Photolysis and residue decline study of abamectin emulsifiable and microcapsules in soil and wheat

The residue decline of abamectin in 1.8% emulsifiable concentrate(EC) and 2% microcapsule suspension(CS) under UV radiation,in soil and seed coat of wheat were studied.The results showed that the declination rate of abamectin prepared with two different formulations under three environments followed the first-order kinetics,and compared with ES,the residue declination rate of abamectin CS was delayed under UV light.The half-life of abamectin EC and CS at the dosage of 5 mg/kg and 20 mg/kg were 88.86,157.52 and 22.14,82.51 d respectively in soil.In the seed coat of wheat,the residue of abamectin CS was higher than EC,so the former could have longer persistence in field.