Submitted to: The Canadian Entomologist
Publication Type: Peer reviewed journal
Publication Acceptance Date: 2/15/2002
Publication Date: 6/1/2002
Citation: Horton, D.R., Landolt, P.J. 2002. Orientation response of the Pacific coast wireworm (Coleoptera: Elateridae) to food baits in the laboratory and effectiveness of baits in the field. The Canadian Entomologist. 134:357-367. Interpretive Summary: Wireworms are pests of a number of irrigated crops in Washington state. Difficulties in managing these pests can be attributed largely to their subterranean habit, which makes the insect difficult to monitor and difficult to kill. In this study, we explored in laboratory and field assays whether certain food baits can be used to monitor wireworms. Laboratory trials showed that several food baits, including germinating seed of wheat and barley, sliced carrot, and moistened rolled oats attracted wireworms. Field trials with these same baits showed that the baits also attracted wireworms under more natural conditions. Moreover, there was good agreement between the laboratory and field trials in bait effectiveness. These studies indicate that wireworm populations can be sampled under field conditions using certain food baits, reducing the need for other, more time- and labor-intensive sampling methods. Also, our results suggest that baits might be useful in an attract-and-kill control program, if methods can be developed to add a killing agent to an attractant.
Technical Abstract: Assays were conducted in the laboratory and field to monitor response of Pacific Coast wireworm to food-baits. A glass plate assay was used in laboratory trials to study movement of larvae through soil in response to presence of food-baits, including germinating seeds of grains, moistened rolled oats, carrot, and potato. Trapping studies were done in the field with these baits to determine effectiveness under field conditions. In both laboratory and field trials, seeds of wheat and barley ranked highest in response by larvae. In the glass plate assays, 65-70% of wireworms contacted the wheat or barley seed baits within a two hr assay period. Corn seed and sliced carrot were also effective, with 60% of larvae contacting the baits. Rice, rye, and potato were contacted by 30-45% of larvae. Unbaited controls were contacted only infrequently (15-25%). Trapping studies were conducted in the field and showed that all food-baits captured more wireworms than unbaited traps. A second assay conducted in the laboratory showed that moistened rolled oats were contacted with a higher probability if oats were aged 72 hrs following wetting compared to oats used immediately following wetting. Field trials using baits composed of different rates of rolled oats showed little evidence of a dose response in capture rates, although all baits captured more wireworms than unbaited traps.