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本试验从５０余种抗生素中筛选出了对棉铃虫有效的杀虫抗生素——Ａｖｅｒｍｅｃｔｉｎ，并研究了其对棉田的七星瓢虫、草间小黑蛛和螟黄赤眼蜂蛹等主要天敌的影响。结果表明，用Ａｖｅｒｍｅｃｔｉｎ各组份中毒力最强的Ｂ１组份４０ｍｇ／Ｌ浓度处理柞蚕卵内的螟黄赤眼蜂，其校正死亡率仅为１１％，说明Ａｖｅｒｍｅｃｔｉｎ作为生物杀虫剂，对赤眼蜂较安全；对七星瓢虫的结果显示，其校正死亡率为４３．２８％，说明影响不大。而Ａｖｅｒｍｅｃｔｉｎ各组份对蜘蛛类的毒性很强，Ｂ１组份的１０ｍｇ／Ｌ浓度处理草间小黑蛛，其校正死亡率１００％，比对瓢虫的ＬＣ５０强３倍以上。根据近几年棉田天敌种群的分析，捕食性天敌以瓢虫为主，赤眼蜂也是对棉铃虫寄生效果较好的天敌，因此，Ａｖｅｒｍｅｃｔｉｎ在棉田中使用，有利于保持田间优势天敌种群
In this study, avermectin, an effective insecticide antibiotic against cotton bollworm, was screened from more than 50 kinds of antibiotics. The effects of avermectin on the main natural enemies of cotton budworm, Coccinella septempunctata, influences. The results showed that the corrected mortality of Trichogramma ostriniae in the tussah eggs treated with 40 mg / L of B1, the most virulent component of Avermectin, was only 11%, indicating that Avermectin was a biocide against red Eye bee is safe; the results of the ladybird ladybird, its corrected mortality rate was 43.28%, indicating little effect. The Avermectin components of arachnoid toxicity is very strong, B1 component 10mg / L concentration treatment of the grass black spider, the corrected mortality of 100%, more than three times higher than the LC50 ladybug. According to the analysis of natural enemies in cotton fields in recent years, predatory natural enemies are ladybugs and Trichogramma repellent is also a natural enemy to the parasitism of cotton bollworm. Therefore, Avermectin is used in cotton fields,