Abstract: The susceptibility of main species of white grubs in northern part of China to four strains of entomogenous nematodes was observed in the laboratory. The result indicated that Holotrichia morosa Watcrh was susceptible to Steinernema glaseri NC34, and the morbidity would be 90.0-93.3% when the nematodes/grubs ratio in population was 2000-4000 : 1. The test also showed that the infecting potential of Steinernema sp. NC513 was a little less strong and that of S. feltiae Agriotos and of S. bibionis was still less. Holotrichia oblita (Fald.) was not susceptible to above four trains of nematodes. It was found that the nematodes was able to independently move and seek hosts in soil. The hosts could be infected after contact with the entomogenous nematodes for 48 h. The nematodes developed and reproduced in the host body, depending on uptake of nutrients from its host, and when the host-grub skin was broken up, they would get into the soil again and seek new host.

Key words: White grub, Entomogenous nematode, Sesceptibility