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CIRCULAR No. 122. Issued December 30, 1910.

United States Department of Agriculture,

BUREAU OF ENTOMOLOGY.
L. O. HOWARD, Entomologist and Chief of Bureau,

THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.¢
By W. DX HUNTER,
In Charge Southern Field Crop Insect Investigations.
AREA INFESTED.

All the regions in which the cotton boll weevil was known to occur in
1909 are shown on the accompanying map (fig. 1). It will be noticed

ERTL

CENTRAL
AMERICA

Fig. 1.—Map showing the regions in which the cotton boll weevil occurred in 1909.

that outside of the United States the insect occurs only in Mexico,
Central America, and Cuba. The infested area in Texas covers all

a The statements in this circular regarding the territory infested by the boll weevil
cover the advance made by the insect up to the close of the year 1909. Since that
time it has extended its range in the United States considerably, as will be shown in
a Map soon to be issued by the Bureau of Entomology.

68624°—Cir. 122—10

2 THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.

except the western cotton-producing counties, which in recent years
have contributed increasingly to the crop of the State. Practically
all of the State of Louisiana is within the infested territory. In
Mississippi, 23 counties are more or less infested; in Arkansas, 20;
and in Oklahoma, 15. Of the total cotton acreage in the States
concerned, the weevil is found in about 80 per cent in Texas, 30 per
cent in Arkansas, 25 per cent in Mississippi, 35 per cent in Oklahoma,
and practically 100 per cent in Louisiana. This area comprises very
nearly 30 per cent of the cotton acreage in the United States in the
year 1909, or about 37 per cent of the total number of square miles
found within the cotton belt. In other words, a portion of the
infested territory includes relatively a greater acreage devoted to
cotton than the remainder of the belt.

It is important to note that along the extreme outer edge of the
infested territory in the United States the weevils did not invade
the cotton fields until late in the season of 1909; too late, in fact, to
do any damage to the crop of that year.

The infested area includes many regions in which the boll weevil
problem takes on local aspects. There is the greatest diversity of
climatic and other conditions which react on the insect in such a
way as to establish areas of varying degrees of damage. These
individual areas will not, of course, display a constant amount of
damage each season, but in a series of years will show features that
serve to differentiate them from each other. In general, the damage
is least on the dry plains of the western portion of Texas and increases
toward the east. Where a large precipitation is combined with the
presence of an abundance of timber, as in portions of Louisiana, the
damage is greatest.

Nothing has transpired up to the present time to indicate that the
weevil will not eventually reach the northernmost and easternmost
portions of the cotton belt. Its advance to the east will be more
rapid than to the north. This is on account of the lower tempera-
ture in the north, to which it seems necessary for the weevil to adapt
itself more or less slowly. In some seasons the northward advance
will probably be checked altogether by abnormal conditions, but the
experience now acquired seems to indicate that the weevil will
eventually overcome any climatic barriers that may be encountered.
Although the advance to the east and north seems to be certain,
there is a large region in the west into which the weevil can make its
way only with very great ditliculty, if at all. In the high, open plains
of western Texas, where cotton production has developed enormously
in the last ten years, the conditions of the winters and summers
combined will probably serve as an effective barrier against the
weevil. In that region there is little timber in which the insects
may obtain shelter from the severe winters. Moreover, the normal

THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. 3

dryness of the summer compared to that in more easterly regions,
causing small plants and little shade, will act as an equally strong
check upon the insect. On account of’these conditions it can not
be considered that the boll weevil is an important menace to the
cultivation of cotton in the territory west of about the one-hundredth

meridian.
FEATURES OF THE SEASON OF 1909.

The season of 1909 was very peculiar as regards damage by the
boll weevil. The preceding season (1908) was also abnormal, but in
quite a different way. The two abnormal seasons coming in succession
have naturally given rise to various erroneous ideas about the future.

