Exploring Efficacious Microbial Bio-agents and Insecticides Against White Grubs in Sugarcane in Indo-Gangetic Plains

Abstract

White grubs are polyphagous subterranean insect pests which have recently emerged as a major threat to sugarcane cultivation. For effective management of these pests in sugarcane, studies were undertaken to evaluate various locally isolated as well as commercially available microbial biocontrol agents, entomopathogenic nematodes and novel chemical pesticides against white grubs. Attempts were made to isolate effective bio-agents associated with white grubs in indo-gangetic plains of India. Altogether, nine local bacterial isolates associated with infected white grubs were isolated and tested for their bio-efficacy under laboratory condition. However, none of the isolates were found effective against the predominant species, Holotrichia consanguinea. Hence, attempt was made to assess the field efficacy of already available five microbial bio-agents, viz., Metarhizium anisopliae, Beauveria bassiana, Bacillus cereus strain WGPSB-2, Heterorhabditis indica, Steinernema carpocapsae and three insecticides, viz., Chlorantraniliprole 0.4 G, Fipronil + Imidacloprid 80 G and Chlorpyriphos 10 G at their recommended doses. Results of the experiments conducted for 2 years under randomized block design revealed that treatment of Bacillus cereus strain WGPSB-2 @10 kg/ha (1 × 1013 cfu/ha) could reduce the white grub damage to the extent of 59.8%, while other bio-agents could reduce the damage in the range of 24.3–39.5% over untreated control. All the insecticides were found effective in reducing white grub damage, and in most of the observations, difference in reduction in the white grub damage was statistically non-significant. However, Chlorantraniliprole 0.4 G @ 20 kg/ha was most effective, which could reduce the grub damage to the extent of 89.10% over untreated control.