0.5% rotenone was added. Three cryolites containing 92.3%, 83.4%, and 81.3% 

 Na3AlF£,, respectively, were each used alone and with the addition of 0.5% rote- 

 none. Barium fluosilicate containing 75% BaSiF^ was used alone and with the 

 addition of 0.5% rotenone. Owing to the lack of a heavy boll weevil infestation, no 

 uniformly outstanding results on boll weevil control were obtained. Striking re- 

 sults were obtained in aphid control. 



1940 - Young, M. T., G. L. Garrison, and R„ C. Gaines. Insecticides for boll weevil 



control. J. Econ. Ent. 33(5) :787-792. 



Experiments in Louisiana in 1939 with dusts for control of the boll weevil 

 on cotton. Plots dusted early in the morning with calcium arsenate containing 

 4.6% water-soluble arsenic pentoxide by the New York method showed a signifi- 

 cant decrease in infestation over plots dusted at midday and late in the afternoon, 

 but there were no significant differences among the yields. All the plots showed 

 highly significant decreases in infestation and significant increases in yields over 

 the untreated plots. Calcium arsenate (3.5% water-soluble arsenic pentoxide) 

 caused a highly significant decrease in infestation and increase in yield, as com- 

 pared with the control, but the figures for cryolite mixtures containing 33.8% and 

 89.3% sodium fluoaluminate were not significant. 



The stronger cryolite dust caused severe scorching of the foliage, but the 

 addition to it of 1% Lethane spreader resulted in very light scorching and a sig- 

 nificant increase in yield over cryolite alone. Calcium arsenate alone and mix- 

 tures of calcium arsenate with sulphur (1:1 or 1:2) were about equal in effective- 

 ness; sulphur alone was less effective. The addition of 5% of an adhesive did not 

 improve the control given by calcium arsenate. 



Throughout the experiments the average quantity of calcium arsenate applied 

 at each dusting ranged from 5.6 to 6.4 lbs. per acre, and the average quantity of 

 cryolite, sulphur, and mixtures of calcium arsenate and sulphur applied at each 

 dusting was approximately 15 lbs. per acre. 



1941 - Ewing, K. P. Spraying versus dusting for boll weevil control. J. Econ. Ent. 



34(4):498-500. 



In tests conducted at Waco, Tex., in 1939 and 1940, a power sprayer with 3 

 nozzles per row was used in applying calcium arsenate and lead arsenate under 

 300 lbs. pressure to field cotton, in comparison with the standard dust applica- 

 tions for boll weevil control. The plots ranged in size from 1.47 to 2.66 acres. 

 There were 3 replicates each year, each replicate being in a separate field. 



In 1939, when there was a light weevil infestation, the plots sprayed with 

 lead arsenate produced slightly more cotton than those dusted with calcium ar- 

 senate. In 1940, however, under conditions of heavy boll weevil infestation, cal- 

 cium arsenate dust gave much better weevil control than calcium or lead arsenate 

 spray and resulted in larger gains in seed cotton and greater profits. 



1941 - Gaines, J. C. Tests of insecticides for boll weevil control during 1940. J. Econ. 

 Ent. 34(4):505-507. 



A special calcium arsenate containing large particles and a high percentage 

 of water-soluble arsenic pentoxide, a commercial calcium arsenate, and a cryo- 

 lite-sulfur mixture were tested against the boll weevil at College Station, Tex., 

 and Tallulah, La. Records were also kept on the aphid populations at both locations 

 and on the mirid population at Tallulah. 



The two calcium arsenates were equally effective in reducing the weevil 

 population, and there was little difference in yield. The calcium arsenates gave 

 a significant control of weevils and increases in yields over the cryolite-sulfur 

 mixtures. All insecticides gave significant control and increases in yields over 

 the checks. 



The special calcium arsenate contributed to higher increases in the aphid 

 population, but apparently not enough to affect the yield. At Tallulah the mirid 

 control was significantly better on the plats treated with the special calcium ar- 

 senate than on the plats treated with cryolite -sulfur mixture, but the population 

 was low, causing little injury. The special calcium arsenate gave better control 

 of mirids than the commercial form, but the difference was not significant. 



30 



