*Department of Entomology, Punjab Agricultural University, Ludhiana – 141004
Department of Plant Pathology, Punjab Agricultural University, Ludhiana – 141004
National Symposium on Strategic Issues in Plant Pathological Research held at Department of Plant Pathology, CSK HP Krishi Vishvavidayalaya, Palampur on November 24–25, 2011
Dissipation of metalaxyl and mancozeb in tomato was studied following four application of a combination formulation Ridomil MZ (metalaxyl + mancozeb) @ 0.25 and 0.50 per cent at 10 days interval. Residues of metalaxyl and mancozeb in tomato were estimated by gas liquid chromatography (GLC) and carbon disulphide (CS2) evolution method. Half- life periods for metalaxyl were found to be 1.29 and 0.41 days whereas for mancozeb these values were observed to be 3.76 and 4.14 days at single and double the application rates, respectively. Residues of metalaxyl dissipated below the limit of quantification (LOQ) of 0.02 mg kg−1 after 3 and 5 days at single and double the application dosage, respectively. Similarly, residues of mancozeb took 10 and 15 days to reach LOQ of 0.25 mg kg−1, at single and double dosages. Since both mancozeb and metalaxyl are present in Ridomil MZ fungicide so, the safe waiting period (WP) of 3 days for Ridomil MZ in tomato was suggested.
