Methods |
This experiment was conducted in southern Alberta where the pea leaf weevil is known to occur. Ten pea fields from six counties were selected (Figure 8). Along one edge of each pea field, nine pitfall traps (Figure 9) were placed 25 meters apart along a linear transect.
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One pitfall trap was an unbaited blank. The lures used in the remaining eight pitfall traps (Table 1) were every possible combination of aggregation pheromone dose and release substrate, with or without bean volatiles. We tested two doses of aggregation pheromone (21 and 42 mg) in each of two release devices (250 and 400µL eppendorf tubes). Lower doses were not tested because they would not last in the field for the entire flight period. Two release devices were tested to obtain four different release rates of aggregation pheromone. Host plant volatiles were not tested in the absence of aggregation pheromone because a pilot study performed in 2012 found that host plant volatiles were not more attractive than a blank control. Traps were checked weekly for six weeks during both the spring and fall flight periods.