柞蚕饰腹寄蝇防治药剂氟虫腈酰胺衍生物的合成与筛选研究

Synthesis and Screening of Pesticides for Controlling Blepharipa Tibialis Chao, Fipronil Amide Derivatives

柞蚕饰腹寄蝇是一种毁灭性的柞蚕寄生害虫,其防治主要依赖于有机磷杀虫剂乐果,长期使用导致了抗药性问题。为筛选柞蚕饰腹寄蝇防治新药剂,以氟虫腈为母体化合物合成16种氟虫腈酰胺衍生物,采用熔点测试和~1H-NMR确认其结构;以四龄春柞蚕为试虫测定衍生物对柞蚕的毒性,在此基础上设置4个浓度梯度,测定寄生于五龄春柞蚕体内的柞蚕饰腹寄蝇的防治效果和药物处理对柞蚕产卵量和孵化率的影响。毒性试验结果表明:所合成的化合物对四龄春柞蚕的半致死浓度(LC_(50))范围为570~3998mg·L^(-1),其中13个化合物LC_(50)高于1000mg·L^(-1);所合成的氟虫腈酰胺衍生物毒性较氟虫腈(LC_(50)=182.2mg·L^(-1))大幅下降。防治效果试验表明:有8个衍生物在500mg·L^(-1)以下处理后,其营茧率高,其归一化柞蚕营茧率(即处理营茧率与空白营茧率之比)高于90%,且对柞蚕饰腹寄蝇的防效高于80%。对柞蚕产卵量和孵化率的影响调查数据表明:药物处理后单蛾产卵量及孵化率均与空白处理差异不显著,说明它们对柞蚕产卵量和孵化率无不良影响。在氟虫腈酰胺衍生物合成及其对四龄柞蚕毒力测定的基础上,首次发现8个化合物(XA01,XA04,XA06,XA08,XA09,XA10,XA13,XA16)在500mg·L^(-1)以下处理,柞蚕饰腹寄蝇防治效果较佳(防效>80%),对柞蚕相对安全(归一化营茧率>90%),且对柞蚕繁育无不良影响,具有蚕业应用价值。

Blepharipa Tibialis Chao is a destructive parasitic insect pest of tussah silkworm; its control mainly depends on an organophosphorus insecticide, dimethoate. The long-term application of dimethoate caused a drug-resistance problem. In order to screen new control agents for for B. Tibialis Chao, sixteen Fipronil amide derivatives(FADs)were synthesized by using Fipronil as parent chemicals, and the structures were confirmed by melting point test and^1H-NMR. The toxicity of FADs against the 4th instar spring tussah silkworm was evaluated. On the basis of toxicity data, four concentration gradients were used to assess the Control activity(CA) of FADs on B. Tibialis Chao inside the 5th instar of spring tussah silkworm, the effects of drug treatments on the amount of eggs produced per moth and the hatching rate of eggs were determined. Toxicity test results showed that the half lethal concentration(LC_(50)) of FADs against the 4th instar spring tussah silkworm ranges from 570 mg·L^(-1)to 3998 mg·L^(-1); of all, the LC_(50) of 13 FADs reach over 1000 mg·L^(-1). Compared with that of Fipronil(LC_(50)=182.2 mg·L^(-1)), the toxicity of FADs synthesized decreases significantly. The control effect test showed that 8 FADs exhibit high cocooning rate after no more than500 mg·L^(-1)treatments. Their Normalized Cocooning Rate(NCR) namely the ratio of tussah cocooning rate after treatment with FADs to that of blank treatment, was higher than 90%, meanwhile, the CA of B. Tibialis Chao was over 80%. The drug effects on oviposition amount and hatching rate experim ent showed that there's no significant difference in single moth fecundity and hatching rate between each treatment and blank treatment, suggesting that they have no adverse effects on fecundity and hatchingrate of tussah silkworm. Based on the synthesis of FADs and determination of their toxicity against the 4th instar larvae of tussah silkworm, it is first found that under no more than 500 mg·L^(-1)treatments 8 compounds XA01, XA04, XA06, XA08, XA09,XA10, XA13, XA16 have better B. Tibialis Chao control(CA >80%), relative safety for tussah silkworm(NCR >90%) and no adverse effects on silkworm breeding, which means they are much of application in sericulture production.