沙蚕毒素类农药对美洲斑潜蝇的防治效果研究

STUDIES ON THE EFFICACY OF NEREINTOXINS FOR THE CONTROL OF THE VEGETABLE LEAFMINER Liriomyza sativae (Diptera: Agromyzidae)

测定了沙蚕毒素类农药杀虫单、杀虫双、易卫杀、多噻烷、巴丹对美洲斑潜蝇各龄幼虫、雌成虫的毒力，进行了成虫取食忌避试验和田间小区试验结果表明：（１）美洲斑潜蝇１、２、３龄幼虫对杀虫单最敏感，其ＬＣ５０分别是０．１０６１、０．１２６４、０．１６００ｇ／Ｌ，其毒力回归曲线斜率分别是：７．９７８０、６．９５６１、５．１８６４美洲斑潜蝇幼虫对沙蚕毒素类农药以１龄最敏感，３龄幼虫对该类农药的ＬＣ５０是１龄的１．５～２倍田间用０．４５ｇ／Ｌ杀虫单喷雾第３和第６ｄ后，其校正虫口减退率分别为９２．０７％和９１．６６％，防治效果最显著；（２）沙蚕毒素类农药在施药前期３ｄ内对１龄幼虫有抑制作用，６ｄ后作用消失，说明其防效期不长。

The toxicities of nereintoxins mehypo, dimehypo, thiocylam, duosaiwan and cartap to the larvae and adults of female of Liriomyza sativae Blanchard were studied.Experiments for adults eating repellent were carried out in laboratory and field.It was found that the LC 50 of the first, 2nd and 3rd instars larvae for mehypo were 0.106 1, 0.126 4 and 0.160 0 g/L respectively, and the slopes of the LC-P regression lines were 7.978 0, 6.956 1 and 5.186 4, respectively. This indicated that the larvae of L.sativae Blanchard were more sensitive to mehypo than to other nereintoxins.The first instar larvae of L. sativae Blanchard for nereintoxins was the most sensitive to the toxins than other instars,the LC 50 of the 3rd instar larvae for nereintoxins was 1.5～2 fold compared with that of the first instar larvae. The results from field trails showed that the efficacy of mehypo for the control of L.sativae Blanchard was significantly different from other nereintoxins,3 and 6 days after spraying with 0.45 g/L mehypo,the population of the pest reduced to 92.07% and 91.66% respectively.The first instar of the larvae was inhibited by nereintoxins in 3 days after spraying, but no effect after 6 days.