Studies on the Metabolism of Alphamethrin - A Pyrethroid Insecticide, in Mustard (Brassica Campestris Linn.)

The metabolism of alphamethrin has been examined in/on mustard plants grown and treated under field conditions. More than 92 per cent alphamethrin degraded within 15 days after foliar treatment and followed a biphasic profile of degradation. It dissipated at a faster rate during the initial days (0–7) with a half-life of 2.3–2.6 days while at a much slower rate later (7–28 days) with a half-life of 7.5–8.7 days. 2,2-Dichlorovinyl-2, 2-dimethylcyclopropane- carboxylic acid, 3-phenoxybenzyl alcohol, 3-phenoxybenzaldehyde and 3-phenoxybenzoic acid were identified as free metabolites at 13, 17 and 23 days after spray application. Glycosides of 2,2-dichlorovinyl-2, 2-dimethylcyclopropanecarboxylic acid, 3-phenoxybenzyl alcohol and 3-phenoxybenzoic acid with D-glucose as the glycone were implied as conjugates.