 2.
There was an average of about 16 insects per pint
of shelled corn from all samples (both shelled corn
and ear corn that had been shelled) in Georgia and
Alabama and 25 insects per pint in Mississippi
when the corn was stored in the fall of 1962. These
numbers remained about constant, or actually
dropped slightly, in samples collected in January
and April. They began to increase in the July
samples and had increased about eightfold by
October.

5 Trade names are used in this publication solely to
provide specific information. Mention of a trade name
does not constitute a guarantee or warranty of the product
by the U.S. Department of Agriculture and does not signify
that the product is approved to the exclusion of other
comparable products.

6 Common name not approved by the Entomological
Society of America.

(15) beetle,° Gnathocerus

(16)

ee

INSECT DAMAGE TO CORN

IN THREE SOUTHEASTERN STATES

TaBLE 2.—Numober of each species of insect per pint sample of 1962-crop shelled
corn, 3 Southeastern States, quarterly, 1962-63

Oc- Jan- April July
Species and State tober uary 1963 1963
1962 1963
Number | Number | Number | Number
Angoumois grain moth, average____--_-_- 2. 2 1.5 0. 4 1.4
GeOreia..2.-42222 e522 cee ccs tenes 2. 5 1. 4 .2 :
AlabamMéis, <<c.82cu525ecncsepaceSccn 18 1.6 3 Ty
Mississippi_...----<--.2.-.-2-ss-e005 2.3 1.5 8 2.8
Cadelle, average_____-__-----_---------- 0 04 . 05 2.1
Geonglan 2 oi eee ee eee 0 07 . 08 1.6
AlADAMA 3 2a bs 2 ces keto cee 0 05 . 02 2. 6
Mississippt.i=-. 2-25-2420 -escnse 0 0 . 05 2. 0
Confused flour beetle, average____________ .2 2 re 5
George. 2 sic 2. ke ee eee ad . 05 . 05 .2 4
AJaDAM A 2 i) ene woe etce does oll 2 2 .6
Mississippi________-_-___--_-------- £3 2 .4 6
Corn sap beetle, average________________- 1 O07 . 03 0
Georgie 2225225 eeceoncenetecelate 3 1 . 03 )
Alabamae 2.22.25 le beeen 05 03 . 07 0
Mississippi. 22.5 S4icn Seu os es eee 0 08 0 0
Flat grain beetle, average______________-- vt 2 a ee eae ee
COPS. Soca Secon eet beeen Sees . 05 . 08 . 07 0)
Alabama_____._.-_--_--_-_-------- 05 O7 a2 0
IMNSSISSIP PI: 22222 So2 2st es tk. 3 5 2 0
Indian-meal moth, average_______________ 0 0 1.3 .6
GieONGias 233222 o cee tee ee Meese 0 0 13 7
Alabamd@isi. occ eceesekaeuce dees 0 0 1.6 .2
Mississippi___-___-________________- 0 0 1.0 1. 0
Red flour beetle, average_________-_-_-_-- 0. 04 0. 2 0.1 2.9
COPA ks ee Cal te ele Boe : O «ll .2 1.0
Alabama... -22..--4-22-iscees =e 05 . 08 . 07 5. 5
Mississippi_..-___-________________- 05 .3 2 2. 1
Rice weevil, average___._._.__-_-_-_-_-- 9. 6 8.3 8.9 20. 4
COLPIA@ nia nance eculeeeeeces 7.4 6. 9 10. 3 16.8
Alabama______________--__---_---- 7.2 7.5 6. 4 26.5
Mississippi________________________- 14.3 10. 5 10. 0 17. 9
Saw-toothed grain beetle, average________- 0 . 07 zal 9
Georgia = 22 fe cre et oe 0 08 . 08 .8
Alabama. _____________________ Le 0 . 05 . 05 4
MASSISSID PIs 2c oe ceed ee eee ee 0 08 .38 1.4
Square-necked grain beetle, average______- 6. 6 6.5 2.9 1.6
Ge@OPele 23222525225. osscnsen ane as 5.5 9. 8 2.7 1.2
AIJADOING 2 J cSa5e bet cee aecet 6. 3 4.8 3. 3 2. 0
Mississippi_________-___-_-_ ee 7.9 4,8 2. 6 1.5
Yellow mealworm, average______________- 0 0 0 0
Georgia 22. oo. ee ee eee 0 0 0 0
Alabama. 22 25 20 eos eek ache 0 0 0 0
Mississippi_____________-__-________- 0 0 0 0
Miscellaneous species, average !___-______- 06 02 0 1,2
Georgiae | 223 oo Oe 12 . 02 0 .8
Algbameay. 232 uss 2 tea et 06 . 03 0 1.5
Mississippi__________- ee 02 02 ) 1. 2
Total, all species, average. __-__ 18. 9 17. 1 14, 2 ol. 6
Georgia__________________________- 15. 9 18. 6 15,2 23. 7
Alabama. _________________________ 15. 6 14. 4 12. 2 40. 4
Mississippi_-__-__-_--- 25. 2 18. 0 15. 6 30. 5

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‘Includes combined numbers of hairy fungus beetle, cigarette beetle, drugstore beetle,
broad-horned flour beetle, slender-horned flour beetle, and lesser grain borer.

4 MARKETING RESEARCH REPORT NO.

The rice weevil was, by far, the most numerous
species of insect in the stored corn in each of the
States. In numbers it made up one-half or more of
all insects collected in October 1962 and the
following January and April. The proportion of
rice weevils increased in the July samples, and by
October 1963 the rice weevil constituted more than
70 percent of the 151.1 insects per pint of all
samples. The average sample in Georgia con-

792, U.S. DEPARTMENT OF AGRICULTURE

tained 88.6, in Alabama 168.1, and in Mississippi
196.5 insects per pint.

By the end of the l-year storage period, the

second most numerous species in each State was
the red flour beetle, which made up about 7.5
percent of the total. Of still lesser importance
were the flat grain beetle, the cadelle, and the
square-necked grain beetle. In Alabama the corn
sap beetle and in Mississippi the Angoumois grain
moth were also important.

INSECT DAMAGE

Insect damage throughout the year, as shown by
X-ray examination of the samples for the three-
State area, is given in table 3. The averages for
all samples show an initial 12.2 percent of the
kernels damaged by insects. This increased
eradually throughout the 1-year storage period to
38.1 percent. In Georgia this increase was from
11.6 to 32.7 percent, in Alabama from 10.7 to
38.2 percent, and in Mississippi from 14.2 to 43.4
percent.

Injury in the untreated ear corn increased from
an initial percentage of 11.6 to 37.5 for the three
States at the end of the year. In Georgia, the
average gradually increased from 10.7 percent of
the kernels when storage began to 26.3 percent at
the end of the period. The injury in Alabama
gradually increased from 10.1 percent to 40.3 per-
cent. In Mississippi, the injury was 14.1 percent
when storage began, and 45.8 percent at the end
of the year.

Fumigated ear corn was sampled in Alabama
only. It had 8.5 percent damage at the beginning
and increased to 23.1 percent at the end of the
storage period.

Ear corn treated with protectant in Alabama
had 13.2 percent kernel injury at the beginning of
storage, which increased to 35.3 percent. In
Mississippi, ear corn treated with protectant
started with 15.7 percent injury at the beginning
of storage, but increased to only 18.2 percent at
the end. No ear corn treated with protectant was
sampled in Georgia.

Insect damage in untreated shelled corn for two
of the States increased from an initial 13.6 percent
damage to 51.9 percent in 1 year. In Georgia, 13.5
percent of the kernels were injured when storage
began and this increased to 43.8 percent at the
end of 1 year; in Mississippi the increase was from
14.9 percent to 60 percent. In Alabama, coop-
erators were unable to hold untreated shelled corn
throughout the year, so no comparison of the

treated with untreated shelled corn could be made.

In fumigated shelled corn the average kernel ©

injury in all States increased from 13.2 percent to
40.4 percent. In Georgia, the injury in fumigated
shelled corn increased from 12.6 percent average
damage at the beginning to only 26.9 percent in
July, compared to 39 in the untreated. By the end
of the year, however, it was 41.5 percent, almost

—

as much as in the untreated corn. The increase in ©

Alabama was from 13.7 percent injury to 39.3
percent. None of the shelled corn sampled in
Mississippi had been fumigated.

In shelled corn treated with protectants in all
three States, the average increase in insect injury
was from 12.9 percent of the kernels to 26.7
percent. In Georgia, the injury was 12.6 percent
at the beginning of storage; it increased more
slowly than in the untreated or fumigated corn
and was 34.9 percent at the end of the year. In
Alabama, injury increased from 138.8 percent
initially to 30.1 percent at the end of the year.
Shelled corn treated with protectants in Mississippi
increased to only 15 percent kernel injury from an
initial 12.3 percent.

