矿物油乳剂对烟蚜茧蜂的安全性评价

【目的】矿物油乳剂因其安全性好、杀虫谱广、不易产生抗性等优点,被广泛用于果蔬、农作物、园林害虫的防治,但有关其对害虫天敌烟蚜茧蜂的安全性尚不明确。因此,本文研究矿物油乳剂对烟蚜茧蜂不同发育阶段的安全性,为更好地协调蚜虫的化学防治和生物防治提供理论依据。【方法】在实验室条件下采用药膜法和浸渍法测定了不同浓度(150、250、350、450倍液)矿物油乳剂对烟蚜茧蜂各发育阶段的影响。【结果】矿物油乳剂对烟蚜茧蜂成虫的影响较小,无明显胃毒作用,但有一定的触杀作用,以最高浓度150倍液(4986.960 mg·L-1)处理24 h后的存活率依然高达92%;矿物油乳剂对烟蚜茧蜂寄生蚜有较高的致死率,LC50为859.541 mg·L-1,该浓度远远低于此次供试的最低浓度450倍液(1662.320 mg·L-1),说明矿物油乳剂对烟蚜茧蜂卵和幼虫的安全性较差;矿物油乳剂对烟蚜茧蜂蛹期羽化率的影响较显著,处理组的僵蚜与对照组的僵蚜相比,羽化高峰期均滞后1 d,且羽化率随着处理浓度的增大而下降(450倍液时羽化率为81.25%,150倍液时仅为47.75%)。【结论】当蚜虫发生严重时,可考虑在烟蚜茧蜂成虫期协调使用矿物油乳剂进行联合控制,但矿物油乳剂的使用浓度和施用时间还有待进一步确定。

The effect of mineral oil emulsion on the natural enemy Aphidius gifuensis(Hymenoptera:Aphidiidae)

Aim] Mineral oil emulsion is widely applied for pest control on fruits, vegetables, crops and gardens because of low human toxicity, broad insecticidal spectrum and lack of resistance. However, there are few reports about the effect of mineral oil emulsion on natural enemies. Information on the safety of mineral oil emulsion on natural enemies in different development stages can provide abasis for better coordination of chemical and biological control methods.Method] Residual film method and dipping method were adopted under laboratory condition to determine the impacts of mineral oil emulsion on the hymenopteran natural enemy, Aphidius gifuensis in different development stages.Result] Mineral oil emulsion had little influence on adult A. gifuensis, without obvious toxicity when consumed, but with a certain contact toxicity. Under the highest treatment concentration of 150 dilution multiple liquid (4986.960 mg·L^-1), modify the survival rate was 92% after 24 h. The oil emulsion can cause higher mortality to eggs and larvae of A. gifuensis with the LC₅₀ being 859.541 mg·L^-1, which is much lower than the lowest tested concentration of 450 dilution multiple liquid (1662.320 mg·L^-1). Compared to the control group, the parasitoid emerged from emulsion-treated mummified aphids 1 day later, and the emergence rate decreased with the increasing treatment concentration, from 81.25% at the 450 dilution multiple liquid to 47.75% at 150 dilution multiple liquid.Conclusion] Mineral oil emulsion can be used when adult A. gifuensisare present, but its specific concentration and application time remain to be determined further to minimise damage to immature stages of this natural enemy.