Abstract: ObjectiveThe adhesion capacities of Lecanicillium lecanii conidia on adults , larvae and pupae of Mus-ca domestica and the relationship with their surface structures were analyzed to provide references for explaining differ-ent pathogenicities of entomogenous fungi to different development stages of a certain insect. MethodTwo different ino-culation methods (dipping and spraying) were used and the number of conidia adhered to the surface of adults, pupae and larvae was measured by hemocytometer, respectively. Furthermore, the distribution of outgrowths and conidia on the body surface were observed by scanning electron microscope and other microscopies. ResultThe adhesion number of L. lecanii conidia on the surface of three development stages of M. domestica was very different (P<0.05) and the sequence was adults>pupae>larvae. Many outgrowths distributed on all parts of the adult body, such as setae, bristles and microtriches. Many L. lecanii conidia adhered to microtriches and the conidia secreted mucus to further strengthen the adhesion effect. The pupa body was covered with many “band” uneven folds, and there were sparse thorn bands on the junction of somites. There were no L. lecanii conidia adhered to the pupa body. Almost the whole larva body surface had no folds and there were merely thorn bands near the junction of somites. No L. lecanii conidia adhered to the larva body. ConclusionThe body surface structures of adults, pupae and larvae of M. domestica are closely associated with adhesion capacity of L. lecanii conidia.