Development Of A Fungal Insecticide Formulation For Control Of The Lesser Tea Leafhopper, Empoasca Vitis

The lesser tea leafhopper, Empoasca vitis (Homoptera: Cicadellidae) is the mostserious tea tree pest, which has developed high resistance to almost all insecticides andneeds biological alternatives. In the present study, an isolate of Isaria javanicus from thelesser tea leafhopper, Empoasca vitis and4isolates of Beauveria bassiana from otherleafhoppers were tested for their extracellular protease. I. javanicus isolate and2Beauveriaisolates were screened out for bioassay to early instar nymphs of the leafhopper. The resultindicate that the virulence of I. javanicus isolate was2.33~7.26times and6.08~27.26times higher than that of two Beauveria isolates, with a LT50of5.9d at the concentrationof1×108conidia.mL-1, which caused100%mortality on the13thd. IJOD-1, an oildispersion formulation IJOD-1, was developed from the Isaria isolate for field trail. Fieldtrail with randomized block design demonstrated that IJOD-1sprayed at a dose of7.5×1013conidia ha-1resulted in population decrease of50.32%on the11thd. A supplementaryspray was carried out on the25thd and caused a total population decrease of68.4%on the55thd. The storage results of IJOD-1showed that spore’s germination rate declined slowlyboth at room temperature and at4℃within the1styear of storage, while the lowertemperature benefited the storage. Germination rate of spores of stored at4℃remained57%and40.33%on the12thand the15thmonth storage, respectively.Compered with thoserefrigerated at4℃, spores at room temperature remained a germination rate of71.33%in8months storage. The decrease of germination accelerated in10months, and declined to42.67%and10.67%on the12thand15thmonth, respectively. However, sorage of purespores at room temperature decreased germination rate to61%in3months, thengermination rate declined sharply and droped to6.33%in6months, and finally nogermination was found in8thmonth storage at room temperature.