Absorption and Degradation of Metalaxyl in Mustard Plant (Brassica juncea)

Absorption and degradation of metalaxyl were studied in mustard (Brassica juncea) plants after application as a seed dresser, a foliar spray, and a combination of both under subtropical conditions in India. Results indicated that absorption of metalaxyl increased up to 30 days when it was applied as a seed dresser; thereafter, it started declining and was not detectable after 60 days of sowing. The maximum residues (average, 9.03 ppm) of metalaxyl were found after 1 day of spraying. The dissipation of metalaxyl after initial deposits on mustard plants was almost complete after 15 days of spraying. The safe waiting period of metalaxyl was calculated to be 62 and 8 days for seed dresser and foliar application, respectively. The seeds raised through treatments under study were completely free from any detectable amount of metalaxyl residues.