Degradation dynamics of quinalphos on cabbage under subtropical conditions of Ludhiana, Punjab, India

A study was undertaken to determine the disappearance trends of quinalphos residues on cabbage under subtropical conditions at Ludhiana. Single application of quinalphos was made @ 500 and 1000 g a.i. ha-1 on cabbage and samples were collected at intervals of 0 (1 h), 1, 3, 5, 7, 10 and 15 days after application. Average initial deposits of quinalphos on cabbage were found to be 0.41 and 0.75 mg kg-1 at single dose and double dosages, respectively. Residues of quinalphos dissipated below determination limit of 0.01 mg kg-1 in 7 and 10 days, respectively at single and double dose. The half-life of quinalphos on cabbage was observed to be 3.02 and 2.70 days for single and double dose, respectively. The study suggested a waiting period of 7 days for safe consumption of cabbage.