Compensatory ability of strawberries to bud and flower removal: implications for managing the strawberry bud weevil (Coleoptera: Curculionidae)

The strawberry bud weevil, Anthonomus signatus Say, is considered a major pest of perennial matted row strawberry plantings in the eastern United States with an economic threshold of 2 clipped buds per meter row. No relationship was found between the number of naturally clipped buds per meter (range, 0-20) and subsequent yield over 2 field seasons for the strawberry cultivar 'Earliglow' indicating the potential for compensatory fruit production. In field experiments, flower buds or open flowers were removed by hand and the impact on yield for 3 strawberry cultivars measured. For the cultivar 'Jewel', removal of all primary or secondary buds did not result in a significant decrease in yield relative to control plots, although the removal of all tertiary plus higher order buds did result in a significant decrease. For 'Seneca' and 'Kent', removal of all primary, secondary, or tertiary buds did not significantly decrease yield compared with control plots. Compensation to bud removal was achieved by increasing fruit weight of remaining buds and increasing the number of higher order buds matured. When similar treatments were applied to flowers, we observed a negative impact on yield for all 3 cultivars. In 1996 we assessed the benefit of treating for strawberry bud weevil when injury reached the economic threshold at 7 commercial strawberry operations in upstate New York. Untreated plots had significantly more clipped buds per meter than treated plots (13 versus 4), however, there was no difference in yield.