八种常用杀虫剂对多异瓢虫不同虫态的安全性评价

Safety evaluation of eight commonly used insecticides on different stages of Hippodamia variegata(Goeze)

多异瓢虫Hippodamia variegata是新疆棉田优势捕食性天敌之一。为了明确棉田常用杀虫剂对多异瓢虫不同虫态期的毒性,采用药液浸渍法和滤纸接触法,分别测定了8种常用杀虫剂不同剂量下对多异瓢虫卵孵化率、蛹羽化率以及幼虫和成虫死亡率的影响。结果表明:阿维菌素对多异瓢虫卵和蛹的毒性最低,LC_(50)值分别为9.36和20.98 mg/L,对幼虫的毒性最高,LC_(50)值为4.68 mg/L;烯啶虫胺对多异瓢虫卵和蛹的毒性最高,LC_(50)值分别为1.16和1.02 mg/L;吡虫啉对多异瓢虫成虫和幼虫的毒性最低,LC_(50)值分别为665.50和460.51 mg/L;螺虫乙酯对多异瓢虫成虫的毒性最高,LC_(50)值为5.67 mg/L。经不同杀虫剂处理后,随着药剂剂量升高,多异瓢虫卵的孵化率和蛹的羽化率逐渐下降,死亡率逐渐升高。研究表明:吡虫啉、啶虫脒和吡蚜酮对多异瓢虫成虫安全;吡虫啉、氟啶虫酰胺和吡蚜酮对多异瓢虫幼虫安全;烯啶虫胺和螺虫乙酯对多异瓢虫卵、幼虫、蛹和成虫的安全性均较差。在棉田防治害虫时应考虑不施用或低剂量施用烯啶虫胺和螺虫乙酯,可适量施用吡虫啉和吡蚜酮,同时尽量避开天敌昆虫各虫态发生高峰期。

Hippodamia variegata(Goeze)is one of the dominant predatory natural enemies in Xinjiang cotton fields.In order to clarify the toxicity of eight commonly used insecticides in cotton fields to eggs,larvae,pupae,and adults of H.variegata,the effects of different doses of insecticides on the survival,hatching,and eclosion rate of H.variegata were measured by filter paper contact and dipping methods.The results showed that avermectin had the lowest toxicity to the eggs and pupae of H.variegata with the LC_(50) values of 9.36 and 20.98 mg/L,respectively,and the highest toxicity to the larva with the LC_(50) value of 4.68 mg/L.The highest toxicity of nitenpyram to the eggs and pupae was observed with the LC_(50) values of 1.16 and 1.02 mg/L,respectively.Imidacloprid showed the lowest toxicity to adults and larvae with the LC_(50) values of 665.50 and 460.51 mg/L,respectively.The toxicity of spirotetramat to adults was the highest with the LC_(50) value of 5.67 mg/L.After treatment with different insecticides,the hatching rate and eclosion rate of H.variegata gradually decreased with the increase of insecticide dose,and the mortality rate gradually increased.Imidacloprid,acetamiprid and pymetrozine were safe for adults of H.variegata.Imidacloprid,flonicamid,and pymetrozine were safe for the larvae of H.variegata.The safety of nitenpyram and spirotetramat was poor against eggs,larvae,pupae,and adults of H.variegata.In the control of pests in cotton fields,we should not apply or apply low doses of nitenpyram and spirotetramat,and appropriately apply imidacloprid and acetones.Try to bypass the occurrence peak period of each natural enemy insect state.