COMPARATIVE EFFECTIVENESS OF ENTOMOPATHOGENIC FUNGI AGAINST OKRA MEALYBUG PHENACOCCUS SOLENOPSIS

Microbial formulations prepared from entomopathogenic fungi emerging as the effective alternate of chemical pesticides against different crop pests. They cause lethal infections and regulate insects and mites population in nature by epizootics and considered as primary candidates for mycoinsecticides. In this study, we evaluated five species of entomopathogenic fungi such as Beauveria bassiana, Metarhizium anisopliae, Isaria farinosa, Paecilomyces lilacinus and Verticillium lecanii against Phenacoccus solenopsis on okra crop. Three concentrations calculated on the basis of previous study (LD50, ten times higher and ten times lower than LD50) of each fungal biocontrol agent were applied to okra plants infested with mealybugs. In the pot experiment, the higher dose of M. anisopliae (7.063?108) and B. bassiana (1.37?108) followed by P. lilacinus (6.615?107) were highly effective in controlling the pest population, they brought 83.7, 80 and 78.7% reduction, respectively. Second most effective treatments were a higher dose of V. lecanii (1.69?107) and a medium dose of P. lilacinus (6.615?106), brought 69.4 and 53% reduction in mealybugs. Among all entomopathogenic fungi, I. farinosa was the least effective; its lower, medium and higher doses caused only 20.7, 48.5 and 51.6% reduction, respectively. In field trial, higher doses of all biocontrol agents were more effective than their medium and lower doses. Whereas, maximum yield was recorded in the higher (7.063?108) and medium dose of (7.063?107) of M. anisopliae followed by a higher (1.37?108) and medium (1.37?107) dose of B. bassiana. This study provides new opportunities for effective and eco-friendly control measures of mealybugs.

Automated summary

Microbial formulations from entomopathogenic fungi are emerging as effective alternatives to chemical pesticides in controlling crop pests. Among the five species tested in this study, higher doses of Metarhizium anisopliae, Beauveria bassiana, and Paecilomyces lilacinus were most effective in reducing the population of mealybugs on okra plants. Additionally, field trials showed higher doses of all biocontrol agents were more effective in controlling mealybug populations and increasing crop yield.