Toxicity of O,O-diethyl O-carboalkoxyphenyl phosphorothionates to the imported fire ant

Some phosphorothionate imported fire ant toxicants with delayed kill

“…The toxicities of the bromo, alkoxycarbonyl substituted phosphorothionates (Table I) are lower than those of the bromoand alkoxycarbonyl compounds (Fisher et al, 1980) in vivo. Similarly, in an in vitro test, the molar concentration for 50% inhibition of fire ant brain AChE (Im) was 1.86 X 10"7 M for , -diethyl O-p-(isopropoxycarbonyl)phenyl phosphate and 2.21 X 10~7 M for , -diethyl O-2-bromo-4-(isopropoxycarbonyl)phenyl phosphate, indicating that the latter compound is the less active cholinesterase inhibitor.…”

“…The phosphorothionates 2a-e each contain both a bromine atom and a -C02Me or -C02-i-Pr group. These compounds were prepared because both monobromo (Lofgren et al, 1967;Wojcik et al 1973) and monoalkoxycarbonyl (Fisher et al, 1980) substituents on phosphorothionates showed good promise as IFA toxicants. Three of these compounds showed 100% kill after 14 days at 1%, but none of them showed delay.…”

“…Phosphorothionates (2). The mono-and disubstituted phenols (1) were then reacted with sodium carbonate in acetone followed by overnight reflux with diethyl phosphorochloridothionate and worked up by a previously reported procedure (Fisher et al, 1980). The IR and NMR spectra of each phosphorothionate 2 were consistent with its assigned structure.…”

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in laboratory tests but were not effective in the field (Banks et al, 1977); some analogous alkoxycarbonylphenyl compounds, especially those of low hydrophobicity, showed promise, but delay was inadequate (Fisher et al, 1980).

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“…Each toxicity test consisted of three replications at three concentrations, and the results of these tests are given in Table I. The method used to determine /«, values was given by Fisher et al (1980).…”