Pesticide Residues, Residual Properties of the Systemic Insecticide O,O-Dimethyl 1-Carbomethoxy-1-propen-2-yl Phosphate

Abstract

This investigation was supported in part by research grants from the Shell Development Co. and the Division of Biology and Medicine,

The metabolism and degradation of vinyl phosphate insecticides

“…Methods have also been deseribed for tetraehlorvinphos alone (F AHEY et al 1969, BEBOZA 1966 and include Harne-photometrie deteetion (SHEBMAN and HERRICK 1971 (22a) trans-crotonate structure (22b) Mevinphos (22) In referring to the isomers it is preferable to name them as the E or Z isomers or as cis-crotonate or trans-crotonate. This is particularly desirable with these compounds since the first configurations that were assigned (CASIDA et al 1956, SPENCER et al 1958 were opposite to those above (22a and b) which are now considered to be correct (STU.ES et al 1961, STOTHERS and SPENCER 1961, FUKUTO et al 1961. In addition, the convention used by the earlier workers was different so that they assigned the wrong structure to the isomers but used the same names (cis-or trans-) for the respective isomers as those given by STU.…”

“…It was proposed that the significant reduction in residues was a function of the volatility of the compound. The first study of the metabolism of the compound on foliage was reported by CASIDA et al (1956) a Chemical name: dimethyl 2-methoxycarbonyl-l-methylvinyl p'hosphate (IUPAC) or l-carbomethoxy-l-propen-2-yl dimethyl phosphate, or methyl 3-(dimethylphosphoryloxy) but-2-enoate, or methyl 3-(dimethoxyphosphinyloxy) crotonate.…”

“…The P-OH carboxy acid (25) was identified as a metabolite of the carboxy acid (23) in peas and was formed from it at a rate similar to that of dimethyl phosphate. CASIDA et al (1956) suggested that the carboxy acid (23) was the first step in the metabolism of mevinphos in plants. However, SPENCER and ROBINSON (1960) indicated that if the carboxy acid (23) were an essential step in the degradation in the plant then the P-OH carboxy acid (25) formed from it would also have been isolated as adegradation product of mevinphos itself.…”

“…In early studies, CASIDA et al (1956) showed that 90 percent of the applied mevinphos was lost in the field in an average of 1.7 days (0.8 to 4.2 days) on a range of crops and 99 percent of the initial residues of mevinphos were lost in 3.9 days. In later studies (COFFIN and McKINLEY 1964), it was shown that residues of mevinphos on lettuce had fallen to less than 0.1 p.p.m.…”

“…The uptake of mevinphos by plants from the soil has been weIl established. Following surface applications of mevinphos to SeId soils at 0.25 lb./A (CASIDA et al 1956) residues in cabbages were 0.56 p.p.m. and in snap beans 1.7 p.p.m.…”