Thus, while fumigation of shelled corn resulted
in less insect injury than no treatment, the use of
protectants was considerably more effective in
all three States. In ear corn, protectants gave
excellent control of insects in Mississippi. In
Alabama, the only State in which fumigants and
protectants could be compared for ear corn, fumi-
gation resulted in better insect control than the
use of protectants or no treatment.

There was greater injury during the year to
untreated shelled corn than to untreated ear
corn, both in Georgia and Mississippi. Injury in
untreated ear corn increased in all States from
11.6 to 37. 5 percent of the kernels in 1 year, but
it increased from 13.6 to 51.9 in untreated shelled
corn.

INSECT DAMAGE TO CORN IN

THREE SOUTHEASTERN STATES 5

TaBLE 3.—Percentage of 1962-crop corn kernels damaged by insects in each type
of sample and storage treatment, 3 Southeastern States, quarterly, 1962-63

State, type of sample, and storage October | January | April July | October
treatment 1962 1963 1963 1963 1963
GEORGIA
Percent | Percent | Percent | Percent | Percent
All samples, average___--_----_------_--- 11.6 13. 5 19.9 25. 5 32.7
Ear corn:
No treatment _____ eats See ee eee 10. 7 12. 7 16. 7 20. 7 26. 3
Shelled corn, average____--__------------ 12. 9 14.3 23. 8 29. 0 40. 1
MumigatiOni. o-22525.02s5-2s2e50256 12.6 15. 6 28. 4 26. 9 41.5
Protectant________ ee etietet alee 12.6 12. 1 17.8 21.1 34.9
No treatment_____-___-___-_------- 13. 5 15. 3 25. 3 39. 0 43. 8
ALABAMA
All samples, average____---------------- 10. 7 14. 1 18. 1 25. 4 38. 2
Ear corn, average___-_------------------ 10. 6 14.3 20. 8 23. 2 32.9
Fumigation______-__--------------- 8.5 15. 1 27.6 25. 2 23. 1
Protectant_____-_------------------ 13. 2 13. 9 17. 1 17.9 35. 3
No treatment______---------------- 10. 1 14. 0 17.8 26. 4 40. 3
Shelled corn, average. --_---------------- 13. 3 14.6 17. 6 23. 6 34. 7
Pumigation. 22. 32..s2cs<sh.secece82 13. 7 14.8 16. 2 19.8 39. 3
Protectant_____-------------------- 13. 8 12:1 19. 0 27.3 30. 1
No treatment. _---------_----------- 12.5 VON ee eee let Ae as eae =
MISSISSIPPI
All samples, average____----_-_--------- 14. 2 14. 4 19. 7 29. 4 43. 4
Ear corn, average_._-_-_----------------- 14.9 15. 8 22. 5 23. 8 32. 0
Protectant. ......2--52--2ossetccese 15. 7 17.9 27.1 17.7 18. 2
No treatment._-.-_---------------- 14.1 13. 7 17.9 29.9 45.8
Shelled corn, average____-----_---------- 13. 6 17.5 29. 1 30. 7 37. 5
Protectaht.-2-- 2 se sehen dees eked 12.3 12.8 21. 6 13. 4 15. 0
No treatment. _-___-__-_----------- 14.9 22. 1 36. 5 47.9 60. 0
3 STATES
All samples, average______-___---------- 12. 2 14. 0 19. 2 26. 8 38. 1
Ear corn, average_-_-_-- Boo e eee eee 11,5 14.8 22. 4 22.9 29. 1
Pumigation. 222222552025 5e2.6eeehee 8.5 15. 1 27.6 25. 2 23. 1
Protectatt.2222 6 22.2552 2eeth ee 14. 5 15.9 22. 1 17.8 26.8
No treatment__-__--_------_------- 11.6 13. 5 17.5 25. 7 37.5
Shelled corn, average____---------------- 13. 2 15, 2 24. 2 29, 2 39. 7
Fumigation______--__-------------- 13. 2 15. 2 22.3 23. 4 40. 4
Protectant_____ ee ee ee aaa oe 12.9 12.3 19.5 20. 6 26. 7
No treatment______-__----.-------- 13. 6 18. 1 30. 9 43.5 51.9

MOISTURE AND WEIGHT PER BUSHEL

Moisture content and weight per bushel of the
corn samples varied little between one State and
another (table 4).

