环丙氟虫胺对小菜蛾的室内活性与田间防效

Bioactivity and field efficacy of cyproflanilide againstPlutella xylostella (L.)

[目的]测试并评价环丙氟虫胺对小菜蛾的室内活性及田间防效,为登记和应用推广提供科学依据。[方法]以溴虫氟苯双酰胺、氯虫苯甲酰胺、阿维菌素为对照,采用浸叶法测试环丙氟虫胺对敏感、上海、广东3个小菜蛾种群的室内活性;以溴虫氟苯双酰胺、乙基多杀菌素、溴氰虫酰胺为对照,在上海和广东开展了3年2地田间小区药效试验。[结果]室内生测结果表明:环丙氟虫胺对敏感、上海和广州3个不同种群小菜蛾LC50值为0.0488~0.0516 mg/L;上海种群对氯虫苯甲酰胺和阿维菌素的抗性倍数(RR值)分别为10.31、12.61,表现为中等水平抗性;广东种群对氯虫苯甲酰胺和阿维菌素的RR值分别为699.52、2671.90,表现为极高水平抗性。田间小区试验表明:以15~30 g a.i./hm^(2)在卵孵至低龄幼虫发生期施用,20%环丙氟虫胺SC对小菜蛾药后3、7、10 d的平均防效为87.75%~92.23%、91.55%~94.98%、90.03%~94.42%,与对照药剂溴虫氟苯双酰胺相当(15 g a.i./hm^(2)防效90.08%~92.15%),显著优于乙基多杀菌素(36 g a.i./hm^(2)防效79.44%~85.09%),略优于溴氰虫酰胺(18 g a.i./hm^(2)防效83.23%~90.03%)。20%环丙氟虫胺SC对甘蓝和小白菜安全。[结论]环丙氟虫胺对敏感种群及氯虫苯甲酰胺和阿维菌素抗性小菜蛾均具有高活性,与氯虫苯甲酰胺、阿维菌素之间没有交互抗性,有利于治理抗性害虫。20%环丙氟虫胺SC防治蔬菜小菜蛾的推荐用药量15~22.5 g a.i./hm^(2),对水量750 L/hm^(2),于小菜蛾卵孵至低龄幼虫发生期施药1次,防效可保持7~10 d。鉴于环丙氟虫胺是创制新农药,且作用机制新颖,进入市场后需要科学合理使用,不能在同一生长季节重复多次使用,建议与不同作用机制的药剂轮换使用。

[Aims]The bioactivity and field efficacy of cyproflanilide against Plutella xylostella were tested and evaluated,in order to support registration and application technology.[Methods]The bioactivity of cyproflanilide against P.xylostella(sensitive,Shanghai and Guangdong populations)was tested by leaf-dipping method with broflanilide,chlorantraniliprole and abamectin as control agents.Field plot efficacy trials were conducted with broflanilide,spinetoram and cyantraniliprole as control agents in Shanghai and Guangdong in 3 years for 2 plots per year.[Results]The Bioassay showed that the LC50 values of cyproflanilide to the three different populations of P.xylostella were 0.0488-0.0516 mg/L.The Shanghai population indicated moderate resistance to chloramphenicol and abamectin with resistance ratio(RR)of 10.31 and 12.61,respectively.The Guangdong population indicated high resistance to chloramphenicol and abamectin with RR of 699.52 and 2671.90,respectively.Applied from incubation of eggs to the onset of young larvae in field trials,the average control effect of cyproflanilide 20%SC was 87.75%-92.23%,91.55%-94.98%,and 90.03%-94.42%on day 3,7,and 10 after treatment at a dosage of 15-30 g a.i./ha,which was equivalent to that of broflanilide(90.08%-92.15%at 15 g a.i./ha),significantly better than that of spinetoram(79.44%-85.09%at 36 g a.i./ha),and slightly better than that of cyantraniliprole(83.23%-90.03%at 18 g a.i./ha).Cyproflanilide 20%SC was safe for cabbage and pakchoi.[Conclusions]Cyproflanilide shows high activity against sensitive populations of P.xylostella and populations that are resistant to chlorantraniliprole and abamectin.At the same time,cyproflanilide has no cross resistance with chloramphenicol and abamectin,which is beneficial for the management of resistant pests.The recommended application technique for the control of vegetable P.xylostella with cyproflanilide 20%SC is to use a dosage of 15-22.5 g a.i./ha with a water amount of 750 L/ha.The control effect can be maintained for 7-10 d when applied once from incubation of eggs to the onset of young larvae.Given that cyproflanilide is a newly developed insecticide with novel mechanisms of action,it should be used scientifically and reasonably after entering the market,and cannot be reused multiple times in the same growth season.It is recommended to use in rotation with insecticides with different mechanisms of action.