Invasion of the Pea Leaf Weevil
The pea leaf weevil is an invasive pest of concern in the Prairie Provinces. This insect was first recorded near Lethbridge, Alberta in 1997. In only fifteen years, it has expanded its range north to Edmonton, Alberta and east to Moose Jaw, Saskatchewan. The production of pea is threatened by this pest. In order to understand the impact of this invasive pest, we must be able to monitor it. A useful integrated pest management tool that could be developed for this pest is a semiochemical monitoring system. Semiochemicals are chemicals used for communication in biological interactions. Two important semiochemicals for the pea leaf weevil are aggregation pheromones and host plant volatiles. These compounds are likely involved in coordinating the movement of adult pea leaf weevils into a pea field in the spring and to overwintering sites in the fall. A trapping system utilizing synthetic copies of these semiochemicals, therefore targeting the pea leaf weevil, would be useful for monitoring the ongoing invasion of this pest. Semiochemical monitoring systems are useful pest management tools because they are highly specific to the target insect, require relatively few chemicals to be placed in the field, and are difficult for insects to become resistant to. The objective of this study was to determine an optimal lure for attracting the pea leaf weevil in pea fields. We tested the attractiveness of two doses of pheromone in each of two release devices, with and without host volatiles. We found that pea leaf weevil attraction to the lure does not differ between the two doses or release substrates of aggregation pheromone tested. However, lures incorporating host plant volatiles were significantly more attractive to pea leaf weevil adults than aggregation pheromone alone.