Compensatory Response of Cranberry to Simulated Damage by Cranberry Weevil (Anthonomus musculus Say) (Coleoptera: Curculionidae)

Abstract

Cranberry weevil (Anthonomus musculus Say), a key pest of cranberry (Vaccinium macrocarpon Aiton) in Massachusetts, deposits eggs in unopened flowers and often severs the flower pedicel from the peduncle. The compensatory response of cranberry to simulated cranberry weevil damage was investigated by severing the pedicel of unopened flowers with scissors. When intensity of damage was varied on the cultivar Early Black, complete compensation was observed at three of four sites after removal of 33% of a peduncle's unopened flowers, but a ≈37% decline in number of fruit and weight of berries per peduncle was observed when 67% of unopened flowers were removed. When timing of damage was varied at sites planted to the cultivar Howes, no differences were observed when 50% of unopened flowers were clipped from a peduncle early versus late in preblossom peduncle growth. However, both the early and late clipping treatments resulted in a 30% decrease in the number and weight of berries per peduncle when compared with the no clipping treatment. These results suggest that cranberry has the ability to tolerate low to moderate levels of weevil damage, but a substantial data base will be required to determine any appropriate changes in threshold recommendations.