By Umashankar Mishra
New Delhi: Over the years, sugarcane farmers have been fighting a losing battle against white grub infestation. Now Indian researchers have developed a new technique to deal with the problem.
Scientists at the Indian Agricultural Research Institute (IARI) have used a biological mixture of cadavers of an insect called Galleria malonella infected with a set of parasites called entomopathogenic nematode (EPN) to kill white grub.
Generally, synthetic pesticides such as organophosphate and carbamate are used to deal with this problem. But, the pest was developing resistance to them. A search was conducted for an alternative strategy. Studies across the world have shown that the EPNs are parasites of white grub and could be considered as an agent to control them.
While white grub is a parasite dependent on sugarcane, EPN is its parasite. Two major species of EPN – heterorhabditis and Steinernema, have generated much interest as potential bio-control agents as they carry lethal symbiotic bacteria in their guts, which is toxic to white grub. As part of their study, the researchers multiplied EPN in vivo, on a small scale, on the larvae of a pest called Greater Wax Moth (Galleria melonella). Galleria is the conventional host for in vivo multiplication of EPNs due to its several attributes, not the least of which is the ease with which it can be reared in plastic boxes or wooden trays on a diet of wheat/corn flour, wheat/rice bran, wax, yeast, honey and glycerol. Galleria pests were infected with fresh cultures of EPN. The infection process involved the release of Galleria onto large plastic trays moistened with the nematode suspension. Galleria died within 24 hours and were ready for release in the fields.
