阿维菌素预处理与短期高温对小菜蛾3龄幼虫的联合作用

Interaction between avermectin pretreatment and subsequent short-term heat treatment on 3rd diamondback moth instar larvae (Plutella xylostella)

以试虫死亡率、化蛹时间、化蛹率、羽化率等的变化为依据研究了阿维菌素预处理与短期高温对小菜蛾(Plutella xylostella)3龄幼虫的联合作用。结果表明:35℃、40℃高温持续4h及其以上时,对小菜蛾3龄幼虫具有显著不利影响,表现在试虫死亡率显著提高,化蛹率、羽化率显著降低;与35℃相比,40℃处理后试虫不利作用出现时间提前,化蛹时间显著推迟;0.56mg·L-1阿维菌素处理后,35℃持续12h能够显著提高阿维菌素的毒力;0.14mg·L-1、0.56mg·L-1阿维菌素均能显著提高试虫耐35℃持续4h、8h的能力。40℃持续2h以上都能显著提高0.14mg·L-1、0.56mg·L-1阿维菌素的毒力。0.14mg·L-1阿维菌素能够显著降低试虫耐40℃持续8h的能力,而0.56mg·L-1阿维菌素能够显著削弱试虫耐40℃持续2h、4h、8h的能力。

Interaction between avermectin pretreatment and subsequent short-term heat treatment on the 3rd diamondback moth （Plutella xylostella） instar larvae was investigated based on changes in mortality rate, pupation time, pupation rate, eclosion rate and adult emergence rate. When temperatures are set at 35 ℃ or 40 ℃ for 4 h or longer, tested insects exhibit negative effects such as significant increase in mortality rate and decrease in pupation and eclosion rates, adult emergence rate. Compared with 35 ℃, the negative effects at 40 ℃ appear earlier while pupation time delays. 0.56 mg·L^-1 avermectin toxicity significantly improves after 35 ℃ treatment for 12 h. Meanwhile heat tolerant ability of the insects to 35 ℃ treatment for 4 h or 8 h significantly improves by pretreatment with avermectin at 0.14 or 0.56 mg·L^-1. However, avermectin toxicity at 0.14 or 0.56 mg·L^-1 can significantly improve by short-term follow-up heat treatment at 40 ℃ for 2 h or longer. The tolerant ability of the insects to short-term heat treatment at 40 ℃ for 8 h is significantly weakened by pretreatment with avermectin at 0.14 mg·L^-1. 0.56 mg·L^-1 avermectin can weaken insect tolerance to short-term heat treatment at 40 ℃ for 2 h, 4 h or 8 h.