Field evaluation of the entomopathogenic nematodes against the white grub, Leucopholis lepidophora Blanchard (Coleoptera: Scarabaeidae)

Abstract

The ability of entomopathogenic nematodes to suppress larval populations of the white grub, Leucopholis lepidophora Blanchard (Coleoptera: Scarabaeidae), infesting the areca nut palm (Areca catechu) was investigated under field conditions over a 2-year period (2015–2017). Heterorhabditis indica at two application rates (1.7 × 105 and 3.5 × 105 IJs palm−1) caused higher percentage reduction of L. lepidophora larvae than Steinernema abbasi and chlorpyrifos. Chlorpyrifos-treated plots caused higher percentage of reduction of the grub larvae than S. abbasi at the lowest rate (1.7 × 105 IJs palm−1). However, S. abbasi at 3.5 × 105 IJs palm−1 performed at least equally well than the chlorpyrifos treatment. The kernel yield from H. indica-treated plots at 3.5 × 105 IJ palm− 1 was 85.4% higher than those from water control and 33.3% higher than that in the chlorpyrifos treatment. The kernel yields varied significantly among different treatments. The cost-benefit analysis showed that H. indica is a promising biocontrol agent for the management L. lepidophora control in areca nut field.