1950 - Isely, Dwight. Control of the boll weevil and the cotton aphid in Arkansas. Ark. 

 Agr. Expt. Sta. B. 496. June. Fayetteville. 



Outbreaks of aphids tend to follow outbreaks of weevils when insecticidal 

 control is undertaken, especially with Ca arsenate. Controls with calcium arsen- 

 ate, toxaphene, and 3-5-40 (BHC- DDT- sulfur) are discussed. 



1950 - Ivy, E. E., and A. L. Scales. Dieldrin for cotton insect control. J. Econ. Ent. 

 43(5):591-592. 



Tests were conducted in field cages and in the laboratory. 



A dust containing 5% of dieldrin gave a higher kill of weevils, and one con- 

 taining 2.5%, a slightly lower kill than the 20% toxaphene dust. Statistically, there 

 was no significant difference in the effectiveness of these 3 formulations. How- 

 ever, a dust containing 1.25 percent of dieldrin gave a significantly lower kill. 



Sprays were applied at the rate of 3 gallons per acre. 



Dieldrin in both spray and dust formulations appears to be somewhat more 

 resistant to removal by rain than does toxaphene. 



After artificial showers, sprays or dusts at 0.25 and 0.5 pound of dieldrin per 

 acre were more effective than toxaphene at 2 pounds per acre. The addition of 

 either of 2 commercial stickers, applied at the rate of 0.5 pound per acre, did 

 not increase the effectiveness of the 0.25 pound treatments on washed plants. 



In laboratory tests conducted to determine the effectiveness of dieldrin 

 against boll weevils developing inside of squares, dieldrin killed many of the 

 developing forms. 



1950 - Ivy, E. E., Wm. Iglinsky, Jr., and C. F. Rainwater. Translocation of octamethyl 

 pyrophosphoramide by the cotton plant and toxicity of treated plants to cotton 

 insects and a spider mite. J. Econ. Ent. 43(5):620-626. 



Octamethyl pyrophosphoramide appeared to be highly specific for aphids and 

 mites. It did not kill the boll weevil, either as adults or as larvae developing in- 

 side squares of treated plants. 



1950 - Magee, W. J., and J. C. Gaines. Toxicity of Phosphorus Compounds to Various 

 Insects. J. Econ. Ent. 43(3):282, 284-285. 



Results of laboratory cage tests in which the toxicity of 7 new phosphorus 

 compounds were compared with parathion show that in general these newer com- 

 pounds were less toxic to most of the species of insects used. However, in a few 

 cases the toxicity of several of the newer compounds was equal to the toxicity of 

 parathion. It was noted that in some instances the higher dosages of the newer 

 compounds resulted in reduced toxicity. This is believed to be due to some 

 repellant action exerted by the insecticide at higher concentrations. 



The newer phosphorus compounds proved to be less toxic than parathion to 

 the boll weevil. 



Materials 3869 and 3901 were not effective in the control of either boll 

 weevils or bollworms under existing field conditions. 



1950 - Mistric, Walter J., Jr., and C. F. Rainwater. Laboratory experiements to deter- 

 mine the insecticidal action of several organic insecticides against boll weevil. 

 J. Econ. Ent. 43(6):892-898. 



Laboratory experiments were conducted at College Station, Tex., during 1949 

 to determine the specific components of insecticidal activity of the following in- 

 secticides and the 4 principal isomers of benzene hexachloride against the boll 

 weevil: (1) technical benzene hexachloride, (2) aldrin, (3) dieldrin, (4) toxaphene, 

 (5) chlordane, (6) 1,1-bis (p-chlorophenyl) 2-nitropropane, (7) 1,1-bis (p-chlor- 

 ophenyl) 2-nitrobutane, and (8) DDT. The components of insecticidal activity 

 determined were direct fumigating action, indirect fumigating action resulting 

 from plant fumigation, contact action, and combined action. 



Direct fumigating action was demonstrated to a marked degree for benzene 

 hexachloride, chlordane, aldrin, and dieldrin. Indirect fumigating action, that 

 resulting wholly from plant fumigation, was demonstrated for all primary 



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