Entomopathogenic nematode (EPN), Heterorhabditis indica proved effective against mango stem borer, Batocera rufomaculata De Geer

Abstract

India during 2020-23 to evaluate the efficacy of native strains of two species of entomopathogenic nematodes (EPN), viz., Heterorhabditis indica and Steinernema carpocapsae against larvae of mango stem borer, Batocera rufomaculata De Geer (Coleoptera: Cerambycidae). Bioassay studies revealed the virulence of all five strains tested and based on the LC value (10.72), H. indica (IIHR-2) was selected to be the most effective one and further evaluated under in vivo and field conditions. Similar efficacy levels were recorded when it was tested against larvae reared on drumstick twigs to simulate natural habitat of stem borer larvae. Finally, IIHR-2 strain of H. indica was evaluated under field conditions by injecting the EPN suspension into the trunks of mango trees infested with stem borer. An insecticide treatment was maintained as a standard check. The EPN has resulted in 81.72% reduction in stem borer damage by larvae of B. rufomaculata compared to 90.80% with insecticide. Though it was marginally lower that chemical treatment, considering the merits of non-chemical treatments to the environment and sustainable crop management, EPN can be recommended as an effective component of stem borer management. This is the first insight into establishing the efficacy of EPN against mango stem borer, B. rufomaculata under laboratory and field conditions.