INFECTION BEHAVIOR OF ENTOMOPATHOGENIC FUNGUS ASCHERSONIA ALEYRODIS ON BEMISIA TABACI
昆虫病原真菌粉虱座壳孢对烟粉虱侵染行为的初步研究

Aschersonia aleyrodis is an important insect pathogen, which can be used as biocontrol agent against worldwide sweetpotato whitefly, Bemisia tabaci. Investigation of infection characteristic of the fungus revealed that first to third instar nymphs were most susceptible and the infection rate of second instar nymphs could reach 98%. Infection rate increased with prolongation of treatment duration or increase in concentration of conidia. Infected whitefly nymphs usually died in the following stage after treatments. Scanning electron microscopy and light microscopy were employed to investigate the infection process of A. aleyrodis on the pest. The germ tube of conidia might penetrate directly into the cuticle or by means of an appressorium, with preference of intersegmental membranes as the site of infection,and mycelial production then followed. Mycelia protruded from margins of cadavers and the conidia could infect other new members if humidity was high enough.