gave much better control of the boll weevil and the cotton fleahopper ( Psallus 

 seriatus (Reut.)) than dieldrin or toxaphene. Toxaphene was more effective 

 than Strobane (mixture of chlorinated terpenes with about 66% of chlorine) 

 against thrips ( Frankliniella sp.), but both materials gave poor control of cotton 

 fleahoppers and boll weevils. In mixtures with DDT the materials were equally 

 effective against these pests. Sevin (1-naphthyl methylcarbamate) in a wettable- 

 powder formulation was effective against thrips, cotton fleahoppers, and boll 

 weevils, but rains occurring a short time after application reduced its effective- 

 ness. Shell SD 4402 (1 ,3,4,5,6,7,8,8-octachloro-3a,7,7a-tetrahydro-4,7- 

 methanophthalan), Shell SD 3562 (dimethyl l-(dimethylcarbamoyl)- l-propen-2-yl 

 phosphate), Bayer 25141 (0,0-diethyl O-(p-methylsulfinyl) phenyl phosphor o- 

 thioate), and dimethoate were as effective as dieldrin in thrips control. 



I960 - Pfrimmer, T. R„, E. P. Lloyd, M. E. Merkl, and R. E. Furr. Field experiments 

 with several insecticidal sprays against the boll weevil and bollworm. J. Econ. 

 Ent. 53(5):711-714. 



In experiments at Stoneville, Miss., in 1957 and 1958, a Guthion-DDT mixture 

 gave outstanding control of the boll weevil. Sevin (1-naphthyl methyl-carbamate), 

 toxaphene-malathion, dicapthon, Bayer 29493 (0,0-dimethyl 0-(4-methylthio-m- 

 tolyl) phosphorothioate), and mixtures of Monsanto CP 7769 (hexaethyl (ethylthio- 

 methylidyne) triphosphonate), methyl parathion, toxaphene, or malathion with DDT 

 gave generally satisfactory control, but Thiodan (6,7,8,9, 1 0, 10-hexachloro- 1,5, 

 5a,6,9,9a-hexahydro- 6,9-methano-2,4,3-benzodioxathiepin-3-oxide), ronnel-DDT, 

 toxaphene, and endrin were not effective. The mixture of DDT with ronnel, 

 Monsanto CP 7769, Guthion (0,0-dimethyl S-(4-oxo- l,2,3-benzotriazin-3-(4H)- 

 ylmethyl) phosphorodithioate), methyl parathion, and malathion were effective in 

 controlling the bollworm (Heliothis zea (Boddie)). 



i960 - Tsao, Ching H„, and G. T. Bottger. Laboratory studies on the effectiveness of 

 Chipman R-6199 against some cotton pests. J. Econ. Ent. 53(1 ):103- 106. 



Chipman R-6199, the monohydrogen oxalate of 0,0-diethyl S-(2-diethyl- 

 amino)-ethyl phosphorothioate, was tested against insects introduced on potted 

 cotton plants held in the laboratory. At 5 mg. per plant it was effective against 

 adults of the boll weevil, but the residual effect was short-lived. 



I960 - Tsao, Ching H., and W. L. Lowry. Factors affecting the tolerance of boll 

 weevils to calcium arsenates. J, Econ. Ent. 53(5):844-847. 



Boll weevils emerged from cotton bolls were more tolerant to tricalcium 

 arsenate than those emerged from squares. Their wet weight and fat content 

 were also greater. When field-collected weevils were exposed to calcium 

 arsenate in petri dishes, with or without cotton squares for food, the insects 

 that died first had lower body weight and fat content than those that died later. 

 Tricalcium arsenate and commercial calcium arsenate were found to kill weevils 

 when ingestion of the poisons was made impossible, but their effectiveness was 

 reduced by half. Weevils treated with calcium arsenates lost weight more 

 rapidly under desiccation than untreated live or dead weevils. The mortality of 

 treated insects decreased as the humidity increased, but that of untreated in- 

 sects showed little difference. These results indicate that under field conditions, 

 when the evaporation rate is higher than that in the laboratory, the desiccating 

 action of calcium arsenates may be responsible for partial control of the insects. 



I960 - Walker, J. K., Jr., and R. L. Hanna. Control of boll weevils resistant to 

 chlorinated hydrocarbons. J. Econ. Ent. 53(2):228-231 . 



During 1956, 1957, and 1958, 15 replicated field-plot insecticide-comparison 

 experiments were conducted in the Robertson-Burleson County area of south- 

 central Texas, to determine the effectiveness of various insecticides for control 

 of boll weevils resistant to chlorinated hydrocarbon insecticides. Guthion 

 (0,0-dimethyl S-(4-oxo- 3H- 1 ,2,3-benzotriazine- 3-methyl) phosphorodithioate), 

 Sevin (1-naphthyl methylcarbamate), and calcium arsenate dust were most ef- 

 fective in controlling these weevil populations. Methyl parathion and malathion 



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