Di-Syston 
0,0-Diethyl $-(2-ethylthio) ethyl phosphorodithioate 
(C9H50) 2 ~P-S-CHp ~CHp ~S~CHp CH 
After intraperitoneal injection of labeled di-syston into rats, the 
rats were sacrificed and the livers analyzed. Di-syston sulfoxide, di- 
syston sulfone, di-syston-P=O sulfoxide and di-syston-P=0 sulfone were 
found. In the urine collected from treated rats, only hydrolytic products 
were identified; diethyl phosphate, diethyl phosphorothioate, diethyl 
phosphorodithioate, and inorganic phosphate. Four other compounds were 
observed but not identified. The di-syston phosphorothiolate derivate 
was not found (Bull, 1965). 
Di-syston-P2 was injected into bollworm larvae which were sacraficed 
at varying intervals. Di-syston sulfoxide and sulfone, di-syston-P=0 
sulfoxide and sulfone, inorganic phosphate, ethyl phosphate, diethyl 
phosphate, diethyl phosphorothiolate and several unidentified compounds 
were found. Examination of the excreta gave similar results. After 
exposure of tobacco budworms to labeled di-syston, the same products were 
found. However, the rate of metabolism of di-syston and its metabolites 
was greater (Bull, 1965). 
Cotton leaves and seedlings were treated with labeled di-syston. 
Initial oxidation of the 2-ethylthio ether was very rapid. After one day, 
di-syston sulfone was the major metabolite. After 16 days, the major 
metabolite was di-syston-P=0 sulfone. The only hydrolytic products found 
were inorganic phosphate, diethyl phosphate, and diethyl phosphorothioate 
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