The situation in 1908 was affected first by climatic conditions of
the fall of 1907 and the following winter. These allowed an unusu-
ally small number of weevils to pass through the winter. Experi-
ments performed with many thousands of weevils in large field cages
showed a survival of about 3 per cent as against 12 per cent after the
winter preceding the season of 1907. That is, about four times as
many weevils survived to damage the crop in 1907 as in 1908. The
records based upon experimental cages were corroborated by the
inspection of about 300 fields in June, 1908. From this work it was

found that in the representative fields examined there was an average ~

of only 3 weevils per acre in northern and eastern Texas in 1908 as
against 226 per acre in 1907. In August, 1908, an examination of the
degree of infestation of squares in many localities showed 5 per cent
damage as against 54 per cent in 1907.

Following the remarkably disastrous conditions for the weevil
in 1908 in Texas came another series of checks in 1909 in Texas
in June, August, and September. This was the more important
because the pest had not had sufficient time to recover from the loss
suffered in 1908. It has been pointed out elsewhere that the most
important check to the weevil in Texas is dry weather. It has
been found that the damage done is practically in proportion to the
amount of precipitation during the growing season. As the rainfall
increases the damage becomes greater. The season of 1909 in Texas
will always be notable on account of the extremely dry and hot
weather. At Fort Worth there was a monthly deficiency in rain-
fall from February to June, inclusive, of over 1 inch. The accumu-
lated deficiency for the first seven months in the year was 10.42
inches. It must be recalled that this represents practically a third
of the normal total annual rainfall at Fort Worth. Other points in
the portion of Texas where the bulk of the crop is produced show
similar records. At Dallas, for instance, the accumulated deficiency
of the year 1909 up to August 1 was 14.28 inches, for Waco 10.98
inches, for Palestine 13.03 inches, and for Taylor 11.28 inches. In
addition to the actual shortage in rainfall very high temperatures
occurred. The drought without the high temperatures, or vice versa,
would not have affected the weevil especially. The two influences

I)

+ THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.

combined, however, served to give it such a check as it has never
experienced in this country. At many points in Texas and Louisi-
ana all records for summer temperature were exceeded. For several
days the thermometer registered over 110° F. and in some cases 114°
F. was reached. On the surface of the ground the temperature was
naturally even higher.

No one who traveled in Texas during the season of 1909 could
have failed to notice the effect of the abnormal climatic conditions
on crops of all kinds. The cotton generally grew to from one-fourth
to one-half of the normal size. The conditions were so adverse that
even variety characteristics were more or less obliterated. The
same conditions acted on the boll weevil. In fact, through large
productive areas in central and northern Texas the insect was so
reduced in numbers that it did not injure the crop to any extent
whatever.

It is interesting to note that the experience of the season of 1909
shows conclusively that while a certain degree of dry weather is
greatly to be desired for the controlling effect it has upon the boll
weevil, dryness beyond a certain degree not only affects the boll
weevil adversely, but also the cotton plant. In fact, it became evi-
dent that the cotton plant was so stunted by the dryness that it was
unable to derive any advantage whatever from the comparative
scarcity of the weevils.

DISPERSION OF 1909.

As regards dispersion, the season of 1909 was almost as unusual
as in other respects. In one region by far the largest advance ever
recorded was made by the weevil. This covered 120 miles of ter-
ritory in southern Mississippi. At the same time in Oklahoma the
greatest advance was only 30 miles, while throughout the greater
portion of that State the line was extended only about 10 miles.
A notable feature of the year’s dispersion was the failure of the
insect to extend its range considerably into the Yazoo Delta in Mis-
sissippi. During the preceding year an exceedingly light infestation
reached the extreme southern portion of the delta. This was the
vanguard of a flight that was rather extended. During the season
of 1909 the insect extended its range in that quarter only about 15
miles. Why there should be an advance of 120 miles in southern
Mississippi and only 15 in the northern portion of the State at first
seems obscure, but studies that have been made indicate the expla-
nation very clearly. One of the primary reasons for the dispersion
movement of the weevil seems to be its inclination to obtain fresh
food, and cotton squares in which to breed. Where the cotton fields
are small and separated by considerable distances, this instinct
causes the weevils to fly over a large extent of territory. On the
other hand, where cotton fields are numerous it is unnecessary for a
considerable advance to be made. In other words, a region of light

- THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. 5

cotton production causes the dispersion movement to be spread over
more territory, while a region of heavy cotton production absorbs
the weevils that are compelled to fly away from the locality in which
they were produced. This undoubtedly explains in part the failure
of the weevils to make a heavy advance into the Yazoo Delta dur-
ing the season of 1909. Moreover, there is at least one further rea-
son for the situation described. The number of weevils that enter
into the dispersion movement must naturally be dependent upon the
numbers that are bred in the cotton fields of the region from which
the dispersion takes place. A heavy infestation in a certain region,
therefore, means a large number of weevils to fly into previously
uninfested territory. In a contrary way a light infestation means a
comparatively small volume of weevils to fly beyond the original
territory. In northeastern Louisiana, the locality from which the
Yazoo Delta must naturally become infested, various conditions
caused an unusually small number of weevils to be found in the
fall of 1909. In fact, the number was not sufficient to cause a
heavy dispersion movement. It is impossible to state which of these
factors is more important, but in all probability the small number
of weevils in northeastern Louisiana and the extensive cotton fields
of the delta which absorbed the light movement were about equally
important in preventing a further advance in the Yazoo Delta than

was made in 1909.
HISTORY IN TEXAS.

Naturally the status of the boll weevil is shown by its history in the
region in the United States where it has existed for the longest time.
It is therefore important to examine the history of the insect in Texas.
On account of great climatic variations, for the purpose of determin-
ing the manner in which the boll weevil has affected cotton produc-
tion in Texas it is necessary to divide the State into three areas.
These are eastern, central, and western Texas. The divisions are
made in accordance with variations in normal annual precipitation
and other factors. Eastern Texas as used in this circular is bounded
on the west by a line running practically north and south from the
western line of Lamar County to the western line of Brazoria County.
In this region the rainfall is 45 inches per year or more. It comprises’
the counties listed below.* Practically the whole area is covered
with forests. It covers 40,180 square miles. Central Texas com-
prises a broad belt from the Gulf to the Red River, beginning on the
west with the limit of the belt of 32 inches normal annual rainfall,
and extends eastward to the line just described as defining the

@ Red River, Bowie, Franklin, Titus, Morris, Cass, Wood, Camp, Upshur, Marion,
Harrison, Smith, Gregg, Cherokee, Rusk, Panola, Nacogdoches, Shelby, San Augus-
tine, Sabine, Angelina, Trinity, San Jacinto, Polk, Tyler, Jasper, Newton, Liberty,
Hardin, Orange, Jefferson, Chambers, Galveston, Lamar, Delta, Hopkins, Rains, Van
Zandt, Henderson, Freestone, Anderson, Leon, Houston, Madison, Waller, Grimes,
Walker, Montgomery, Harris, Fort Bend, and Brazoria.

6 THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. .

western boundary of the eastern Texas area. Central Texas consists
of 45 counties* and comprises 38,868 square miles. It is for the
most part prairie country, although there are wooded valleys and
occasional strips of timbered uplands. Western Texas comprises the
remainder of Texas, beginning with the line marking the end of the
area of 32 inches normal annual precipitation. It is largely a prairie
region, though wooded valleys are numerous. Another factor in
differentiating western Texas from central Texas is the increased
elevation.

A careful study has been made of the manner in which the weevil
has affected the production of cotton in the three regions mentioned.
Use has been made of the census records of production from 1899 to
1909, a period of eleven years, as shown in the accompanying table:

Eastern, central, and western Texas cotton production compared, 1899-1909, from
United States Census.

[500-pound bales. ]

Eastern. Central. Western.a
Years. Per cent Per cent Per cent
Bales. | of Texas Bales. of Texas | Bales. | of Texas
crop. crop. crop.

