Postdoctoral Associate Cornell University Geneva, New York
Wireworms (Coleoptera: Elateridae), are important pests of cereal crops in Montana, USA. Because of lack of effective control measures, alternative control methods such as biological control with entomopathogenic nematodes (EPNs) are required. This study was focused on evaluating efficacy of available and Montana native EPNs against sugarbeet wireworm, Limonius californicus (Mannerheim) in laboratory, field, and greenhouse. Out of ten available EPN strains, Steinernema carpocapsae (Weiser) (All and Cxrd) and S. riobrave Cabanillas, Poinar, and Raulston (355 and 7-12) were found effective in laboratory and shade house. However, the dose required to kill at least 50% L. californicus larvae was 200 infective juveniles/cm2. Further, Steinernema carpocapsae and S. riobrave in the form of infected Galleria mellonella L. cadavers were evaluated against wireworms (L. californicus and H. bicolor) in field. None of the four EPN strains were found effective in reducing wireworm populations or protecting crop yield in both spring wheat and barley fields. However, only one infected Galleria cadaver of S. carpocapsae (All and Cxrd) and S. riobrave 355 was able to kill wireworm larvae as well as reduce plant damage in greenhouse. The imidacloprid treatment enhanced the infection and killing ability of EPNs against L. californicus. Two Montana native EPN species, Steinernema feltiae (Filipjev) and Heterorhabditis bacteriophora (Poinar) were extracted and were evaluated against L. californicus in laboratory and shade house. Although, 50% mortality was observed due to S. feltiae isolates in laboratory, none of these isolates performed well against L. californicus in shade house.