The most practical direct method is to protect cotton by dusting with cal- 

 cium arsenate at the time when the plant is fruiting freely. Dust should be applied 

 only when active injury is occurring, as determined by counts of infested squares. 

 Local conditions should determine the details of recommendation which may be 

 made by the entomologists in the States concerned. 



Due to the World War II emergency, and the possible scarcity of arsenicals 

 and equipment, it was recommended that special emphasis be placed on cultural 

 methods of control. Such methods include early production, early fall destruction 

 of cotton stalks where practicable, consolidation of fields, and stimulation of pro- 

 duction by fertilization. 



1942 - Young, M. T., G. L. Garrison, and R. C. Gaines. Experiments on time to begin 

 dusting with calcium arsenate and number of applications for boll weevil control. 

 J. Econ. Ent. 35(4) :484-486. 



To determine when dusting with calcium arsenate should begin and the num- 

 ber of applications necessary for the most economical control of the boll weevil 

 on cotton in Louisiana, the yields obtained with applications at 4- or 5-day inter- 

 vals, beginning when 10% of the squares were infested and continuing for as long 

 as necessary, were compared with those from smaller numbers of applications, 

 begun at different infestation levels and at the time of weevil migration from 

 field to field, during the first week in August. 



The average increases in yield of seed cotton per acre was 506 lbs., in 2 

 years of experiments, for 6 applications begun at a 10% infestation level, 196 lbs., 

 for 3 applications before migration, and 292 lbs. for 3 applications begun at 

 migration. In a series of single -year tests, 8 applications beginning with an 8% 

 infestation gave an average increase of 522 lbs., 5 applications beginning at 25% 

 infestation, an increase of 580 lbs., and 4 applications beginning with a 70% in- 

 festation a 350-lb. increase. When results of 2 experiments testing the effect of 

 6 and 5 applications starting at infestations of 30%-40% and 50%-60%, respec- 

 tively, were combined, yield increases were nonsignificant. A single application 

 beginning with migration gave a yield increase of 137 lbs., 2 applications, 239 

 lbs., and 3 applications, 256 lbs. 



1942 - Young, M. T., G. L. Garrison, and R. C. Gaines. Boll weevil control with cal- 

 cium arsenate applied at different times of day and at different time intervals. 

 J. Econ. Ent. 35(4):487-489. 



An account of 2 series of experiments carried out in Louisiana to compare 

 the yields of seed cotton obtained when undiluted calcium arsenate was applied 

 for the control of Anthonomus grandis Boh., at 4- or 5-day intervals between 

 daybreak and 7 a.m., between 1 and 3 p.m. and 6 and 7:30 p.m., and when it was 

 applied in the early morning at 4-, 6-, or 8-day intervals. During 1934-35 and 

 1938-41, applications made during the early morning gave an average increase of 

 308 lbs. per acre over the control plots, those near midday gave 311 lbs., and 

 those during the late afternoon, 264 lbs. In 1934-41, applications at 4-day inter- 

 vals gave an increase of 208 lbs. per acre over the control plots, those at 6-day 

 intervals gave 143 lbs., and those at 8-day intervals, 100 lbs. 



1942 - Young, M. T., G. L. Garrison, and R. C. Gaines. Calcium arsenate with and 

 without aphicides for control of boll weevil and cotton aphid. J. Econ. Ent. 

 35(4):490-492. 



In experiments against Anthonomus grandis B oh, and Aphis gossypii Glov. on 

 cotton in Louisiana in 1941, undiluted calcium arsenate, zinc-safened calcium 

 arsenate (3.4% zinc oxide, pH 10.5), mixtures of calcium arsenate and derris, 

 cub or timbo (0.5% rotenone) and calcium arsenate mixed with nicotine sulphate 

 solution to give nicotine contents of 0.5, 1% and 2%, or with a dust containing free 

 nicotine to give 1% nicotine were equally effective against the weevil, giving sig- 

 nificant control. 



36 



