Microcapsulating and Control Efficacy of Chlorpyrifos·Beta-cypermethrin on Grubs(Anomala corpulenta)

The preparation of chlorpyrifs·beta-cypermethrin capsules suspension(CS) by in-situ polymerization was introduced,the influence of the surfactant on microcapsulating process and the control efficacy of this product on the grubs(Anomala corpulenta Motsch)were investigated. The results indicated that SUR-1(the equal ratio mixture of saponin and gelatin) was the best surfactant to prepare chlorpyrifos·beta-cypermethrin capsules suspension. When the mass percent concentration of SUR-1 was 0.2%,the uniform microencapsules with satisfied diameter and wall thickness were obtained,and the encapsulating rates of two pesticides were above 98%,however,when the mass percent concentration of SUR-1 was increased to 0.4%,the encapsulating rates of chlorpyrifos and beta-cypermethrin decreased to 74.2% and 68.1%,respectively,and the release rates of two pesticides also decreased obviously. The field trials showed when the treated dose was 600 g(a.i. )/hm2 that the control efficacy of the 20% chlorpyrifos·beta - cypermethrin CS on the grubs was still above 70% 60 days after treatment.Meanwhile,chlorpyrifos EC and beta-cypermethrin EC were degraded rapidly in the soil,when the treated doses of the two products were 1 440 and 33.75 g(a.i. )/hm2, respectively.The control efficacy on the grubs were only 32.3% and 2.5% 60 d after treatment.