Persistence Pattern and Waiting Periods for Some Insecticides on Pea Crop
The persistence pattern and waiting period for sprays of phosalone (0.05%), fenitrothion (0.05 and 0.1%). oxydemeton-methyl (0.03 an4 0.95%), endosulfan (0.05 and 0.1%) and carbaryl (0.125 and 0.25%) in/on pea was studied under field conditions. Dissipation of the insecticides fo(lowed the first order reaction (the rate of degradation or dissipation was proportional to the logari-thmic Concentration of insecticides). The persistence pattern was. in the order: endosulfan> carbaryl - fenitrothion > phosalone = oxydemeton-methyl. The minimum waiting periods for acceptable levels of tesidues 9n pods were estimated as 15, 25, 20, 10 and 15 days for phosalone, fenitrothion, oxydemeton-methyl, endosulfan and carbaryl respectively. In case of leaf, a waiting period of 15 days is suggested for both endosulfan and carbaryl treatments. At harvest, seed and straw samples did not contain detectable levels of the insecticides.