good control of cotton insects. A stabilized endrin dust gave less promising re- 

 sults, owing to poor distribution on plants. Some repellency was noted and attrib- 

 uted to the liberation of ammonia and other gases from the ammonium carbonate 

 and urea used as stabilizers in the endrin formulation. 



Two new phosphorus compounds, OS-1836 (2-chlorovinyl diethyl phosphate) 

 and OS-2046 (2-carbomethoxyisopropenyl dimethyl phosphate), in sprays gave 

 substantial reductions in populations of several cotton insects. 



1954 - Mistric, W. J., Jr., and J. C. Gaines. Effect of weather factors on the toxicity of 

 certain insecticides. J. Econ. Ent. 47(4):646-65 1. 



Laboratory cage experiments were conducted to determine the effect of wind 

 on the toxicity of emulsion sprays of toxaphene, dieldrin, and endrin when used to 

 control the boll weevil. Similar experiments were also conducted to determine 

 the effect of wind on the toxicity of toxaphene, aldrin, dieldrin, and endrin when 

 used to control the salt-marsh caterpillar. 



The results from the experiments with these 2 insects were strikingly simi- 

 lar. Simulated wind reduced the toxicity of toxaphene more than that of the other 

 materials tested. However, in the absence of wind the toxicity of toxaphene was 

 reduced less than any of the other insecticides used. Wind, therefore, appeared 

 to be the more important climatic factor studied which reduced the toxicity of 

 toxaphene. Wind was not an important factor in reducing the toxicity of aldrin 

 because aldrin lost its toxicity very rapidly, even in the absence of wind. The 

 toxicities of dieldrin and endrin were reduced appreciably by simulated wind. 

 Both the immediate and residual toxicity of endrin were slightly superior to that 

 of dieldrin. An increase in wind movement slightly decreased the toxicity of 

 insecticides, at least within the range of wind velocities tested. The effect of 

 wind was not dependent on the dosage of insecticides applied in these tests. 



1954 - Rea, James M., A. L. Hamner, and Ross E. Hutchins. Some effects of aldrin, 



BHC-DDT, dieldrin, and toxaphene on the boll weevil. J. Econ. Ent. 47(l):48-53. 



The data obtained under laboratory conditions indicate that: 



Toxaphene and dieldrin gave appreciably better control of boll weevils than 

 aldrin or BHC-DDT when applied either as a dust or spray. 



BHC-DDT gave better control as a dust than as a spray. Dust formulations 

 of aldrin, dieldrin, and toxaphene tended to give better control than sprays. 



Toxaphene gave better and faster control than the other insecticides when 

 not subjected to simulated rainfall. 



One -half inch of simulated rainfall significantly reduced the control by all 

 insecticides when applied as a dust or spray, except in the case of dieldrin ap- 

 plied as a spray. Dieldrin and toxaphene gave almost the same control after 

 exposure to 0.5 inch of simulated rain. 



A dust formulation containing 20% toxaphene, 30% Attaclay , and 50% Pyrax 

 was reduced in activity by simulated rainfall to a lesser extent than 3 other dust 

 formulations . 



The egg-laying and feeding activities of female boll weevils were reduced by 

 exposure to lethal dosages of toxaphene, even when exposed for only 2 hours. 



1954 - Smith, G. L., C. A. Richmond, and L. W. Noble. Mixtures of DDT and other in- 

 secticides for control of pink bollworms and boll weevils in southern Texas. 

 J. Econ. Ent. 47( 1) : 177- 178. 



Five large-scale insecticide experiments were conducted in southern Texas 

 in 1952 to evaluate mixtures of DDT with other insecticides for the control of the 

 pink bollworm, Pectinophora gossypiella (Saund.), and the boll weevil. The insec- 

 ticides used with DDT were EPN, dieldrin, BHC, or toxaphene. All the mixtures 

 increased the yield of seed cotton, the higher increases resulting from control of 

 the pink bollworm. The addition of DDT to dieldrin caused considerable increase 

 in boll weevil control over that obtained with dieldrin alone. The addition of EPN 

 to DDT increased pink bollworm control and gave satisfactory control of the boll 

 weevil. 



66 



