Pyrethroids


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Pyrethroids

 

synthetic esters of chrysanthemumic acid; analogs of pyrethrins.

Pyrethroids are obtained either by the reaction of chrysanthemumyl chloride with an alcoholic moiety in the presence of a tertiary amine or by transesterification of the ethyl ester of chrysanthemumic acid in the presence of sodium. The pyrethroids that are most toxic to insects are esters of cyclopentenolones, of substituted benzyl alcohols, and of N-hydroxymethylimides.

Pyrethroids produced today include allethrin (2-allyl-3-meth-yl-2-cyclopenten-4-oI-l-onyl chrysanthemumate), furethrin (2-furfury 1 -3-methyl -2- cyclopenten - 4 -ol -1 - ony 1 chrysanthemum-ate), cyclethrin (2-cyclopentenyl-3-methyl-2-cyclopenten-4-ol-1 -onyl chrysanthemumate), barthrin (6-chloropiperonyl chrysanthemumate), dimethrin (2,4-dimethylbenzyl chrysanthemumate), and tetrametrine [N-(3,4,5,6-tetrahydrophthalimido)-methyl chrysanthemumate]. These compounds, usually in the form of aerosols, are used against household insects.

REFERENCES

Mel’nikov, N. N., and K. D. Shvetsova-Shilovskaia. “Sintez insektitsidov piretrinovogo riada.” Khimicheskaia promyshlennost’, 1955, no. 3, pp. 50–61.
Volkov, Iu. P., and N. F. Shugal. “Sinteticheskie analogi piretrinov. Khimicheskaia promyshlennost’, 1969, no. 9, pp. 14–19.
Chemie der Pflanzenschutz- und Schädlingsbekä mpfungsmittel, vol. 1. Edited by R. Wegler. Berlin, 1970. Pages 87–102.

K. D. SHVETSOVA-SHILOVSKAIA

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We found the sam pyrethroids in the breeding sites as in th fields, and we concluded that these small doss in the water are the source of resistance slection in this area," says Aristide Hien, an ntomologist who recently compared pesticid contamination and resistance levels in sectins of Dano growing conventional verss organic cotton.
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