Comparisons Between Blacklight and Pheromone Traps for Monitoring the Western Bean Cutworm (Lepidoptera: Noctuidae) in South Central Idaho

Abstract

Blacklight traps have been used since 1958 in south central Idaho to monitor western bean cutworm, Loxagrotis albicosta (Smith), populations and to predict damage on beans and corn. In 1982, 1983, and 1984, two types of pheromone traps were compared with the standard blacklight trap. Pheromone traps were a handmade water-bucket trap and a modified Japanese beetle trap. For the overall trapping season, catches from both pheromone traps correlated well with catches from blacklight traps and with one another. In addition, total catches up to the time of peak moth flight from all three traps correlated well with percentage of damage to both bean pods and seeds. However, average daily catch per trap showed a high amount of variability and lack of association between moth counts and damage. Traps located on the west side of fields at 1.2 m above ground provided the best catches. Results of this study suggest that pheromone traps can be used to replace the standard blacklight trap, which is expensive, nonselective, bulky, and dependent upon a power source.