Mechanism of Residue Loss of Hercules AC-528 Components on Plant Foliage1

Publisher Website
Google Scholar
Abstract
The acaricide and insecticide, Hercules AC-.528 (Delnav), is a mixture of the cis and trans isomers of 2,3-p-dioxanedithiol S,S-bis(O,O-diethyl phosphorodithioate) along with certain other phosphorodithioates. Loss of the Hercules AC-.528 components from plants resulted from volatilization, hydrolysis, and the formation of more polar derivatives and more potent anticholinesterase agents. The cis and trails isomers of Hercules AC-528 were similar in persistence so that the isomer ratio did not change during residue loss from that of the insecticide initially applied to the plants. No inter-conversion occurred on plants between the cis and trans isomers and the dioxene derivative, which is an impurity in the technical insecticide. The components of Hercules AC-528were only slowly hydrolyzed on the plant surface, but rapidly hydrolyzed when absorbed into the plants. Several of the components were converted to more polar derivatives and more potent anticholinesterase agents when applied to plants. This conversion may be due in part to the formation of phosphorothiolate derivatives. Attempts at chemical oxidation of certain components of Hercules AC-528 to yield the phosphorothiolate derivatives were only partially successful. Several components of technical Hercules AC-528 and certain non-hydrolyzed derivatives formed from the Hercules AC-528 components after application to plants are not determined by the residue analysis procedure of Dunn (1958). The toxicological significance of the organophosphates present in residues of Hercules AC-528 on crops but not determined by the colorimetric method of analysis cannot he fully evaluated with the limited data presented here.

This publication has 0 references indexed in Scilit: