Insecticides on single seeds treated with liquid dressings

Abstract

Abstract A method for determining insecticide on seeds treated with liquid formulations by extraction and gas chromatography of the extract was devised and used to estimate the amount of the insecticide on single seeds. Eight solvents were tested for their ability to extract aldrin from wheat seeds treated with a liquid formulation. Acetone‐hexane was chosen for further investigation because in 24 hours at room temperature it extracted at least 95% of the aldrin from treated seeds. This solvent almost quantitatively extracted chlorfenvinphos and carbophenothion at room temperature and γ‐BHC at 45° in 24 hours, without extracting substances which interfere with gas chromatography of the insecticides. The amount of insecticide found on single seeds varied widely, in seeds dressed both in the laboratory with commercial preparations (range 4‐ to 7‐fold) and in 2 commercial plants (range 40‐ to 200‐fold).