64 ANNUAL REPORTS OF DEPARTMENT OF 
August and September large areas of cotton in Texas, Oklahoma, Louisiana, and 
Arkansas were dusted with calcium arsenate to control the < ■• «t i « »n leal worm 
;in«l the boilworm, and some control of the boll weevil was obtained at the same 
I inic. 
.\t Tallulah, La., the early boll weevil Infestation was fairly heavy In May 
and June of 1935, but the hot, dry weather during July and August gave such 
natural control of the weevils that the average Increase in the 33 plots where 
calcium arsenate was applied for boll weevil control was only 153 pounds of 
seed cotton per acre, or L1.3 percent, as compared t" 236 pounds, or 19.5 percent, 
in 1934 and U9 pounds, or 45.4 percent, in 1933. in the Large series of cage and 
Held tests conducted to determine the efficacy of various Insecticides and mixtures 
of Insecticides Done was found that gave better results than calcium arsenate. 
As in previous years, the early morning applications <>f dust gave the best results, 
with the evening applications taking second place and the midday applications 
third, but the differences were not striking and indicate the possibility of boll 
weevil control by the proper application of calcium arsenate dust at any time 
of the day. In spite of the fact that in cage toxicity tests, and also as measured 
by the reduction of infestations in held tests, mixtures of ~7> percent of calcium 
arsenate and 25 percent of paris green and of !H> percent Of calcium arsenate and 
10 percent Of paris green gave better results against the boll weevil than calcium 
arsenate alone, the yields of cotton were greater in the plots dusted solely with 
calcium arsenate. These results are in agreement with tests made in previous 
years. In an extensive series of cage and held tests a mixture of derrifl and 
sulphur containing 1 percent of rotenone, a mixture of 1 part of phenothiarine to 
'.» parts of sulphur, and a mixture of equal parts of lime and calcium arsenate 
were used, but in neither cage nor held tests did any of these compare favorably 
for boll weevil control with calcium arsenate used alone. 
On the light, sandy soils of the Atlantic coastal region in the vicinity of 
Florence, S. C, in 1935. boll weevil infestation was rather light and the most 
profitable returns in control, among seven methods tested, were obtained by 
dusting with a mixture of 1 part of calcium arsenate and L! parts of hydrated 
lime after the infestation had reached K) percent. Next best was dusting with 
a mixture of equal parts of calcium arsenate and hydrated lime, a measure 
that had ranked first during several previous seasons: third best was dusting 
with calcium arsenate alone; and fourth was mopping during the presquare 
Stage with the molasses-calcium arsenate mixture, followed by the application 
of calcium arsenate dust after 10-percent infestation had been readied. The 
fad that the mixture of lime and calcium arsenate has been effective in con- 
trolling the boll weevil under the conditions existing in the Atlantic coastal 
region is of special interest, as the use of the mixtures will to some extent 
offset the objectionable features thai have developed in that region from the 
use of calcium arsenate alone. The lime mixtures reduce the danger of soil 
poisoning and of heavy aphid Infestation and at the same time are more 
economical. The addition of the lime to the calcium arsenate helps to prevent 
the growers from applying more than ."» to 5 pound- of calcium arsenate per 
acre per application. The tendency in past years has been for the -rowers 
to apply teo much calcium arsenate, i hereby Increasing the cost of poisoning 
and ;ilso the danger of Soil injury and aphid Infestations. 
Under the conditions prevailing in Mississippi during r.'-T~> the best results 
in the field plot eont rol tests were obtained from one presquare application of 
Calcium arsenate dust followed by later applications after 10-peiveut infestation 
had been reached. This was the Only method that gave greater gains and 
larger profits than dusting with calcium arsenate after Id pci-cent of the squares 
had become infested. The advantage of presquare poisoning was shown by the 
fact that in the heids receiving this treatment the b.-ii weevil Infestation was 
delayed about l week in reaching a given intensity as compared with the 
untreated fields. 
The winter of L935 ".«'< was especially severe en the boll weevil, as indicated 
by the fuel thai DO live weevils were found ill the Spring of 1936 ill Spanish- 
iii.-- ;it Florence, 8. 0., and Tallulah, La., where manj boll weevils are usually 
found during the Bpring examinations, in .-i large series ^\' hibernation i 
:it Bufaula, Okla., no boll weevils survived, at Florence the survival was lower 
than in any previous year of which we have record, and at Tallulah it was 
much bciow normal. <>niy in Texas were conditions favorable for high sur 
rival: :it Colleee Station and Port Lavaca. Tex . the weexils were more abuiid- 