SGG eee She ePE RE SIS Tah S: REF 637, 872 22.44 |} 1,633,618 62.61 | 337,528 12. 94
NG OU Sees eee ese mn eRe Bo PS es eal $11, 413 23. 59 1, 892, 669 55.04 | 734,304 21. 36
TRC ee SES NE A ape a ee he ne Ye 633, 620 20: 32 1, 448, 872 57.90 | 419,674 16. 77
OQ Dea eer ems eee. Cae ye cls TR a ee 736, 660 29.48 | 1,332, 487 53. 34 | 428, 866 iG aly
OO Smee ate se ee et eo a ES en 545, 288 22. 06 1, 242, 654 50. 28 683, 139 27. 64
Average, 1899-1908. .............-- 672,970 24.88 | 1,510,060 55.85 | 520,702 19. 26
LOGE A Sees Cee GARY gies el Beye 720, 671 22. 91 1, 700, 224 54.15 724, 475 23. 07
11S Ca) Sees eS ak eB Sa eg ae en en Pee ae 329, 523 12. 96 1,414,115 5d. 63 798, 294 31. 40
HOOGRER ie Fos Siar hae rs ERE ee 0A 4. ee Be 672, 497 16.11 | 2,213, 863 53. 03 |1, 287, 846 30. 85
OU) Te rele ag ee ae LE EE 343, 328 14. 92 1, 218, 143 52. 95 738, 708 Saeed
AGO Se ee oe Ae Rees ose ee Ow I ol 52038 13. 50 1, 980, 766 50. 60 |1, 318, 681 33. 68
QOD ee yk ht ON ef Fa 474,311 18. 80 1, 362, 096 53. 99 686, 404 27. 20

Average, 1904-1909. .............-- | 509, 228 16.53 | 1,648,201 53.39 | 925,735 29.7

aTneluding counties grouped by census under ‘‘All other.”

In eastern Texas the production for five years ending with 1903
averaged 24 per cent of the total crop of Texas. During the same
series of five years western Texas averaged 19 per cent of the total
crop. For the six years ending with 1909 the eastern Texas pro-
duction dropped to 16 per cent of the total crop of Texas, while the
production in western Texas advanced to 29 per cent of the total crop
in Texas. In other words, the portion of the Texas crop produced
in one area has decreased 24 per cent and in the other it has increased
74 per cent. This increase in the west, where the dry climate reduces
boll-weevil injury, served to offset the loss in eastern Texas, and

@Central Texas counties: Cooke, Grayson, Fannin, Denton, Collin, Hunt, Tarrant,
Dallas, Rockwall, Kaufman, Johnson, Ellis, Bosque, Hill, Navarro, McLennan, Lime-
stone, Bell, Falls, Williamson, Milam, Robertson, Brazos, Travis, Lee, Burleson,
Washington, Hays, Bastrop, Caldwell, Fayette, Colorado, Austin, Guadalupe, Gon-
zales, Lavaca, Wharton, Dewitt, Goliad, Victoria. Jackson, Refugio, Calhoun, Mata-
gorda, and Aransas.

THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. 7

thus accounts to a great extent for the fact that the total crop of the
State has not fallen off.

The table is introduced to show in what manner the State of Texas
is able to produce large crops of cotton since the advent of the weevil.
There has clearly been a falling off in the proportion of the total
crop of the State which east Texas produces. While this has hap-
pened an extensive immigration into western Texas, where the weevil
is unable to withstand the climatic conditions, has resulted in a pro-
duction which more than offsets the loss suffered in the eastern part
of the State.

The great increase in production in the western portion of Texas
is shown conspicuously by reference to individual counties. In 1899
Hall County, in the extreme western portion of the State, produced
113 bales; in 1908, over 17,000 bales. Between the same years the
crop in Jones County increased from 4,000 bales to 33,000; in Taylor
County, from 6,000 to 37,000; in Coleman County, from 8,000 to
62,000; and in Runnels County, from 3,000 to 56,000. There was an
average annual gain in the period referred to in Hall County of
over 10,000 bales; in Jones County, an average annual gain of over
22,000 bales. The other counties in that portion of the State show
similar records.

