Abstract: To explore the application of Lecanicillium lecanii in combination with biological pesticides against the Aphis glycines, we cultured the conidia of L. lecanii BNCC336750 with PDA media and measured their toxicity to A. glycines by using leaf dipping method in laboratory. A spore suspension of higher toxicity obtained through bioassway as mixed with sub-lethal concentrations of three pesticides. The results indicated that the mortality of A. glycines increased with the increase of conidia liquid concentration of L. lecanii, the highest toxicity was reached at 108 spores/mL. The laboratory results showed a synergistic effect on the control efficacy of the mixture over that obtained with spore solution or sub-lethal pesticides solutions alone. Among the pesticides, nimbin mixed L. lecanii had the highest control, with cumulative corrected mortality of 94.16% at the 7th day. The cumulative corrected mortalities of matrine and imidachloprid mixed with L. Lecanii were 86.13% and 80.29% at the 7th day, respectively. Field experiments showed a highest control of 89.47% with the mixtures of L. lecanii and nimbin at the 7th day. Therefore, low concentration insecticides mixed with L. lecanii had good control against A. glycines, thus reducing the amount of pesticides substantially.

Key words: Lecanicillium lecanii, biological control, control effect, Aphis glycines