The effect of pruning on blueberry stem gall wasp

Abstract

The influence of commercial pruning regimes on the survival of wasps inhabiting stem galls of lowbush blueberry (Vaccinium angustifolium Ait.) was studied in 1999 and 2000. Three commercial fields in Nova Scotia were used to examine the effect of mow pruning on wasp survival. Galls were removed from blueberry stems in fall 1999 and placed either above or within the leaf litter in a small blueberry plot or held at 2°C over the winter. Another group of galls was collected in spring 2000 from within and above leaf litter. Wasp emergence was not affected by any treatment showing that mow pruning has no effect on wasp survival. In a second study, mowing was compared to mowing plus burning in either fall or spring. Burning did not affect gall number, but did affect wasp emergence. The poorest emergence from galls was seen in spring burning and those burnt in the fall had lower emergence than from galls that were only mowed. Thus, a spring burn is recommended if growers are concerned about stem gall populations in their fields. © 2004 by The Haworth Press, Inc. All rights reserved.].