| The entomopathogenic nematode, Heterorhabditis megidis Poinar, Jackson, and Klein, 1987 and its mutualistic bacterium, Photorhabdus luminescens (Thomas and Poinar 1979) Boemare, Akhurst, and Mourant comb. nov., are biological control agents of insect pests. An isolate, H. megidis H90, obtained from the Okanagan Valley, British Columbia, was evaluated in laboratory and greenhouse experiments for infectivity and efficacy against several forest insect pests. Some comparative experiments were conducted using the nematode Steinernema carpocapsae strain All obtained as Biosafe;Results from Petri plate tests using larvae of the greater wax moth, Galleria mellonella (a nematode-susceptible test insect), showed that temperature influences the number of, and speed at which nematodes enter the insect, and development within the insect. Compared to H. megidis, S. carpocapsae had a faster infection rate. Although infectivity from both H. megidis and S. carpocapsae occurred at 8;Petri plate experiments involving the Douglas-fir cone gall midge, Contarinia oregonensis (Foote) and the spruce cone maggot, Strobilomyia appalachensis Michelsen, resulted in 27 and 56% mortality, respectively. Mortality was influenced by the temperature, dosage, and the developmental stage of the insect. In Petri plate experiments using eastern spruce budworm, Choristoneura fumiferana Clemens, and root weevils, Otiorhynchus ovatus L., mortality of 100 and 30% respectively, was obtained. Experiments using fungus gnats, Bradysia sp., resulted in 91% mortality in Petri plates, and a minor decrease in the number of adults which were trapped under greenhouse conditions. (Abstract shortened by UMI.). |