Moisture content for all samples in the three
States decreased from 13.2 percent when storage
began to 11.1 at the end of 1 year. Although the
moisture content of the shelled samples was
slightly lower than that of ear corn in the beginning
of the study, the two were essentially the same at

the end of a year of storage. Treatment with
protectants or fumigants appeared to have little
effect on moisture content of the corn.

The average weight per bushel of all samples
was 53.7 pounds initially, and it gradually re-
duced to 45.8 pounds at the end of the period.
The average weights per bushel of corn seemed
to vary little between ear corn and shelled or
between treated and untreated corn.

6 MARKETING RESEARCH REPORT NO. 792, U.S. DEPARTMENT OF AGRICULTURE

TABLE 4.— Moisture content and weight per bushel of 1962-crop corn, by type of sample and storage treatment, .
8 Southeastern States, quarterly, 1962-68 ;

; October 1962 | January 1963 April 1963 July 1963 October 1963
State, type of sample, and -
storage treatment
Mois- | Weight | Mois- |Weight | Mois- | Weight | Mois- | Weight} Mois- | Weight »
ture ture ture ture ture }
GEORGIA H
Percent | Pounds| Percent | Pounds | Percent | Pounds | Percent | Pounds | Percent | Pounds |
All samples, average____________-- 13.2 54. 0 13.8 52.1 11.8 51.7 11.5 50. 0 11.3 46.5.
Ear corn:
No treatment______________- 13.5 53.9 14.0 51,7 12.0 51.4 11.6 50. 4 10.9 47.2
Shelled corn, average_____________ 12.7 54.3 13:5 53.1 it. 7 52.6 11.3 50. 2 11.6 46.3
Fumigation_......_._.-.___- 12.6 54.6 13.7 52.8 12.1 53. 2 11.2 50.5 11.3 46.0
Protectatits:22 22. 22.<s2s2s8 12.8 54. 2 13.3 54. 2 11.6 52.9 11,7 51.8 11.2 48.2
No treatment._____________- 12.8 54. 0 13.6 52.3 11.3 51.8 11,4 48.2 12-2 44.7
ALABAMA |
All samples, average_____________- 13.2] 3588) 19:9) 52.9 | 128-1, Sa3|)) Tit 1 SOS) “tas 46.0)
Ear corn, average_______ .________ 13.5 53.8 13.9 52.4 12.4 51.5 11.1 50.3 11.3 45.3 |
Fumigation_________________ 14.3 54. 2 14.4 53.1 12.9 51.5 11.1 50. 0 LL e% 42.71
Protectant. _-__-_______-_-_-- 12.8 | 53.6 13.4 | 52.2 12.1 51.7 11.3 | 50.8 11,4 47.3
No treatment_______________ 1333 53.7 14.0 52.0 12:2 51.2 Tt: 0 50. 2 11.1 45.9 -
Shelled corn, average_____________ 12.8 54.5 13.4 52.6 12.9 52.1 11.6 51.4 11.1 47.5 |
Fumigation. ________________ 13.4 56. 4 14.6 54.5 12.9 52.2 12.0 52.0 11.0 49.1.
Protectant._.______________- 12.2 53.8 13.3 52.5 12.8 51.9 1.2 50.8 oe ee 45.9.
No treatment______________- 12.7 53.4 12.2 DONT: (oie c2 oe laecsees|o525osslsooncce lee se3e a eee
MISSISSIPPI
All samples, average______________ 13.1 53.4 13.9 i lees) 12.1 61.2 11,1 49.8 10.8 45.0
Ear corn, average________________ 12.7 52.4 13.7 50. 4 12.0 50. 2 11:0 5021 10.8 46.3
Protectante..<. 22.2. .-62.5 25+ 12.2 51.0 13.4 48.9 11.8 48.9 10.9 50. 4 10.8 48.2
No treatment______________- 13.2 53.7 14.5 51.8 12.2 515 i tL 49.8 10.8 44.4
Shelled corn, average____________- 12.5 53.3 14.2 51.5 12.1 50.6 10. 7 49.8 10.8 48.2
Protectant_________________- 12.0 52.6 13.9 51.8 11.9 50.7 10.6 50. 2 11.0 49.4
No treatment_____________-- 12.9 53.9 14.4 51.1 12.2 50. 5 10.8 49.4 10.5 47.0
3 STATES
All samples, average_______-_ a 13. 2 53.7 13.9 51.9 12.1 51.4 1142 50. 0 i 45.8
Ear corn, average_._____________- 13.4 53. 4 13.9 51.7 12.4 51.1 11.1 50. 2 11.2 45.4
Fumigation_______._________- 14.3 54. 2 14.4 53.1 12.9 51.5 ts & 50. 0 11.7 42.7
Protectant_________________- 12.5 52.3 13.4 50. 1 12.0 50.3 11.1 50.6 11.0 47.8
No treatment______________- 13.3 53.8 14.0 51.8 12.2 51.4 11.2 50. 1 10.9 45.8
Shelled corn, average.___________- 12.7 52.6 13.7 52.6 12.1 51.9 11.3 50.3 Li e2 46.6
Fumigation_________________ 13.0 50.5 14.2 53.7 1225 52.7 11.6 59 ea 11,2 46.0
Protectant____...._____.__--- 12.3 538.5 13.5 52.8 12.1 51.8 11.:2 50.9 1 47.8
No treatment______________- 12.8 53.8 13.4 51.4 11.8 51.2 140 48.8 11.4 45.9

