between the insecticide distribution and fat 

 content. There was no apparent difference in 

 the distribution of the insecticide between the 

 dieldrin-resistant and dieldrin-susceptible boll 

 weevil. There was no difference in the penetra- 

 tion of the cuticle by the C 14 labeled dieldrin 

 between the resistant and susceptible boll wee- 

 vil at the single applied dosage. 



155. Shipp, 0. E., Lindquist, D. A., and 

 Brazzel, J. R. Characteristics of residues of 

 methyl parathion applied to field cotton. Jour. 

 Econ. Ent. 56: 793-798. 1963. 



Methyl parathion applied to field cotton by a 

 high-clearance spray machine at the rate of 0.5 

 pounds in 6 gallons of water per acre was found 

 to persist on and in the foliage up to 12 days. 

 The principal site of the residues was in and 

 under the cuticle of the leaf and not on the sur- 

 face. Residues found 1, 3, 7, and 12 days after 

 treatment were toxic to the weevil. 



Analysis of P 32 labeled methyl parathion in- 

 dicated the residual half-life of the insecticide 

 applied to cotton leaves was approximately 24 

 hours. Maximum penetration of the leaf by the 

 insecticide occurred within the first 2 hours 

 after application. The P 32 labeled methyl para- 

 thion was not translocated from its site of ap- 

 plication on the leaf. Most of the residual 

 deposit was located within the leaf tissues, with 

 some remaining in the cuticular layer of the 

 leaf. Four compounds containing P 32 were 

 found in the residue. Two were identified as 

 methyl parathion and methyl para-oxon. The 

 others were not identified. 



More of the residual parathion in the leaf 

 was converted to methyl para-oxon at high 

 temperatures (72°-112° F.) than at lower tem- 

 peratures (70°-90°). The toxicity of methyl 

 parathion residues over extended periods was 

 due in part to the presence of methyl para-oxon. 



156. Simpson, D. R., Bull, D. L., and Lind- 

 quist, D. A. A semi-microtechnique for the 

 estimation of cholinesterase activity in boll 

 weevils. Ent. Soc. Amer. Ann. 57: 367-371. 

 1964. 



Hestrin's colorimetric method was modified 

 to allow a consistent measurement of the com- 

 paratively low cholinesterase activity found in 

 the boll weevil. The technique yielded results 

 that were independent of the amount of insect 

 material present; and if the established limits 

 of the technique were not exceeded, the results 

 varied only slightly in consecutive analyses. 

 Sixty or more analyses often were made con- 

 currently. 



157. Smith, G. L., Cleveland, T. C, and 

 Clark, J. C. Boll weevil control with empha- 

 sis on early season and fall treatment in 1960, 

 1961, and 1962 at Tallulah, La. U.S. Agr. Res. 

 Serv. ARS 33-100. 1964. 



Results indicated that fall applications of 

 methyl parathion were effective in reducing 

 hibernating boll weevil populations. A 7-day 



application interval would probably be more 

 effective than a 10-day interval. Although con- 

 trol of overwintered boll weevils with Guthion 

 required a minimum of late-season treatment, 

 the best control was obtained when fall treat- 

 ment with methyl parathion was followed with 

 Guthion. This procedure would be more effec- 

 tive in reducing overwintered populations in 

 the boll weevil belt than fall treatment or early- 

 spring treatment alone. 



158. Smith, G. L., Cleveland, T. C, and 

 Clark, J. C. Cost of cotton insect control 

 with insecticides at Tallulah, La. U. S. Agr. 

 Serv. ARS 33-96, 7 pp. 1964. 



The boll weevil became resistant to the 

 chlorinated hydrocarbon insecticides in Loui- 

 siana in the midfifties. Until cotton growers 

 learned to cope with the situation control costs 

 ran as high as $60 per acre. ARS scientists 

 cooperated with local growers to obtain infor- 

 mation on cost and effectiveness of cotton in- 

 sect control programs. 



In 1957 the cost of insecticides and their ap- 

 plication was $38.22 per acre; in 1962 the cost 

 had decreased to $19.66. The yield of lint for 

 1957 and 1962 was 558 and 745 pounds, re- 

 spectively. 



159. Smith, G. L., Cleveland, T. C, and 

 Clark, J. C. Boll weevil movement from hi- 

 bernation sites to fruiting cotton. Jour. Econ. 

 Ent. 58: 357-358. 1965. 



From 1960 to 1963 groups of greenhouse- 

 grown cotton plants were placed in hibernation 

 sites, cottonfields, or adjacent soybeanfields or 

 grassfields to determine movement of boll wee- 

 vils from hibernation sites. Weevils were not 

 collected on plants in hibernation sites, but they 

 were found on plants 100 feet or more from 

 such sites, with greater numbers on plants in 

 cottonfields than in grassfields or soybeanfields, 

 even when cottonfields were farther away. 

 Temperature and rainfall greatly influenced 

 the numbers found. However, it was not pos- 

 sible to collect enough weevils by this method 

 to be of practical value in reducing overwintered 

 populations. 



160. Smith, G. L., Cleveland, T. C, and 

 Clark, J. C. Field tests for control of over- 

 wintered boll weevils. Jour. Econ. Ent. 58: 

 360-361. 1965. 



Resistance to chlorinated hydrocarbon insec- 

 ticides used individually against overwintered 

 boll weevils was evident; but certain mixtures, 

 such as toxaphene, Strobane, or endrin plus 

 DDT, and organophosphorus compounds gave 

 effective control when applied at the proper 

 time. 



161. Smith, G. L., and Scales, A. L. The 

 effect of air and ground surface temperature on 

 boll weevil winter survival. Jour. Econ. Ent. 

 58: 174-175. 1965. 



Records and observations indicated that very 

 little winter mortality of boll weevils results 



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