Bioactivity of butene-fipronil and its field efficacy against diamondback mouth, Plutella xylostella L.

Chinese. 为系统地评价新药剂丁烯氟虫腈对小菜蛾的生物活性及环境因素对其应用效能的影响，在室内，建立了丁烯氟虫腈对小菜蛾幼虫的敏感毒力基线，测定了丁烯氟虫腈对小菜蛾卵的活性，测定了温度、龄期对其生物活性的影响以及对小菜蛾3龄幼虫的持效性，并进行了田间防治试验。结果表明，丁烯氟虫腈对小菜蛾具有较高的触杀毒力，48 h LD50为0.45μg/头。用64 mg/L丁烯氟虫腈药液浸渍，对小菜蛾卵的孵化抑制率为46.24%，且初孵幼虫存活率明显降低；丁烯氟虫腈对小菜蛾1～2龄幼虫的毒力较高，3龄以后随虫龄增大，敏感性降低；温度对丁烯氟虫腈毒力发挥有显著影响，表现明显的正温度系数效应，温度从15℃上升到32℃，毒力增强15.49倍。持效性试验表明，64 mg/L丁烯氟虫腈对小菜蛾3龄幼虫的校正死亡率在84%～95%之间，持效15天以上。田间试验结果表明，丁烯氟虫腈对小菜蛾具有较好防治效果，以5%丁烯氟虫腈乳油1200倍液施药，药后1天防效达76%以上，药后7天在88%以上，与相同用量的同类药剂氟虫腈无差异显著性。

English. In order to value the bioactivity and the effect of environment on the efficacies of butane-fipronil against Plutella xylostella L. by the numbers, the laboratorial egg-dipping, leaf-dipping, topical application bioassay and field trails were used in present paper. Meanwhile, susceptible toxicity baseline of Plutella xylostella to butene-fipronil was established with topical application method as well. Butene-fipronil displayed the better contact toxic to the larvae of diamondback mouth and the LD50 was 0.45μg/larva after treated 48 h by the topical method. The hatching rate of eggs and the survival rate of larvae were reduced, the control rate of hatching to Plutella xylostella was 46.24% with 64 mg/L concentration. The toxicity of butene-fipronil to Plutella xylostella deduced with the increase instar. 1st or 2nd instar larvae were the most sensitive stage by leaf dipping method. Temperature tests showed that the toxicity become greater as temperature ranged from 15℃ to 32℃, at 15-32℃, the toxicity of butene-fipronil to the larvae of Plutella xylostella increased by 15.49-folds. In addition, the mortality was 84%-95% and residual activity was over 15d at concentration of 64 mg/L treatment. The result of field trial demonstrated that the compound butene-fipronil was a predominant insecticide with rapider toxicity and keep a longer effectiveness than others against diamondback mouth.