While this remarkable increase has been accomplished in western
Texas, there has been a great falling off in the eastern portion of the
State. For instance, Fannin County produced 59,000 bales in 1899
and 48,000 bales in 1908. Likewise, in the same time Red River
County fell from 29,000 bales to 18,000 bales. These conditions are
better illustrated by comparing the average annual production before
1904 and since that year. This gives a period of ten years, in half of
which the boll weevil was distributed generally in eastern Texas.
For the five years ending with 1908, the crop of Fannin County
showed an average annual loss of 16,752 bales; Lamar County, an
average annual loss of 10,246 bales; Red River County, cf 11,576
bales; and Grayson County, of 10,174 bales. ¢

«The Bureau of Plant Industry attributes the reduction in cotton ae © in
east Texas to the following causes, in addition to the boll weevil:

First. The construction of railroads and sawmills in the long-leaf pine counties,
which, by their higher wage, drew their main supply of labor from the small farms of
that section.

Second. The introduction of more profitable lines of agriculture, such as wrapper
tobacco, truck gardening, small fruits, peaches and pears, for which east Texas is
well adapted.

Third. The Texas coast rice industry, which in the past decade increased over
2,000 per cent and attracted many small farmers from east Texas.

Fourth. The general effort made by the United States Department of Agriculture

to induce the farmers to raise their home supplies, which has had considerable effect.

This readjustment of agriculture in east Texas by a reduction of the acreage in
cotton and the adding of other staple and cash crops would, however, have taken
place im any event. It was simply hastened by the advent of the weevil.

8 THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.

Mr. F. W. Gist, of the Bureau of Statistics of this Department, has
made a very careful study to determine the center of cotton produc-
tion in Texas for each year from 1899 to 1908. As would be sup-
posed from the figures that have been given, it was found by Mr. Gist
that the center of production had moved considerably to the west-
ward. In fact, this center moved from 30.78 miles east of the ninety-
seventh meridian in 1899 to 19.14 miles west of this meridian in
1908. This was a westward movement of practically 50 miles. The
center of production in 1899 was on a line passing north and south
through the eastern portion of Grayson County, in Texas. In 1908
the center had moved to a line passing parallel with the other through
the western portion of Cooke County, in Texas.

The situation in central Texas is most interesting. This area in
the five-year period ending with 1903 produced 55 per cent of the
Texas crop. For the six-year period ending with 1909 it produced
53 per cent of the Texas crop. This shows that for practical pur-
poses the production in the central portion of the State has been
maintained in spite of the weevil. This has been very largely due
to the efforts that have been put forth by the Department of Agri-
culture, and indicates that in central Texas the control of the weevil
for practical purposes is an accomplished fact.

In this connection attention may be directed to the fact that there
is a tendency to attribute to the boll weevil more damage than is
rightly chargeable to the insect. Climatic conditions, changes in
acreage, and other factors, including the work of the bollworm and
leaf worm, caused great variations in production in any locality, from
year to year, before the advent of the boll weevil. Careful allow-
ance must be made for the effects of such factors in determining the
extent to which the boll weevil has affected the crop. In the state-
ments made in this paper a careful attempt has been made to avoid
overestimating the effect on the crop due to the boll weevil.

THE CHAIN CULTIVATOR.

Though not perhaps strictly connected with the status of the
weevil, the opportunity is taken to discuss briefly an important
machine for use in weevil control. As the result of many examina-
tions to determine the natural mortality of weevils in cotton fields, it
was found that when infested squares fell to the middles, where
they were exposed to the unobstructed rays of the sun, the great
majority of the weevils perished in a remarkably short time. Under
natural conditions the bulk of the squares fall in the shade of the
plants. Therefore attempts were at once made to devise a machine
that would carry the infested squares from shaded areas to the
middles, where they would be exposed to the sun. After a great
deal of study and experimentation Dr. W. E. Hinds, now professor of

Se
Se

THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. 9

entomology in the Alabama Polytechnic College, perfected a device
that has been found to accomplish this work in a very satisfactory
manner. It consists of two series of chains arranged on a wheelless
carriage in such a way that the anterior ends pass close to the base of
the plants, while the opposite extremities pass about midway between
therows. Theinner posterior ends of the chains approach within about
8 inches of each other. As this machine is pulled through the field
the great majority of the squares are dragged to the middles and
deposited in a narrow row. In addition to the work of placing the
squares where they will be acted upon by the sun, the chain cultivator
has been found to have an exceedingly important cultural effect. It
destroys small weeds, reduces clods, and fills the cracks. In fact, it
establishes a dust mulch, which is greatly to be desired in cotton
culture.

