稻螟赤眼蜂蛹期接触农药对其成蜂搜寻和寄生能力的影响

稻螟赤眼蜂Trichogramma japonicum是稻田中鳞翅目害虫重要的卵期寄生型天敌,为了规范稻螟赤眼蜂放蜂期农药的安全使用,利用卵卡浸渍法处理蛹期稻螟赤眼蜂,通过稻螟赤眼蜂室内飞行装置和单雌寄生法评估了蛹期5种非鳞翅目害虫靶标农药井冈霉素、三唑酮、吡蚜酮、印楝素、毒死蜱对稻螟赤眼蜂成蜂搜寻和寄生能力的影响。搜寻能力结果显示,在毒死蜱处理后稻螟赤眼蜂失去搜寻能力,三唑酮、吡蚜酮和印楝素处理对稻螟赤眼蜂的搜索行为无影响,但井冈霉素处理下稻螟赤眼蜂的飞行蜂比例为48.1%,显著低于对照处理的74.7%。寄生能力结果显示,毒死蜱处理对稻螟赤眼蜂高毒,能使稻螟赤眼蜂失去寄生能力;印楝素处理对稻螟赤眼蜂的寄生力和子代羽化率无显著影响;井冈霉素、三唑酮和吡蚜酮处理下稻螟赤眼蜂的寄生力分别为22.2、25.3和24.7,显著低于对照的27.4、31.1和29.6,但对子代羽化率无显著作用。表明印楝素对稻螟赤眼蜂安全,可以推广使用;井冈霉素、三唑酮和吡蚜酮对稻螟赤眼蜂的搜索能力(仅井冈霉素)和寄生能力有显著的削弱作用,应谨慎使用;毒死蜱对稻螟赤眼蜂高毒,在稻螟赤眼蜂放蜂期应该禁用。

Foraging and parasitism ability of Trichogramma japonicum exposed to pesticides at pupal stage

Trichogramma japonicum Ashmead is an important biological control parasitoid wasp of Lepidopteran eggs in paddy fields. For standardizing the safety usage of pesticides in T. janponicum releasing duration, the impacts of five non-lepidopteran pests target pesticides (validamycin, triadimefon, pymetrozine, azadirachtin and chlorpyrifos) on foraging and parasitism ability of T. japonicum were evaluated through laboratory flight unit for T. japonicum and individual female parasitism method. Foraging ability results showed that all T. japonicum lost foraging ability in chlorpyrifos treatment. Treatments of triadimefon, pymetrozine and azadirachtin did not impact the foraging ability of T. japonicum, but flyer proportion in validamycin treatment was 48.1%, which was significantly lower than 74.7% in control. Parasitism ability results indicated that chlorpyrifos showed high toxic to T. japonicum, which their parasitism ability. Azadirachtin did not significantly alter the fecundity and emerge rate of T. japonicum. The fecundity of the validamycin, triadimefon, pymetrozine treatments were 22.2, 25.3 and 24.7 respectively, which were significantly lower than 27.4, 31.1 and 29.6 in respective control treatments. However, the emergence rate was not significantly different between the validamycin, triadimefon, pymetrozine treatments and respective control treatments. The results indicated that azadirachtin was safe to T. japonicum and could be applied in T. japonicum release duration; validamycin, triadimefon, pymetrozine significantly impaired the foraging ability (only validamycin) and fecundity of T. japonicum, which indicated that they should be applied carefully; chlorpyrifos was high toxic to T. japonicum, so that should be forbidden during T. japonicum releasing.