| INSECT DAMAGE TO CORN IN THREE SOUTHEASTERN STATES

ri

INFLUENCE OF RICE WEEVIL INJURY ON NUTRIENT VALUE OF CORN

| The effect of infestation by rice weevils on the
nutrient value of corn was estimated from data
‘on the content of the carbohydrates, proteins, and
fats remaining in the kernels. At this stage there
“were no samples that had no insect damage to the
kernels, and since it was not possible to set up
these samples so that a given percentage of kernel
damage would result from the weevil infestations,
‘regression equations were worked out on the basis
of the data available. From these equations, the
‘probable average percentages of each type of
nutrient and the total nutrient content of the
‘corn were worked out for various gradations of
weevil damage to the corn. Regression equations
were also used to estimate the probable weight of
the corn per bushel at the given percentage of
weevil damage and the pounds per bushel that
consisted of nutrients. From the predicted weight
of nutrients per bushel, the percentage of loss in
nutrient value was calculated. These figures are
shown in table 5.

__ The predicted carbohydrate content of the corn
decreased as the weevil infestation increased. The
decrease was from more than an estimated 76
percent carbohydrate content at 10 percent kernel
infestation to less than 70.9 percent at 100 percent
infestation. The protein content increased very

slightly as rice weevil infestation increased. Al-
though the change was not large (less than 2
percent between 10 and 100 percent infestation),
the original data showed a definite and steady in-
crease. The changes in fat content shown in table 5
were predicted from a cubic regression equation,
which was the best fitting equation, but even this
equation was not significant statistically. From the
limited data available, it was not possible to de-
termine whether weevil infestation exerted any
consistent influence on fat content.

The predicted totai percent of nutrients tended
to increase as infestation rose to 40 percent.
Above 40 percent infestation, the percent of total
nutrients dropped markedly.

As weevil infestation increased, the weight per
bushel of corn decreased At 10 percent infesta-
tion, the weight per bushel was more than 54
pounds, and it was less than 43 pounds at 100
percent infestation.

The nutritive value of corn was reduced con-
siderably as rice weevil infestation increased. At
10 percent weevil infestation, the total nutrients
weighed more than 49 pounds per bushel, but
weighed less than 37 pounds at 100 percent in-
festation.

| TABLE 5.—Estimates of effect of rice weevil infestation on weight and nutrient content of corn’

Nutrient content of corn Loss in
eee total
Kernels damaged eight nutrient
by weevils (percent) | of corn 2 Carbo- Total 2 value of
hydrates | Proteins Fats corn
Pounds|/ Pounds/
bushel Percent Percent Percent Percent bushel Percent
pemts oe Ne Os 55. 8 76.8 9. 4 5. 8 87. 2 50. 7 0
1k) a ners 54. 4 76. 2 9. 6 5. 0 88. 7 49. 3 2.7
P|. een ee eee 53. 1 75. 6 9.8 4.7 89. 8 47.9 5. 4
+ | | eee eee ne eee Eas 51.8 75. O 10. 0 + 4.6 90. 5 46. 5 8. 2
| 7 ner 50. 5 74.4 10. 1 4.8 90. 7 45, 2 10. 9
| Oe ao ee et 49. 1 73. 8 10. 3 5. 1 90. 6 43.8 13. 6
| 60: ten oslse2e58 47.8 73. 2 LO: 5. 4 90. 1 42.4 16. 3
A) cee ate nL ee es 46. 5 72. 6 10. 7 5.5 89. 1 41. 0 19. 1
BOY Fo ee 45. 2 72. 1 10.8 5.3 87.8 39. 7 21.8
QOS 2o Se Saeaee 43. 8 a les 11. 0 4.7 86. 0 38. 3 24. 5
VOOSs eco sete eee 42. 5 70.9 11.2 3.5 83. 9 36. 9 27. 2

