Pathogenicity of entomopathogenic fungi Beauveria bassiana and Metarhizium (Nomuraea) rileyi against castor hairy caterpillar, Euproctis fraterna (Lepidoptera: Lymantriidae)

Abstract

The castor hairy caterpillar, Euproctis fraterna is the most destructive insect pest of castor, damaging the crop during both kharif and rabi seasons. Biocontrol agents, particularly entomopathogens are potential alternatives to chemical pesticides for safe and eco-friendly insect pest management. Pathogenicity of the entomopathogenic fungi viz., Beauveria bassiana and Metarhizium (Nomuraea) rileyi were evaluated against larvae of the E. fraterna under laboratory conditions. Among the entomopathogenic fungi, B. bassiana recorded high pathogenicity against E. fraterna (80 ± 5.8% larval mortality), while moderate pathogenicity was observed with M. rileyi (60 ± 5.8% larval mortality) treated at the concentration of 108 conidia/ml. B. bassiana recorded the least median lethal concentration (LC50) for E. fraterna (4.4 × 105 conidia/ml) as compared to M. rileyi (LC50 at 5.8 x 106conidia/ml). B. bassiana also recorded the shortest median lethal time (LT50 value of 3.9 days) to cause the larval mortality in E. fraterna¸ while M. rileyi recorded LT50 value of 4.5 days. The entomopathogenic fungi, B. bassiana can be used in IPM programme as a potential bio-control agent against E. fraterna in castor.