大环内酯类新化合物天维菌素杀螨活性及田间防治效果

为明确新化合物天维菌素的杀螨活性,采用叶碟喷雾法测定了在室内天维菌素对朱砂叶螨Tetranychus cinnabarinus、柑橘红蜘蛛Panonychus citri及二斑叶螨Tetranychus urticae的毒力,并研究了其制剂对螨类害虫的田间防治效果。结果表明,天维菌素对朱砂叶螨若螨和雌成螨均具有较高的毒力,其LC50分别为0.011、0.11 mg(a.i.)/L,杀螨活性优于弥拜霉素、阿维菌素,但杀卵活性较差。田间试验中2%天维菌素微乳剂具有良好的速效性且具有一定的持效期,在有效成分8~40 mg/kg剂量下,对朱砂叶螨和二斑叶螨药剂处理14 d的防治效果分别为83.22%~92.77%和85.49%~92.64%,有效控制期在14 d以上;在有效成分75 mg/kg剂量下,对柑橘红蜘蛛防治效果最好,处理1、3、7、14 d的防治效果分别达96.53%、97.72%、98.05%和91.42%。表明天维菌素具有作为杀螨剂的潜力。

Acaricidal bioactivity and field efficacy of the novel macrolide compound tenvermectin against the mites

To clarify the acaricidal activity of tenvermectin against spider mites, the toxicities of tenvermectin to Tetranychus cinnabarinus, Panonychus citri and Tetranychus urticae were investigated with leaf disc spray in the laboratory, and the control effects of tenvermectin on spider mites were studied in the field. The results showed that the toxicities of tenvermectin to the nymphs and female adults of T. cinnabarinus were higher than those of milbemycin and avermectin, and the LC₅₀ values were 0.011 and 0.11 mg (a.i.)/L, respectively, but the ovicidal activity was poor. The field experiments showed that tenvermectin provided a good rapid and residual efficacy period. The control efficacy of 2% tenvermectin microemulsion at the dosage of 8-40 mg/kg against T. cinnabarinus and T. urticae treated after 14 days were 83.22%-92.77%and 85.49%-92.64%, respectively. It showed good residual efficacy for up to 14 days. The control efficacy of 2% tenvermectin microemulsion at the dosage of 75 mg/kg on P. citri treated after 1, 3, 7, 14 days were 96.53%, 97.72%, 98.05% and 91.42%, respectively. The results indicated that tenvermectin could potentially control the spider mite populations.