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

Jagadeesh Patil,Vijayakumar Rangasamy

doi:10.1186/s41938-018-0046-z

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.

Highlights

Root injury caused by the larvae of the white grub, Leucopholis lepidophora Blanchard (Coleoptera: Scarabaeidae), threatens the production of areca nut palm or betel nut palm L. (Areca catechu) in the Western Ghats, Eastern Ghats and East and North Eastern regions of India
Previous studies have shown that Entomopathogenic nematodes (EPNs) species such as Steinernema scarabaei Stock and Koppenhofer, S. longicaudum Shen and Wang, S. lanmjungense Khatri-Chhetri, Heterorhabditis bacteriophora Poinar, H. zealandica Poinar and H. indica Poinar (Koppenhofer et al 2000; Koppenhofer and Fuzy 2003; Grewal et al 2004; Du et al 2009; Khatri-Chhetri et al 2011; Guo et al 2015 and Patil et al 2015) were highly virulent to larvae of many species of white grubs
The present study aimed to evaluate the efficacy of two EPN species, Steinernema abbasi Elawad and H. indica Poinar along with the commonly used chemical insecticide in an areca nut field infested with L. lepidophora

Summary

Background

Root injury caused by the larvae of the white grub, Leucopholis lepidophora Blanchard (Coleoptera: Scarabaeidae), threatens the production of areca nut palm or betel nut palm L. (Areca catechu) in the Western Ghats, Eastern Ghats and East and North Eastern regions of India. L. lepidophora is a basically dominant white grub species in high rainfall and Western Ghats regions of India and is widely regarded as the most serious threat to areca nut production in India (Veeresh 1983), causing yield losses up to 39.8–41. Previous studies have shown that EPN species such as Steinernema scarabaei Stock and Koppenhofer, S. longicaudum Shen and Wang, S. lanmjungense Khatri-Chhetri, Heterorhabditis bacteriophora Poinar, H. zealandica Poinar and H. indica Poinar (Koppenhofer et al 2000; Koppenhofer and Fuzy 2003; Grewal et al 2004; Du et al 2009; Khatri-Chhetri et al 2011; Guo et al 2015 and Patil et al 2015) were highly virulent to larvae of many species of white grubs. The present study aimed to evaluate the efficacy of two EPN species, Steinernema abbasi Elawad and H. indica Poinar along with the commonly used chemical insecticide (chlorpyrifos) in an areca nut field infested with L. lepidophora

Methods

Results and discussion

Conclusions