4种新型杀虫剂对黄色羽摇蚊(Cihronomu fslaviplumus)老熟幼虫的急性毒性

Acute Toxicity of Four New Types of Insecticides to the Fourth Instar Larvae of Chironomus flaviplumus Tokunage(Diptera:Chironomidae).

测定了峰升(15%杀单.唑磷乳油)、稻卫(20.2%阿维.唑磷乳油)、蚜螨克星(1.8%阿维.吡乳油)和蔬卫(2.4%高氯.阿维乳油)4种新型杀虫剂对黄色羽摇蚊(Chironomus flaviplumus)老熟幼虫的急性毒性。结果表明:峰升处理黄色羽摇蚊幼虫后24 h,不同浓度间的存活率无显著差异,而在其他时间段(48、72、96 h),随着杀虫剂浓度的增加,存活率逐渐下降。其他3种杀虫剂处理黄色羽摇蚊幼虫4 d,随着杀虫剂浓度的增加,每天的存活率也呈下降趋势。峰升、稻卫、蚜螨克星和蔬卫对黄色羽摇蚊幼虫48 h的LC50分别为0.173 5、0.024 9、0.001 5和0.004 6 mg.L-1。蚜螨克星毒性最高,毒性在同一数量级的还有蔬卫,其次为稻卫。峰升毒性最低,但仍属高毒杀虫剂。

Acute toxicity of four new types of insecticide （15% monosultap-triazophos EC, 20.2% avermectin-triazophos EC, 1.8% avermectin-imidacloprid EC and 2.4% beta-cypermethrin-avermectin EC） was evaluated by using fourth instar larvae of dipteran Chironomus flaviplumus Tokunage of the Chironomidae family. Results show that 48 h acute toxicity of 1.8% avermectin-imidacloprid EC was the highest （ LC50 =0. 001 5 mg · L^-1 ） among the four insecticides. Concentration had significant effects on survival rates of Chironomus flaviplumus Tokunage larvae except for 15% monosuhap-triazophos EC （24 h toxicity）. For each insecticide, the differences in survival rates of chironomid larvae between 24, 48, 72 and 96 h were significant. For each day, the effects of the four insecticides on larvae were also significant. In conclusion, survival of chironomid larvae was severely affected by these insecticides. The patterns of action of the four insecticides were different, too. Larvae exposed to 15% monosultap-triazophos EC died slowly within four days but died much quicker when exposed to the other three insecticides. The serious impacts of insecticides on chironomid larvae in this study may help promote monitoring and assessing water quality in China.