Dissipation Behavior of a Mancozeb Residue (Dithiocarbamate Fungicide) in Tomato Under South Moroccan Climatic Condition

Dissipation behavior of mancozeb, a widely used dithiocarbamte fungicide, applied under field condition on tomato at recommended dose was undertaken under greenhouses and open field during October and March in Souss-Massa area (south of Morocco) climatic condition. Residue levels of mancozeb were determined by using a simple method consisting in a hot acid digestion of the whole sample to evolve carbon disulfide (CS 2 ), which is further quantified by spectrophotometry. Degradation rate in both open field and greenhouse followed first order kinetic. Half lives were 1.77 and 1.3 days in open field and in greenhouse were 2.0 and 1.8 days for October and March period respectively. Based on the observation reported, a pre harvested interval of at least three days after pesticide application at recommended dose may be suggested.