When P32-labeled dimethoate was applied to bollworm larvae and adult 
boll weevils (Bull et al., 1963b), metabolic products were similar to 
those reported for mammals. From internal extracts of topically treated 
boll weevils, seven metabolites were isolated and identified. Among these 
were dithioate, and the thiocarboxy and oxygen analogs of dimethoate, and 
what is believed to be the oxycarboxy analog. Bollworms were treated by 
injection of labeled dimethoate. The highly toxic oxygen analog was 
highest in concentration. Later, considerable amounts of dithioate were 
found. The metabolite of major importance which is found is dimethyl 
phosphate. This accumulates and breaks down slowly. The desmethyl 
carboxy derivative and what is thought to be monomethyl phosphate are 
also present. [In the locust, the main product is the highly toxic thio- 
late analog (Sanderson and Edson, 1964). 
When applied to plants, dimethoate was rapidly absorbed and decom- 
posed both on the surface and within the plant by hydrolysis and oxidation. 
On the plant surface, dimethoate underwent non-enzymatic oxidation to the 
oxygen analog and hydrolysis to water soluble derivatives identified as 
dimethyl phosphoric and 0,O-dimethyl phosphorothioic acids, desmethyl 
dimethoate, and a compound thought to be the oxycarboxy derivative. With- 
in plants, the oxygen, desmethyl, thiocarboxy and oxycarboxy analogs, mono- 
methyl and dimethyl dithioate, monomethyl and dimethyl thioate, dimethyl 
phosphate and phosphoric acid were found. Inside the plant the desmethyl 
analog was predominant, whereas, on the surface the oxycarboxy compound 
predominated. Marked quantitative differences found in the levels of the 
different water soluble derivatives in and on corn, cotton, olives, sugar 
90 
