The lesser tea leafhopper,Empoasca vitis（Homoptera： Cicadellidae） is the most serious tea tree pest,which has developed high resistance to almost all insecticides and needs biological alternatives.In the present study,an isolate of Isaria javanicus from Empoasca spp.and 4 isolates of Beauveria bassiana from other leafhoppers were tested for their extracellular protease activity.I.javanicus isolate and two Beauveria isolates were screened out for further bioassay to early instar nymphs of the leafhopper.The result showed that the virulence of I.javanicus isolate was 2.33～7.26 fold and 6.08～27.26 fold higher,respectively,than that of the two Beauveria isolates,with LT50at 5.9 d under the concentration of 1×108conidia mL 1,which caused 100% mortality on the 13rd d.IJOD-1,an oil dispersion formulation was developed with the Isaria isolate for field test.The field test with a randomized block design demonstrated that IJOD-1 sprayed at a dose of 7.5×1013 conidia ha 1resulted in an efficacy of 50.32% on the 11thd;the second spray on the 25thd caused the efficacy of 68.40% on the 55thd.%茶小绿叶蝉Empoasca spp.是我国最重要的茶树害虫,几乎对所有化学农药都产生了很高的抗药性,亟需开发经济有效的生物农药。本研究通过对从茶小绿叶蝉上分离的1株爪哇棒束孢Isaria javanicus和4株自其它叶蝉上分离的球孢白僵菌Beauveria bassiana的胞外蛋白酶活性测定,初选出活性较高的爪哇棒束孢和两株球孢白僵菌;对假眼小绿叶蝉低龄若虫的生物测定结果显示,爪哇棒束孢毒力最强,分别比两株球孢白僵菌高2.33～7.26倍和6.08～27.26倍,在1×108孢子mL 1浓度条件下第13 d的致死率达100%,LT50为5.9 d。通过随机区组设计进行的田间防治试验结果表明,使用爪哇棒束孢菌株配制的IJOD-1悬乳剂以7.5×1013孢子hm 2的剂量常量喷施,对假眼小绿叶蝉虫口的防治效果在第11 d时为50.32%;第25 d时追加1次放菌,在第55 d时的防治效果达68.40%。
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