Infection of Aedes albopictus by Tolypocladium cylindrosporum.

The infection process of Tolypocladium cylindrosporum in Aedes albopictus is discussed. The integument is a common site of infection. Spores of T. cylindrosporum are able to adhere to the exoskeleton and penetrate it. During its early stages of development the fungus is always surrounded by a thick bacterial muff. However these bacteria did not invade the host, and no bacterial cell was observed on the intact cuticle. Conidia filtered by larvae rapidly filled the gut and most of them were hydrolyzed in the midgut. Even if germination occurred at a low level in the digestive tract, the peritrophic membrane and the mesenteral cells were not penetrated by fungus.