SEED LOSSES TO FEEDING BY LEPTOGLOSSUS-OCCIDENTALIS (HETEROPTERA, COREIDAE) DURING 2 PERIODS OF 2ND-YEAR CONE DEVELOPMENT IN WESTERN WHITE-PINE

The effect of feeding by western conifer-seed bug, Leptoglossus occidentalis Heidemann, on western white pine (Pinus monticola Dougl. ex D. Don) was evaluated at the USDA Forest Service Dorena Tree Improvement Center in western Oregon. We compared effects of feeding on cones caged to exclude seed bugs or to contain individual seed bugs for 3-wk periods during early (May) and late (July) stages of second-year cone expansion. Cone abortion was associated with early feeding. Total seed yield per cone was reduced 5-fold by early feeding compared with control levels. The numbers of partially filled seed and indistinct seed were increased by feeding late in the season. The number of filled seed was reduced 70-80% by seed bug feeding. Different effects of seed bug feeding at different times can be measured in controlled caging experiments, but further information is needed on L. occidentalis activity in orchards.