七星瓢虫对茶蚜的捕食功能反应及生物农药的安全性评价

Predation Functional Responses of Coccinella septempunctata Linnaeus to Toxoptera aurantii( Boyer) and Security Evaluation of Several Botanical Biopesticides

研究不同虫态的七星瓢虫对茶蚜的捕食作用以及4种植物性生物农药对七星瓢虫成虫的毒力与安全性评价。结果表明：不同虫态的七星瓢虫对茶蚜的捕食功能反应符合 Holling－Ⅱ功能反应模型；七星瓢虫1～4龄幼虫和雌成虫捕食茶蚜的理论日最大捕食量分别为24．8，83．3，212．8，434．8，384．6头。随着七星瓢虫幼虫龄期的增加，其对茶蚜的捕食量急骤上升，但瓢虫4龄幼虫对茶蚜的捕食量大于雌成虫。4种植物性生物农药对七星瓢虫成虫的LC50值差异显著。 LC50值由大到小依次为1．8％除虫菊素水乳剂、0．6％氧苦·内酯水剂、0．2％苦皮藤素水剂、0．3％苦参碱水剂，但是，在田间推荐使用剂量下，4种植物性生物农药对七星瓢虫的安全系数由大到小依次为0．6％氧苦·内酯水剂、0．2％苦皮藤素水剂、0．3％苦参碱水剂、1．8％除虫菊素水乳剂。

The predatory function of Coccinella septempunctata Linnaeus to Toxoptera aurantii （ Boyer） of different ages was investigated,and the virulence and security of four botanical to C.septempunctata were evaluated.The results showed that the functional responses of C.septempunctata larvae in different instars and adult females predating on the aphids,T.aurantii fitted the model of Holling II type.The maximum predation rates of first-fourth instar larvae and adult female of C.septempunctata were 24.8,83.3,212.8,434.8 and 384.6 preyday,respectively. The predation rates of C. septempunctata on T. aurantii increased sharply as the instar progressed.The fourth instar larvae preyed more T.aurantii than the adult female.The differences in the median lethal concentrations of the four botanical biopesticides for the adults of C.septempunctata was significant.The sequence of the median lethal concentrations from large to small was 1.8%pyrethrin EW,0.6%oxymatrine prosuler agent,0.2% celangulin agent and 0.3% matrine agent.However,under the condition of the field recommended doses,the sequence of the safety factors of the four botanical biopesticides for C. septempunctata from large to small was 0.6% oxymatrine prosuler agent,0.2% celangulin agent,0.3% matrine agent and 1.8%pyrethrin EW.