Biocontrol potential of Entomopathogenic nematode ( <i>Heterorhabditis indica)</i> against the grubs of Hadda beetle <i>Henosepilachna vigintioctopunctata</i> (Coleoptera: Coccinellidae) on Ashwagandha ( <i>Withania somnifera</i> ) under laboratory c

ABSTRACT The Hadda beetle, also known as Henosepilachna vigintiactopunctata , was a significant pest of Ashwagnada, a medicinal plant grown extensively in the subtropical area, particularly in India. In the laboratory experiment, the entomopathogenic nematodes (EPNs) Heterorhabditis indica were evaluated for their infectivity and mortality effects on the grubs of hadda beetle at various concentrations viz., 1, 10, 25, 50, 75, and 100 infective juveniles (IJs) per 20 grubs against four distinct periods (24, 48, 72, and 96 h) maintained at a temperature of 30°C. The study demonstrated that the highest mortality rates were achieved at a concentration of 100 infective juveniles (IJs) per 20 grubs after 96 h. Despite the initial applications showing relatively low mortality percentages, the most effective larval control occurred after the 96 hrs of the exposure period. There was a positive correlation between the concentrations of infective juveniles and the exposure period for larval mortality. Application of H. indica at the rate of 231.66 IJs/grub can cause up to 90 percent mortality in the grub population under field conditions. The findings of these studies highlight the promising potential of H. indca as an eco‐friendly and sustainable method for controlling hadda beetle grubs in ashwaganda cultivation.