Bemisia tabaci, sweetpotato whitefly, has been recognized one of the most destructive insect pests worldwide because of increased resistance to some insecticide groups requiring alternative strategies for its control. We conducted a study of the influence of relative humidity, temperature and different developmental stages on the susceptibility of sweetpotato whitefly to conidia of Isaria javanica isolate, which had been reported high virulence against Q biotype of B. tabaci. The mortality of tobacco whitefly was low at low constant relative humidities, but was high when kept high humidity for first 24 hours and transferred to low humidity. The Isaria isolate had wide range of temperature (15℃ to 35℃) to control sweetpotato whitefly. The isolate has virulence to the egg and all developmental stages of nymph of B. tabaci. These results indicated that the isolate had good control effects at various environmental conditions and is an excellent candidate to develop a microbial pesticide to control sweetpotato whitefly.

• Hong Zhu(Agricultural Microbiology Division, National Academy of Agricultural Science, RDA, Key Laboratory of Microbial Control, Anhui Agricultural University)
• Jeong Jun Kim(Agricultural Microbiology Division, National Academy of Agricultural Science, RDA)
• Ji Hee Han(Agricultural Microbiology Division, National Academy of Agricultural Science, RDA)
• Sang Yeob Lee(Agricultural Microbiology Division, National Academy of Agricultural Science, RDA)