CONTROL OF INSECT PESTS WITH ENTOMOPATHOGENIC NEMATODES I. Control of Weevils with Entomopathogenic Nematodes

Entomopathogenic nematodes in the genus Steinernema and Heterorhabditis have been successfully commercialized as biological control agents for a variety of curculionid species. Nematode-based products have been introduced for: 1) root weevils, Otiorhynchus spp. 2) billbugs, Sphenophorus spp. 3) the apopka weevil, Diaprepes abbreviatus, and 4) the citrus root weevil, Pachnaeus litus. Several other Curculionidae species and other closely related families are potential candidates for future commercial introductions. Gaugler and Kaya (1990) recently published a complete review of current knowledge of entomopathogenic nematodes. Klein (1990) gave a condensed introduction regarding nematode efficacy to the order Insecta. The intent of this paper is to provide a brief overview of entomopathogenic nematode efficacy against weevils, and the recent technological developments which have made possible the commercial success of nematode-based products. Entomopathogenic nematodes in the genus Steinernema and Heterorhabditis and their associated bacteria (Xenorhabdus spp.) have been successfully commercialized as biological control agents for a variety of curculionid species. They can kill hosts rapidly, are easy to apply, and are exempted from federal and local registration requirements in most countries because of their safety to mammals and plants (Georgis et al. 1991). Difficulties in production, storage, formulation, quality control, and application technology limited their commercial success in the past. Recent public pressure to limit environmental contamination associated with chemical insecticide use has resulted in a dramatic increase in research conducted by scientists in government, universities and industry to overcome some of these technical difficulties (Smith et al. 1992). There are now three major biotechnology companies that have been successful in introducing nematodebased products into some commercial and consumer markets.