Su T, Mulla M S
Department of Entomology, University of California, Riverside 92521-0314, USA.
J Vector Ecol. 1998 Dec;23(2):114-22.
In order to develop and utilize new botanical insecticides originating from neem (Azadirachta indica A. Juss) in mosquito control programs as a potential larvicide, the antifeedant activity of three formulations of neem against the larvae of Culex tarsalis Coquillett and Culex quinquefasciatus Say was investigated under laboratory conditions. A significant antifeedancy was indicated at 5 ppm and 10 ppm azadirachtin (AZ) for all formulations and both species. Within the test concentration range of AZ (1-10 ppm), 5 ppm was the minimum effective concentration for antifeedancy in most cases. Some differences in larval susceptibility in terms of antifeedancy to the test formulations were noted between the two species. The Cx. tarsalis larvae were more susceptible than Cx. quinquefasciatus larvae to Azad EC 4.5 at 1 ppm during the first 15-min exposure period and at 5 and 10 ppm during the whole test period. The Cx. quinquefasciatus larvae were more susceptible than Cx. tarsalis larvae to Azatin WP 4.5 at 1, 5, and 10 ppm during the first 15-min exposure period or to Neemix EC 4.5 at 1 ppm during the first 45-min exposure period. The formulation-related differences in antifeedant activity appeared when the concentration increased from 1 to 10 ppm. In Cx. tarsalis, the Azad EC 4.5 and Neemix EC 4.5 were more effective than Azatin WP 4.5 at 5 ppm during the first 15-min exposure period and at 10 ppm during the whole test period. In Cx. quinquefasciatus, the Azatin WP 4.5 and Neemix EC 4.5 were more effective than Azad EC 4.5 at 1 ppm during the first 30-min exposure period, and at 5 ppm during the first 60-min exposure period, and at 10 ppm during the whole test period.
为了开发和利用源自印楝（印楝Azadirachta indica A. Juss）的新型植物源杀虫剂，将其作为潜在的杀幼虫剂用于蚊虫控制项目，在实验室条件下研究了三种印楝制剂对致倦库蚊（Culex tarsalis Coquillett）和致乏库蚊（Culex quinquefasciatus Say）幼虫的拒食活性。所有制剂以及两种库蚊在印楝素（AZ）浓度为5 ppm和10 ppm时均表现出显著的拒食作用。在AZ的测试浓度范围（1 - 10 ppm）内，5 ppm在大多数情况下是拒食的最低有效浓度。两种库蚊在对测试制剂的拒食敏感性方面存在一些差异。致倦库蚊幼虫在最初15分钟暴露期对1 ppm的Azad EC 4.5以及在整个测试期对5 ppm和10 ppm的Azad EC 4.5比致乏库蚊幼虫更敏感。致乏库蚊幼虫在最初15分钟暴露期对1 ppm、5 ppm和10 ppm的Azatin WP 4.5，或在最初45分钟暴露期对1 ppm的Neemix EC 4.5比致倦库蚊幼虫更敏感。当浓度从1 ppm增加到10 ppm时，出现了与制剂相关的拒食活性差异。在致倦库蚊中，Azad EC 4.5和Neemix EC 4.5在最初15分钟暴露期对5 ppm以及在整个测试期对10 ppm比Azatin WP 4.5更有效。在致乏库蚊中，Azatin WP 4.5和Neemix EC 4.5在最初30分钟暴露期对1 ppm、在最初60分钟暴露期对5 ppm以及在整个测试期对10 ppm比Azad EC 4.5更有效。
