环保型25.15%印、硫种衣剂的研制及其活性效应测定

 根据胶体稳定原理和高分子聚合物成膜原理及流变理论,选取无毒的植物源农药印楝素和基本无毒的硫磺为杀虫杀菌剂活性组分,再配以有关助剂,研制出了环保型25.15%印硫种衣剂。用玉米小斑病菌(Bipolaris maydis)做印、硫种衣剂防病方面的配方筛选,结果认定:25.15%印、硫种剂的印、硫比以1∶124.8和1∶166.7为好,以1∶124.8为最佳配方。用孢子萌发法对选出的最佳配方(印:硫＝1∶124.8)进行毒力测定,对小斑病孢子发芽的毒力回归方程为y＝0.561 2＋1.493 3x,r＝0.966 1,LC₅₀为938.592 mg／L,LC_0.95＝816.394 4～1 079.195 2 mg／L,经卡方检验结果说明回归符合实际。根据N A Mansour法求出“协同毒力指数”(c.f)为＋10.32,表明混剂属相加作用(addition)。田间药效试验:用重庆地区玉米茎腐病主要病原瓜果腐霉菌(Pythium aphanidernatum)人工接种试验,用25.15%印、硫种衣剂药种比1∶40,1∶50,1∶60比例包衣玉为种子,田间出苗率依次为94.0%,96.5%,92.0%,相对防效分别为80.24%,79.46%和75.90%,前二者与后者差异显著(P＜0.05)。

Preparation and Activity Test of 25.15% Azadirachtin and Sulphur Seed Coating Agent

It is well known that Azadirachtin is a famous biological pesticide and sulphur almost has no toxicity to human being, so they are chosen as main active agents in the new eco-friendly pesticide:25.15% Azadirachtin and sulphur seed coating agent. In screening test against Bipolaris maydis. 3 agents were prepared according to 3 ratios of azadirachtin to sulphur, including 1 to 250.5, 1 to 166.7 and 1 to 124.8. The results showed that efficacy of the agent 1 to 124.8 was the best, then 1 to 166.7, and last 1 to 250.5. Therefore, the agent of 1 to 124.8 was adopted to do the following experients. In the laboratory bioassay against B. maydis, the toxicity was y=0.561 2+1.493 3 x, the coefficient of correlation 0.9661, LC₅₀＝938.5925 mg/L, and LC_0.95=816.394 4～1 079.1952 mg/L, X²-test showed that the equation is accordance with reality. In the field trail, corn seeds were coated at 3 weight ratios of pesticide to seed,namely, 1 to 40, 1 to 50 and 1 to 60. The results indicated that the emergence rates of seedlings were 94.0%, 96.5% , and 92.0%, and the effecacies against Pythium aphanidernatum were 80.24%, 79.46% and 75.90%, respectively.