! Derived from best-fitting regression equations.
2 These figures are calculated by formulas from original data, not from other columns of this table.

8 MARKETING RESEARCH REPORT NO. 792, U.S. DEPARTMENT OF AGRICULTURE

LOSSES

Dollar losses to the 1962 corn crop from stored-
grain pests were calculated for each State at the
time the corn was stored and quarterly for the
following year. The loss in weight of nutrients per
bushel was used as the basis for calculating losses.
The corn stocks on hand by quarters (table 6)
were used in the estimates. The average percent of
damaged kernels (table 3) in each type of storage
and treatment on each date for the three States
were converted to percent losses. The percent losses
were applied to the bushels of corn in each type of
storage and treatment at the end of the quarter.
The average price received by farmers (table 7)
was applied to the calculated bushel loss to give
dollar loss (table 8). Losses of ear corn fumigated
and treated with protectants in Georgia and fu-
migated ear and shelled corn in Mississippi were
calculated from percentages of the crop estimated
by county agents to have been so treated.

TABLE 6.—Production and quarterly stocks of 1962
corn crop, 8 Southeastern States, 1962-68 }

Date | | Georgia Alabama) Missis- | Total,

sippi | 3 States

| 1,000 1,000 1,000 1,000

| bushels bushels | bushels | bushels
Oct. 1, 1962_______| 50, 760 | 35,026 | 20, 628 | 106, 414
Jan. 1, 1963_______ | 18, 214 | 23, 857 | 11, 758 53, 829
Apr... 1, 1963_...- - | 12, 690 8, 406 4,951 26, 047
July 1, 1963______- | 5,584] 4, 203 1, 444 11, 231
Oct. 1, 1963_______ | Waid 1, 051 2722 3, 238

1 Statistical Reporting Service, U.S. Depakiaent of
Agriculture.

2 This figure was not available from the Statistical Re-
porting Service. The average percent of reduction in corn
stocks in Georgia and Alabama between July and October

was applied to the July figure in Mississippi.

TABLE 7.—Average price per bushel recewed by
farmers for corn, 8 Southeastern States, quarterly,
1962-63 } |

|
|
Date Georgia | Alabama} Missis- | Average, | |
sippi_ | 3 States |

Dollars | Dollars | Dollars | Dollars

Nov. 15, 1962_____ 1. 26 1. 20 1. 18 1.21
Feb. 15, 1963__ __- 1.38 1, 31 1.35 1, 35]
May 15, 1963_____ 1. 41 1. 36 1. 35 1. 37,
Aug. 15, 1963____- 1.41 1. 36 1. 40 1. 39

' Statistical Reporting Service,

U.S. Department of
Agriculture.

There had been a loss of nearly $4 million
caused by stored-grain pests in the three States

at the time the crop went into storage, and this |

damage increased as the storage period lengthened. |

Al

By the end of the storage year the loss amounted

to nearly $10 million.

In the Georgia corn crop of more than 50 |
million bushels, damage from stored-grain in-
sects increased from nearly $2 million when the
corn went into storage to $4! million by the end
of the year.

The loss of $1.3 million to the 35-million- ||

bushel Alabama corn crop when it was put into
storage had become $3%
the year.

The corn crop was short in Mississippi in 1962;

production was only 20.6 million bushels. How-

ever, more than three-quarters of a million dollars
was lost to stored-grain pests before the crop was
stored. Nearly $2 “million had been lost by the
end of the year of storage.

million by the end of |!

