Compatibility of the entomopathogenic fungus Metarhizium anisopliae senso lato with imidacloprid for control of Microcerotermes diversus Silvestri (Iso.:Termitidae) in labratory conditions

Proliferation and virulence of entomopathogenic fungi can be affected by exposure to pesticides. Compatibility of Metarhizium anisopliae (Metschnikoff) Sorokin (DEMI 001 strain) with imidacloprid (IMI) was assayed by evaluating IMI effects on conidial germination، mycelial growth and sporulation. SDAY fungal cultivation medium was amended with IMI at concentrations of 10، 100 and 500 ppm. SDAY medium without insecticide was used as control treatment. The medium was inoculated by conidial suspension and the number of germinated conidia was counted after 24 h. Mycelial growth and sporulation were also measured. Results showed that IMI had no negative effect on conidial germination or mycelial growth. However، sporulation was progressively reduced as IMI concentrations increased. At the highest concentration of IMI، sporulation was reduced to 2. 40×107 conidia ml-1، compared with control at 4. 93×107 conidia ml-1. According to these results، IMI is reasonably compatible with strain DEMI 001. Additionally، mortality of M. diversus caused by either M. anisopliae or IMI alone، and in combination with different sublethal concentrations of IMI، was evaluated in laboratory bioassays. Mortality in combined treatments was significantly higher compared with non-combination treatments، indicating possible synergistic effects.