Potential of some Irianian isolates of Akanthomyces for microbial control of cotton mealybug, Phenacoccus solenopsis, under greenhouse conditions

The cotton mealybug, Phenacoccus solenopsis Tinsely (Hemiptera: Pseudococcidae), is an important pest of many plants in agroecosystems and urban green landscapes. In this study, potential of three isolates of Akanthomyces lecanii, isolates PAL6, PAL7, and PAL8, and an isolate of A. muscarius, isolate GAM5, to microbial biocontrol of this pest on Coleus blumei, as the pest host plant, were investigated under greenhouse conditions. The infested host plants to five last instar nymphs were treated using different conidial suspension concentrations (104,105, 106, 107, and 108 conidia/mL) of each isolate and the mealybug mortalities were recorded every day, for eight days. The mortalities were varied from 14.3% (isolate PAL7) to 1.79% (isolate PAL8). The highest mortality was observed in concentration of 108 conidia/mL of the pathogens. The highest mortality caused by the pathogens was recorded six days after treatment. Totally, conidial suspension concentration of 108 conidia/mL from A. lecanii PAL7 was the best candidate for microbial biocontrol of the mealybug among the pathogens causing 56.17% mortality in the pest population six days after treatment. The results can be used for developing microbial biocontrol of the cotton mealybug especially in greenhouse conditions.