Pathogenicity of an Entomogenous Nematode, Steinernema kushidai MAMIYA(Nematode: Steinernematidae), on Anomala cuprea(Coleoptera: Scarabaeidae).

Abstract

Laboratory and field experiments were conducted to study the infectivity and propagation of {ISteinernema kushidai} on {IAnomala cuprea} larvae. The nematode-infective juveniles (JIII) showed higher infectivity for the 3rd instar than the 2nd and 1st instar of {IA. cuprea}. When JIII were inoculated on the 3rd instar, as much as ca. 30,000 JIII were produced per larva on average. The JIII production increased with increased insect size. Survival of JIII was also investigated under various conditions. The survival rate of JIII stored in water exceeded 50% at 15 degree C after 3 months, and decreased to 50% in a month or less at 4 degree, 10 degree, 20 degree and 25 degree C, and to below 10% at 4 degree C. In sterilized soil, nematode infectivity remained high for up to 6 months at 15 degree C. When the JIII were applied once to the soil of a peanut field in mid-April at the rate of ca. 10-6/m-2, the infectivity remained high enough to kill {IA. cuprea} larvae for 8 months, but it became very low during winter. The nematode was adversely affected by treatments with insecticides (Diazinon and MPP, 500-2,000 ppm), but not with fungicide (Thiophanatemethyl, 500-2,000 ppm) and with herbicides (CAT and Glyphosate, 5,000-20,000 ppm). Twenty minutes or longer exposure of the nematode suspension to sunlight resulted in decreased survival of JIII. {IMetarhizium anisopliae} had no effect on the nematode