CONTROL OF SCARABAEID GRUBS WITH AN ENTOMOGENOUS NEMATODE, STEINERNEMA-KUSHIDAI

A new species of steinernematid, Steinernema kushidai was recovered fr om a soil sample collected in Hamakita City, Shizuoka Prefecture, Japa n. The nematode showed a significant lethal effect on several species of scarabaeid grubs. Application of 1,000 infective juveniles (IJ) of the nematode onto the soil in plastic cups where the 3rd instar larvae of the cupreous chafer were individually reared killed the larvae wit hin a few days. In applications of the nematodes on soil in a sweet po tato field, more than 100,000-200,000 IJ/m2 reduced the numbers of the sweet potatoes seriously injured by scarabaeid grubs. S. kushidai app lied on a sweet potato field and on a nursery of the Japanese cypress persisted for at least 2 years. The nematode could be propagated in vi tro on peptone or yeast extract-rich media.