1936 - Watts, J. G. Entomology and zoology. S.C. Expt. Sta. 1935-36 Rpt. 49:39-50. 

 Dec. Clemson. 



Out of 9 combinations of insecticides tested for the control of thrips on cot- 

 ton, a dust of 10% Paris green and 90% dusting sulphur gave the greatest reduc- 

 tion in population and the lowest percentage of injured stalks; and it did not injure 

 the plants. The resistance of different varieties of cotton to this insect, as 

 measured by the percentage of injured stalks, is shown in a table and varied 

 by 13.86%. The cotton flea-hopper ( Psallus seriatus Reut.) was abundant during 

 the season, and experiments showed that the addition of Paris green to the stand- 

 ard dusting sulphur (which is applied at the rate of 15 lbs. per acre) increased 

 the killing power considerably. A dust of calcium arsenate and Paris green also 

 gave better results; it was more expensive, but it controlled the boll weevil. 



1936 - Young, M. T., and G. L. Smith. Field-plot and cage tests for boll weevil control. 



J. Econ. Ent. 29( 1): 105- 1 1 1. 



Tests with dusts against the boll weevil, at Tallulah, Louisiana, in 1933 and 

 1934. In the field tests, applications began as soon as infestation of the squares 

 reached 10%; they continued at 4-day intervals. They were made at 7:30 a.m., 

 while the cotton plants were wet with dew and the air calm. If heavy rain occurred 

 within 24 hours, the treatment was discounted or repeated. In a comparison of 

 calcium arsenate and hydrated lime mixtures and calcium arsenate, alone, both 

 gave good results. The latter was somewhat superior and gave higher yields. 

 Field and cage tests were comparable. The diphenylamine and sulphur, and 

 derris-root dust mixtures, each, had very little effect on the percent of squares 

 infested. Cage tests with both these mixtures had a higher degree of mortality of 

 weevils than field applications. A calcium arsenate-copper arsenite mixture ap- 

 peared to be superior to calcium arsenate in the field. In cage tests calcium 

 arsenate alone produced a somewhat higher boll weevil mortality. 



1937 - Bondy, F. F., and C. F. Rainwater. Boll weevil and miscellaneous cotton insect 



investigations. S.C. Expt. Sta. 1936-37 Rpt. 50:95-102. 



In experiments against the boll weevil, in South Carolina in 1936, dust treat- 

 ments applied 5 times gave control on fruiting cotton after the weevils had mi- 

 grated from old to late cotton, about mid-August. Similarly good control was 

 given by applications of 10.1 lbs. of a 1:2 mixture of calcium arsenate and lime 

 per acre, 8.9 lbs. of a 1:1 mixture, or 8.6 lbs. calcium arsenate alone. Treatment 

 was cheapest per 100 lbs. gain of seed cotton when the 1:2 mixture was used. 



In 1937 there was no appreciable control from pre-square applications of 

 mopping mixtures that contained calcium arsenate, water, and thickeners or car- 

 riers of sweets (molasses, sugarcane syrup, or maize syrup), or other materials 

 (agar agar, casein, or blood albumen). In dusting experiments, calcium arsenate, 

 alone, or mixed with lime or sulphur, was more effective than pyrethrum and 

 sulphur (1:9), cryolite, or barium fluosilicate and talc (1:2). 



1937 - Gaines, J. C. Tests of insecticides for cotton boll weevil and bollworm control 

 using the Latin square plot arrangement and analysis of variance. J. Econ. Ent. 

 30(5):785-790. 



The Latin square block arrangement with blocks of 0.05 acre was used in 

 tests of dusts for the control of Anthonomus grandis Boh. and Heliothis armigera 

 Hb. ( obsoleta , F.) on cotton in Texas in 1936. This method eliminated the varia- 

 tion due to differences of soil and uneven distribution of the insects. The analysis 

 of variance was used to interpret the data. The dusts were applied 10 times from 

 the 10th of July to the 22d of August, and all treatments gave significant control. 

 There was no significant difference in the control of A. grandis affected by 6.9 oz. 

 of calcium arsenate, 14 oz. of calcium arsenate and sulphur (1:1), 6.9 oz. of cal- 

 cium arsenate and Paris green (5%), and 6.6 oz. of calcium arsenate and lime 

 (25%) per block, but, when the dosage of calcium arsenate was reduced 25% by the 

 addition of lime, the toxicity to H. armigera was reduced. The average of the dif- 

 ferences in percentage injury on plots receiving this treatment and the three 

 others was 3.8%, and the average of the reductions in yield per block was 6.9 lbs. 



23 



