|Gall wasps|| (Mossy rose gall, Diplolepis rosea;
Spiny rose gall, Diplolepis bicolor)
Wasp galls are abnormal plant growths resulting from activity of the tiny, non-stinging cynipid wasps.
Photo 18: Mossy rose gall
Control is best done by pruning out galls before the wasps have matured and emerged from the gall. Since adults emerge from the old galls in spring, prune out the galls after the leaves drop in fall, cutting below the gall and above a bud. For leaf galls, pick up fallen leaves. Removing the galls from the garden may not totally eliminate future problems if adult wasps fly in from nearby areas. Timing for insecticidal treatment of these wasps is difficult and not suggested.
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