短期高温预处理与氟虫腈对小菜蛾3龄幼虫的联合作用
Interaction between short-term heat pretreatment and fipronil on diamondback moth Plutella xylostella (Linnaeus)
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摘要: 研究了短期高温预处理与氟虫腈对小菜蛾Plutella xylostella (Linnaeus)3龄幼虫的联合作用。结果表明, 短期高温对氟虫腈毒力的影响随高温水平及持续时间不同而不同。30 ℃预处理2 h或4 h对试虫有一定保护作用, 能够降低其后的氟虫腈毒力, 但8 h对试虫保护作用较弱且不稳定；35 ℃预处理2 h或4 h, 对试虫保护作用较强, 能够降低氟虫腈毒力, 但持续时间为8 h, 则会提高氟虫腈的毒力；40 ℃预处理2 h, 对试虫保护作用较弱且不稳定, 持续4 h便只表现为不利作用。协同毒力指数可应用于Hormesis效应评价。 研究了短期高温预处理与氟虫腈对小菜蛾Plutella xylostella (Linnaeus)3龄幼虫的联合作用。结果表明, 短期高温对氟虫腈毒力的影响随高温水平及持续时间不同而不同。30 ℃预处理2 h或4 h对试虫有一定保护作用, 能够降低其后的氟虫腈毒力, 但8 h对试虫保护作用较弱且不稳定；35 ℃预处理2 h或4 h, 对试虫保护作用较强, 能够降低氟虫腈毒力, 但持续时间为8 h, 则会提高氟虫腈的毒力；40 ℃预处理2 h, 对试虫保护作用较弱且不稳定, 持续4 h便只表现为不利作用。协同毒力指数可应用于Hormesis效应评价。Abstract: The interaction between short-term heat pretreatment and fipronil on 3rd instar larvae of diamondback moth Plutella xylostella (Linnaeus) was investigated. The results indicate that the effect of interaction between short-term heat pretreatment and fipronil on the insects varies with temperature and duration of heat-pretreatment. Heat pretreatment at 30 ℃ for 2 or 4 h can somehow protect insects from fipronil. However, the level of protection is low and unstable as the 30 ℃ pretreatment lasts for 8 h. At 35 ℃, the protection effect is observable in pretreated insects for 2 or 4 h, though 8 h pretreatment improves fipronil toxicity. At 40 ℃, only weak and unstable protection effects are noticeable at 2 h pretreatment duration. Harmful effects develop when the pretreatment is extended to 4 h. Cooperative virulence index (c.f.) may be adopted in Hormesis assessment.
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