§

|
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i

INSECT DAMAGE TO CORN IN

THREE SOUTHEASTERN STATES

storage on farm, by type of sample and storage treatment, 3 Southeastern States, quarterly, 1962-63

9

‘Taste 8.—Dollar value of losses caused by stored-grain insects to 1962-crop corn at harvest and during

State, type of sample, and Previous | October to | January to April to July to
storage treatment to storage | December, | March, 1963) June, 1963 | September, Total
1962 | 1963

GEORGIA 1,000 1,000 1,000 1,000 1,000 1,000

dollars dollars dollars dollars dollars dollars
/All samples, all treatments____________ 1, 916.8 885.8 953.5 562. 4 247.1 4, 565. 7
‘Ear corn, all treatments______________ 1, 646. 5 759.8 795.3 469.9 209. 2 3, 880. 6
Fumigation____________________- 145.7 97.8 136. 4 56. 0 16.4 452.4
Protectant____.....__...-._____-- 163. 2 67.3 71.6 25.9 12.4 340. 4
No treatment__________________- 1, 337.6 594.6 587.3 388. 0 180.3 3, 087.8
/Shelled corn, all treatments__________- 270.3 126. 1 158. 2 92.5 38. 0 685. 0
Fumigation. --_-____- ee 67.6 29.3 32.9 1525 8.6 153.7
Protectant_____________________-_ 34. 1 12.2 14.8 7.0 3.0 C12
No treatment___________________ 168. 6 84.5 110.5 70.0 26.5 460. 0

ALABAMA
All samples, all treatments____________ 1, 301.0 1, 105.1 599. 6 408. 2 141.0 3, 554.9
Ear corn, all treatments______________ 1, 119.2 947.7 500. 0 341.1 119.4 3, 027.4
Fumigation______________ Le 98.0 122.1 85.8 40.7 9.3 355.8
Protectant____-______-_ =e 109.8 83.9 45.0 18.8 7.1 264. 6
No treatment. _______________ Le 911.3 741.8 369. 2 281.7 102.9 2, 406.9
Shelled corn, all treatments___________ 181.8 157.4 99.5 67.2 21.6 527.5
Fumigation___-__-__________ ee 45.5 36. 7 20.7 11.3 4.8 119.0
Protectant______________w. -____ 22.9 15.3 9.3 5.1 1.7 54.3
No treatment___________________ 113.4 105. 4 69.5 50.7 15.2 354. 2
MISSISSIPPI
All samples, all treatments____________ 759.7 535.6 363.9 139. 2 56.7 1, 855. 0
Ear corn, all treatments_____________- 653.5 459.3 303. 5 116. 4 47.9 1, 580. 6
Fumigation_______.____________- 57.2 59.2 52.1 13.9 3.8 186. 1
Protectant.____________________-_ 64. 1 40.7 27.3 6.4 2.9 141.4
No treatment__________________- 532.1 359. 5 224.1 96. 1 41.3 1, 253. 1
Shelled corn, all treatments___________ 106. 2 76.2 60. 4 22.9 8.8 274. 4
Fumigation. -------= 26.6 17:7 12.6 3.9 2.0 62.7
Protectant___-_________-_- ee 13.4 7.4 5.6 1.7 6 28.8
No treatment. ____________ =e 66. 2 51.1 42.1 17.3 6.1 182.8
3 STATES

All samples, all treatments____________ 3 977.5 2,526.5 1, 916.9 1, 109.8 444.8 9, 975. 5
Ear corn, all treatments__________---- 3, 419. 2 2,166.8 1, 598.8 927.3 376. 4 8, 488. 6
Pumiga@tion. 2 .c2nscnnecencaes 301.0 279.1 274.3 110.5 29.5 994. 3
Protectant__-_---_--_ ee 337.1 191.9 143.9 51.0 22.4 746. 4
No treatment. ____-___ =e 2,781. 1 1, 695.9 1, 180.6 765.7 324.5 6, 747.9
Shelled corn, all treatments__________- 558.3 359.7 318.1 182.5 68.3 1, 486. 9
Fumigation._--.-..2--5.-2-.225- 139.7 83.7 66. 2 30.7 15.3 335. 6
Protectant.....--..-....2-.-...-- 70. 4 35.0 29.8 13.9 5.2 154. 3
No treatment__________________- 348. 2 241.0 222.1 137.9 47.8 997.1

U. S. GOVERNMENT PRINTING

OFFICE :

1967 O - 262-101

Fed thendbche tech Goao ames
Raneecae “ ste

NTE ar seni it gr ew Serta
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