An experiment performed in 1908 showed the effects of the prac-
tical use of this machine. Half of a small field was cultivated in part
by the chain cultivator and the remainder in the usual manner. The
yield was increased by 131 pounds of seed cotton per acre where the
machine was used. This amounted to a gain per acre of $3.93, or
practically what the machine can be manufactured for. No extra
labor was involved in the use of the machine, since its use merely
replaced the use of the ordinary implements for the later workings

_ of the crop. This experiment shows in a practical way the usefulness

of the machine, which should eventually come into common use as
much for its cultural effect as for weevil control. It is the direct
result of strictly investigational work. The inventor of this machine
surrendered all his rights as to royalties to the Department of Agri-
culture, so that itsemanufacture may be taken up by any individual
or company without the payment of fees to anyone whatever.

The possible wide usefulness of the chain cultivator was appre-
ciated by one of the largest implement concerns of the United States,
which undertook the manufacture of 100 of them to be distributed
during the season of 1909. Several practical tests were made during
that season, and they showed that the hopes for the implement were
not too high. Many planters who have witnessed the operation of
the implement are arranging to use it for corn as well as for cotton.

PARASITES OF THE WEEVIL.

The insect enemies of the weevil are practically dependent upon
it for food. Therefore any conditions that affect the weevil adversely
over a large extent of territory also affect the parasites. On this
account work of the insect enemies cf the boll weevil in 1909 was
not at all conspicuous. Nevertheless important advances were made
in the studies of the practical utilization of these enemies of the
weevil. One parasite that has attacked the weevil in Texas may have

10 THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.

extended its range to the Mississippi River, and another, hitherto
apparently restricted to the eastern portion of Louisiana, has been
found in Texas. There can be no absolute certainty that these
species have actually extended their range, but at any rate they
were found over unexpectedly large areas. The fact that they do
not appear to be as restricted to certain regions as seemed at first to
be the case undoubtedly serves to increase their potential importance
as enemies of the boll weevil.

In spite of the most unfavorable conditions the parasites caused
a considerable weevil mortality. The average total control of the
boll weevil by its insect enemies throughout the season of 1909 was
16 per cent. This total is smaller than in preceding years, but this
is clearly due to the adverse conditions in the infested areas that have
been described. It is very noticeable that the work of the parasites
in hanging squares was considerable. It ranged in Texas from 46 to
54 per cent. That is, nearly half of the weevil stages found in hang-
ing squares were destroyed by natural enemies.

The work of the year added several species to the list of known
insect enemies of the boll weevil. The list now includes 49 forms,
of which 26 are parasites in the true sense—that is, dependent upon
the boll weevil for furnishing food for their young, because their
eggs are deposited upon the weevil—and 23 are predatory species,
which merely devour the boll weevil but do not deposit their eggs
upon or in it.

IMPORTANT ADVANCE IN THE CONTROL OF THE BOLL WEEVIL.

During the season of 1909 a noteworthy advance was made in the
control of the boll weevil by means of a poison. * The credit for this
achievement belongs to Mr. Wilmon Newell, of the State Crop Pest
Commission of Louisiana. In experiments with Paris green for the
destruction of the boll weevil, carried on in previous seasons, it was
found that a certain number of the insects was killed. It occurred
to Mr. Newell that the number reached by the poison could be
increased greatly if a substance much finer than Paris green could be
obtained. Arsenate of lead was the poison that was selected. Very
large quantities of arsenate of lead may be applied to growing plants
without any injury whatever. In the use of Paris green the pres-
ence of a small amount of free arsenic causes considerable damage
to cotton plants if it is applied at the rate of as little as 5 pounds per
acre. Mr. Newell succeeded in having an entirely new form of
arsenate of lead made by one of the manufacturers of imsecticides.
The substance is an exceedingly fine powder that can be forced into
the ‘‘buds’”’ and even into the covering of the squares of the cotton
plant to a far greater extent than a comparatively coarse powder
like Paris green. The preparation of this form of arsenate of lead

THE STATUS OF THE COTTON BOLL WEEVIL IN 1909. Et

consequently obviated two important difficulties that attended the
use of Paris green; that is, the danger of burning the plants by large
applications and the difficulty in forcing the substance into the parts
of the plants where it would be taken up by the insect. Thus the
foundation was laid for very greatly increasing the mortality that
had previously been obtained from the use of another poison.

