being lower than the actual deposit present. This statement is based on the 

 calculated rate of loss per sampling period for each plot« With cue ■^-ceptio^. 

 of the two plots indicated above, the rate of loss of the original deposit foj/ 

 each plot agrees very well. 



The treatment of range grass with 4 and 6 oz. of naled per acre resulted 

 in low original deposits. The rate of loss of naled from the range grass was 

 rapid, with 78 percent of the original deposit lost in the first 24 hours and 

 95 to 99 percent lost in 3 to 7 days. 



When the residues from all treatments for any one insecticide were aver- 

 aged at each sampling time and the percentage of loss of the original average 

 deposit calculated, it was found that naled had the fastest rate of disappear- 

 ance. Diazinon and Bomyl were lost from the range grass at comparable rates, 

 followed by dimethoate and carbaryl with similar disappearance curves. 



SUMMARY 



Residue determinations of one carbamate, three chlorinated hydrocarbon, 

 and sight organic phosphate insecticides on red clover, lima bean straw, and 

 range grass were conducted over a period of 8 years. The toxicants were 

 applied as dusts, granules, and sprays (foliage). When red clover v/as treated 

 with aldrin, carbaryl, heptachlor, and toxaphene harvest residues ranged from 

 <0.10 p. p.m. to 0.47 p.p.m. - Lima bean straw treated with dimethoate, phorate, 

 and trichlorfon carried harvest residues of 0,10, 0.30, and 0,02 to 0.07 p„p,m., 

 respectively. Residues of 13.7 p.p.m. (average) were found on the azinphos- 

 methyl-treated lima bean straw, and from <0.12 to 0.61 p.p.m.. on disulfoton- 

 treated lima bean straw. Measurable residues of Bomyl, carbaryl, diazinon, 

 and dimethoate were found on range grass when sampled at varying intervals 

 after application. Where naled was applied, 95 to 99 percent of the zero day 

 residue had dissipated in 7 days. 



LITERATURE CITED 



(1) California Spray-Chemical Corp. 



1959. Analysis for dibrom residues. 7 pp. Richmond, Calif. 



(2) Cueto, Cipriano, Jr. 



1960. Colorimetric determination of dieldrin and its application to 

 animal fat. Jour. Agr. and Food Chem. 8:273-276. 



(3) Dickason, E, A., and Terriere, L. C. 



1961. Insecticide residues on red clover after clover root borer con- 

 trol with aldrin and heptachlor granules. Jour. Econ. Ent, 

 54(5): 1058-1059. 



(4) Dobson, R. C. , Thornberry, G. C. , and Belling, T. E, 



1960. Residues in established alfalfa treated with granulated phorate 

 and their effect on cattle fed the hay. Jour. Econ. Ent. 53(2); 

 306-310. 



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