Abstract: Strains ZJLA08, ZJLP09 and ZJLSP07, Lecanicillium species isolated from Diaphorina citri cadavers, were identified as Lecanicillium attenuatum, Lecanicillium psalliotae and a new species of Lecanicillium, and showed strong pathogenicity against D. citri. In order to make clear the biological characteristics of these strains, effect of temperature, light and UV irradiation on mycelial growth, sporulation quantity and conidial germination were determined. The results showed that the optimum temperature for mycelial growth, sporulation quantity and conidial germination of these three strains was 25 ℃ to 30 ℃. Light did not exert significant effect on mycelial growth and conidial germination, while was beneficial to sporulation.The sporulation quantity of strains ZJLSP07, ZJLA08 and ZJLP09 were 6.72×10⁸, 6.13×10⁸ and 10.38×10⁸ conidia·mL^-1 after 7 days of incubation under continuous light. UV irradiation exhibited a dose-dependent inhibition effect on mycelial growth, sporulation quantity and conidial germination. After exposure to UV light for 60 min, the inhibition rates to sporulation quantity of strains ZJLSP07, ZJLA08 and ZJLP09 were 38.32%, 51.17% and 32.41%, and to conidial germination were 81.43%, 87.35% and 78.14%, respectively. High humidity could facilitate conidial germination. At 62% relative humidity, the conidial germination rates of strains ZJLSP07, ZJLA08 and ZJLP09 dropped by 84.31%, 86.21% and 77.47%, compared to those at 100% relative humidity. The mycelial growth rate, sporulation quantity and conidial germination rate of strain ZJLP09 were higher than the other two under the same conditions, and had stronger tolerance to high temperature, low humidity and UV irradiation.

Key words: Asian citrus psyllid, Lecanicillium, UV irradiation, conidial germination