In 1909 the State Crop Pest Commission of Louisiana had thirteen
experiments with powdered arsenate of lead, located at different
places, comprising over 46 acres. The poison was applied at from 1
pound to 51 pounds per acre. In different experiments from one to
ten applications were made. In all but one of these experiments an
increased crop was obtained that resulted in a profit, after deducting
the expense incurred, which varied from a few cents to $23 per acre.
In the one experiment which did not result in a net profit an increased
yield of 121 pounds of seed cotton per acre was obtained. The very
large amount of poison used in this case (51 pounds per acre) involved
such an expense that this increased yield was not sufficient to offset
it. In the experiments in which from 10 to 23 pounds of the poison
per acre were used in from five to seven applications, the net profit
ran from $3.63 to $23.54 per acre. The most profitable amount of
the poison to be used seems thus to be indicated, although the con-
clusions from the preliminary work may be changed as the result of
_ future investigations.

It is important to note that the very encouraging results obtained
by Mr. Newell were in experiments in which the application of the
poison was made either by one of his representatives or under this
representative’s directions. A large part of the efficiency of pow-
dered arsenate of lead seems to be due to the thoroughness of the
application. It is therefore to be supposed that under the practical
conditions obtaining on plantations it may not be possible to obtain
as successful results as those in some of the experiments described.

It does not detract from the high value of Mr. Newell’s discovery
to state that all the experiments that have been performed indicate
most clearly that powdered arsenate of lead is not an absolute specific
for the weevil in the sense that it can be relied upon to the omission
or neglect of other means of control. The early fall destruction of
the cotton plants is undoubtedly a condition necessary to the suc-
cessful use of the poison. Likewise, the other steps in the system of
control advocated by the Bureau of Entomology are not minimized by
the importance of the present discovery. At most the poison merely
places another means of control at the command of the planter.
Everything indicates that it will be animportant means. Thesystem
of control in use has been to a certain extent a combination of expe-
dients for avoiding damage rather than of ways of actually killing the
weevils. In fact, the early fall destruction of the weevils by burning

12 THE STATUS OF THE COTTON BOLL WEEVIL IN 1909.

the plants has been the only important and generally applicable
direct means at the command of the planter. Powdered arsenate of
lead is especially important as a direct means of killing weevils that
may be applied at a season in which hitherto no important means of
a direct nature have been available. Extensive work that is now
being planned it is hoped will lead to definite recommendations as to
the procedure to be followed in the use of the poison for the greatest
possible profit under various conditions.

The most important difficulty that is likely to be encountered in
the use of powdered arsenate of lead against the boll weevil is the
possible deleterious effect of the poison in the soil. Recent investi-
gations conducted in orchards in Colorado where spraying of arsen-
icals has been practiced for many years seem to indicate that a con-
siderable amount of damage has resulted from the arsenic that has
become lodged in the soil near the bases of the trees. In fact, Prof.
W. P. Headden believes that in addition to the caustic effect of the
arsenic on the roots of the trees there is a probability that damage is
done the plants by absorption. At any rate, cases have been observed
where the general health of the trees seems to have been affected in
such a manner as would only seem likely to result from absorption.
Although this matter is by no means fully understood at this time,
it will be necessary to investigate carefully the possibility of injuri-
ous effects on cotton lands from repeated annual applications of
such large quantities of powdered arsenate of lead as were found to
be profitable in the experimental work in controlling the boll weevil.
If the cumulative effect of these applications is at all considerable,
the use of the poison can not be advised. At the same time there is
a possibility that something may be done in the counteracting of the
possible deleterious effects of arsenate of lead by the application of
some material with the fertilizers.

Approved:

JAMES WILSON,
Secretary of Agriculture.

Wasuineton, D. C., April 1, 1910.

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