Delayed action of an entomophagous nematode ( Heterorhabditis sp.) for grass grub control

Abstract

The entomophilic nematode {IHeterorhabditis} sp. was applied to pasture in New Zealand for the control of the scarabaeid {ICostelytra} {Izealandica} at a rate of 0.5M/m2 on 11 January 1984. Six weeks after application, 9% of {IC}. {Izealandica} larvae were dead due to nematode infection, but nematodes had a negligible effect on the population 9 and 12 weeks after application. In January 1985, however, 14% of 1st- and 2nd-instar larvae were infected by nematodes and the population was signficantly reduced. In February, May and June 1985 the nematodes had spread throughout the site and 56% of larvae in an adjacent area were dead due to nematode infections