Abstract: 【Aim】In order to explain the different pathogenicity of Lecanicillium lecanii to adults, pupae and larvae of Boettcherisca peregrina, the adhesion capacity of L. lecanii conidia on body surface of B. peregrina at the three developmental stages and its relationship with the surface structures of insect body were analyzed. 【Methods】The number of conidia adhered to the surface of adults, pupae and larvae of B. peregrina were measured by hemocytometer, and the distribution of outgrowths and conidia on the body surface were observed by scanning electron microscope (SEM) and other microscopies.【Results】 There was significant difference in the adhesion number of L. lecanii conidia on the surface of three developmental stages of B. peregrina (P=0.0001). The adhesion number of L. lecanii conidia was (1.35±0.12)×10⁶, (0.57±0.09)×10⁶ and (0.45±0.06)×10⁶ on each adult, pupa and larva, respectively. Many L. lecanii conidia adhered to microchaetae of adults. Only few L. lecanii conidia were found to adhere to "rope" folds on the bottom of the thorns in pupae. No adhered L. lecanii conidia on larvae were found. 【Conclusion】 The adhesion capacity of L. lecanii conidia is closely associated with the body surface structures of adults, pupae and larvae of B. peregrina, resulting in the different pathogenicity of L. lecanii  to these different developmental stages of B. peregrina.

Key words: Boettcherisca peregrina, Lecanicillium lecanii, conidia, surface structure, scanning electron microscope