Compensatory response of cranberry to early season apical meristem injury by a gall inducing fly, cranberry tipworm (Dasineura oxycoccana)

The response of plants to apical meristem injury depends on a number of factors including growth stage, time of injury, and frequency of attack by the herbivores. In woody plants, the response to injury in terms of reproductive output can range from no effect after defoliation to overcompensation. Cranberry tipworm, Dasineura oxycoccana Johnson, is a tiny gall midge about 2 mm in length and native to the cranberry growing regions of north-eastern US. The cranberry plant produces recumbent woody runners that send out short vertical peduncles, which are commonly called uprights and may bear flowers. Feeding by tipworm larvae results in the death of apical meristem and uprights may respond by sending out one or more side-shoots from axillary buds. We conducted a field study to determine the compensatory response (both reproductive and vegetative) of cranberry uprights to early season tipworm feeding injury by investigating its impact on fruit-set, yield per upright, and production of side-shoots.