these two mixtures. The infestation records, blooms, counts, and yield records 

 each showed that the 1:4 mixtures, which averaged 2.54 lbs. of calcium arsenate 

 per acre application, were not so effective in controlling the boll weevil as either 

 of the other mixtures or calcium arsenate alone. 



Two experiments were conducted for flea hopper and boll weevil control in 

 which small plots (1/40 and 1/20 acre, respectively) were arranged in Latin 

 squares. Where the flea hopper infestation was high and damage occurred over 

 a long period (square 1), the 1:1 mixture and the 1:2 mixture of calcium arsenate 

 and sulfur gave significantly better control than sulfur alone; but where the flea 

 hoppers decreased rapidly after dusting began and caused only light damage 

 (square 2), the sulfur -arsenical mixture gave no better control than sulfur alone. 

 Apparently sulfur alone gives adequate flea hopper control when the infestation is 

 low, while the sulfur -arsenical mixtures are more effective against high infesta- 

 tions. The 1:1 mixture of calcium arsenate and sulfur (rate of 7.8 lbs, of calcium 

 arsenate per acre application) and the 1:2 mixture of calcium arsenate and sulfur 

 (rate of 5.35 lbs. of calcium arsenate per acre application) in square 1, and cal- 

 cium arsenate alone (rate of 8.22 lbs. per acre application) and the 1:2 mixture of 

 calcium arsenate and sulfur (rate of 5.43 lbs. of calcium arsenate per acre appli- 

 cation) in square 2 were equally effective in controlling boll weevils. The 1:4 mix- 

 ture of calcium arsenate and sulfur (rate of 3.2 lbs. of calcium arsenate per acre 

 application) was not so effective in controlling boll weevils as the insecticides just 

 previously mentioned. 



1938 - Gilmer, Paul M. A progress report on the control of boll weevils on sea-island 

 cotton. J. Econ. Ent. 3 1(6):684-687. 



The results of the season's work were consistent in that the dusted plots and 

 fields uniformly showed the best protection from late injury to bolls and the 

 largest increases in yields. Under conditions as they existed in 1937, the boll 

 weevil could be controlled on sea-island cotton. Sea-island cotton seems to be 

 more susceptible to arsenical injury than upland cotton. This is a serious prob- 

 lem, as a prolonged poisoning schedule appears necessary for weevil control. 

 The soils used for sea-island production are the light sandy types, seriously defi- 

 cient in potash and nitrogen, which are more subject to arsenical injury than the 

 heavier types. It was noted that where the land was well fertilized the use of 

 arsenicals did not cause sufficient shedding of leaves to reduce the number or 

 size of the bolls. 



1938 - Rainwater, C. F. Test of insecticides for control of the boll weevil, with and 

 without untreated checks. J. Econ. Ent. 31(6):682-684. 



In these experiments calcium arsenate was superior to 50-50 or 33-1/3 to 

 66-2/3 calcium arsenate plus lime for boll weevil control. There was no signifi- 

 cant difference between calcium arsenate and 50-50 calcium arsenate plus sulfur 

 for boll weevil control. The 10-90 pyrethrum plus sulfur and 33-1/3 to 66-2/3 

 barium fluosilicate plus talc showed very little, if any, value as insecticides for 

 boll weevil control. No significant difference was shown between 36% cryolite 

 and 33-1/3 to 66-2/3 calcium arsenate plus lime for boll weevil control. Owing 

 to the influence of aphids that often follow the application of arsenical insecticides, 

 yield records may not be reliable criteria for determining the actual effect of an 

 insecticide on the boll weevil. The need of an insecticide that does not increase 

 the aphid infestation or that will control the aphids along with the boll weevil is 

 clearly demonstrated in these experiments. 



1938 - Smith, G. L., A. L. Scales, and R. C. Gaines. Effectiveness of several insecti- 

 cides against three cotton insects. J. Econ. Ent. 31(6):677-682. 



Definite correlations are shown between net boll weevil mortality and the 

 following physical and chemical properties of calcium arsenate: particle size, 

 density, water-soluble AS2O5 by the New Yorkmethod, and molar ratio CaO/As205. 

 There appeared to be no significant correlations between such physical and 

 chemical properties of calcium arsenate as angle of slope, loose bulking value 

 at constant weight and constant volume, total AS2O5, water-soluble AS2O5 by the 



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