

phosphate. This accumulated and degraded slowly. The desmethyl carboxy 
derivative and what was thought to be monomethyl phosphate were also 
present (1266). In the cotton leafworm (Prodenia Litura F), dimethoate 
gave rise to the oxygen analog, carboxy derivative, dimethylphosphoro- 
thioate, dimethyl phosphorodithioate, mono- and di-methyl phosphate, 
orthophosphate and thiophosphate (1636). 
Metabolism of dimethoate by the American cockroach (Periplaneta 
americana L.), the German cockroach (Blatella germanica L.), and the 
house fly (Musca domestica L.) was qualitatively similar to that of rats. 
Quantitative differences were observed (167, 1039). 
Studies have been conducted with other insects. In the locust, the 
main product was the highly toxic thiolate analog (dimethoxon) (1266). 
Using the green rice leafhopper (Nephotettix cincticeps Uhler), the mono- 
and di-methylphosphates and orthophosphate were observed. Homogenates of 
houseflies, 4th to 5th instar larvae of rice stem borer (Chilo Suppressalis 
Walk.), adults of apterous form of green peach aphid (Myzus persicae Sulzer) 
and adult male American cockroaches degraded dimethoate. Desmethyl dimethoate, 
the carboxy acid analog and dimethyl phosphorothioate were identified (1039). 
When applied to plants, dimethoate was rapidly absorbed and decomposed 
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 0,0-dimethyl phosphorothioic acids, desmethyl dimethoate, 
and a compound thought to be the oxycarboxy derivative. Within plants, the 
oxygen, desmethyl, thiocarboxy and oxycarboxy analogs, monomethyl and di- 
methyl dithioate, monomethyl and dimethyl thioate, dimethyl phosphate and 
phosphoric acid were found. Inside the plant the desmethyl analog was pre- 
dominant, 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 beets, cucumbers, 
and potato plants indicated different paths of degradation (341, 597, 842, 
1107, 1268, 1269, 1270, 1271, 1272). 
In a pot test, p32_dimethoate was applied to onions. After six days 
only dimethoate and (CH30)2P(0)SCH)CONHCH3 (in a 6:1 ratio) were observed 
(1107). Rice and apple leaves degraded dimethoate to desmethyl dimethoate, 
dimethyl phosphate and orthophosphate. With in vitro studies, cabbage leaves 
gave rise to desmethyl dimethoate, the carboxy acid analog and dimethyl 
phosphates; with rice leaves, the desmethyl analog was identified (1039). 
161 
