4种植物源杀虫剂对亚洲型舞毒蛾幼虫的毒性与拒食作用

Comparison of the toxicities and antifeedant effects of four botanical insecticides against the larvae of Lymantria dispar asiatica Vnukovskij

为筛选出有效防治亚洲型舞毒蛾的最佳植物源杀虫剂,采用5%鱼藤酮、1%虫菊.苦参碱、5%桉油精、0.6%氧苦.内酯4种植物源杀虫剂,比较它们对舞毒蛾3龄幼虫胃毒和触杀处理后的毒性与拒食作用。结果表明:这4种植物源杀虫剂对舞毒蛾3龄幼虫均具有胃毒和触杀两种作用,其急性毒性总体表现为触杀处理大于胃毒处理,而在各自相对最高的浓度条件下,以0.6%氧苦.内酯的胃毒急性毒性为最大、5%桉油精次之;由于胃毒组的LC50均小于触杀组,因而胃毒处理的毒力更高;此外,0.6%氧苦.内酯和5%桉油精的胃毒和触杀毒力均远远高于其他两种药剂,并以前者为最高。对测定前后的饲料量进行比较后发现,4种药剂对舞毒蛾3龄幼虫均具有很好的拒食作用,尤其以5%桉油精5 000倍液处理的拒食率高达99.31%。因此,0.6%氧苦.内酯和5%桉油精可作为防治亚洲型舞毒蛾的首选植物源杀虫剂推广应用。

In order to choose the best botanical insecticide for controlling Asian gypsy moth, Lymantria dispar asiatica, we compared toxicities and antifeedant effects of four botanical insecticides on the 3rd instar larvae, including 5% Rote- none, 1% resmethrin-matrine, 5% eucalyptole and 0. 6% Oxymatrine-lactone. The results indicated that the four kinds of botanical insecticides all had the functions of stomach poison and contact toxicity, and the acute toxicity performance showed that the function of contact toxicity was more obvious than stomach poison. When botanical insecticides were di- luted at the highest concentration, the stomach poison of 0. 6 % Oxymatrine-lactone had the most mortality, followed by 5 % eucalyptole. Due to the LC50 of stomach poison groups were all less than that of contact toxicity groups, the stomach poison had a more toxic. Moreover,the toxicities of 0. 6 % Oxymatrine-lactone and 5 % eucalyptole were much higher than the other two botanical insecticides, and the toxicities of 0. 6 % Oxymatrine-lactone was the strongest. Comparing the weight of feedingstuff before and after feeding,we found that the antifeedant effects of Asian gypsy moth 3rd instar larvae performed well under the four kinds of botanical insecticides treatments, and the antifeedant rate under 5 % euca- lyptole diluted 5 000 times reached to 99.31%. It was deduced that 5 % eucalyptole and 0. 6 % Oxymatrine-lactone could be popularized and applied as botanical insecticides to control Asian gypsy moth.