Hirsutella citriformis Speare is an important entomopathogenic fungus that infects diverse species of hemipteran insects, including the vector of huanglongbing, Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). The objective of this study was to determine the growth and conidiation of eight isolates of H. citriformis as well as virulence of the conidia on Asian citrus psyllid adults and nymphs. The strains were isolated from infected D. citri in states of Mexico where citrus, Citrus spp., are grown. Optimum radial growth was obtained at 25°C for the eight isolates incubated in three agar media (potatodextrose agar, potato dextrose agar with 0.5% yeast extract, and Sabouraud dextrose agar). Most daily radial growth was by six strains and most production of conidia (1.833 × 10⁷ per milliliter) was by strain IB-Hir-2 after 34 days of incubation on potato dextrose agar with 0.5% yeast extract. In a preliminary bioassay, strains INIFAP-Hir-1, IB-Hir-2, and IB-Hir-1 killed most (88.1, 87.7, and 85.6%, respectively) Asian citrus psyllid adults inoculated by contact. From 50.5–81.7% of the nymphs died.