ABSTRACT: Knopper Galls, Which Adversely Affect Acorns of Native Oaks, Are Caused by The

ABSTRACT: Knopper Galls, which adversely affect acorns of native oaks, are caused by the non-native invasive wasp Andricus quercuscalicis. The wasp requires Quercus cerris (Turkey Oak) as an alternate host, and the gall has been known in Ireland since at least 1991, chiefly in the south and east. The first records of the Knopper Gall in Co. Limerick, at some 25 lowland sites in fifteen 10 km squares, are presented. The galls were found in 2006 and 2007on young and old Q. robur (Pedunculate Oak) and on Q. x rosacea, intermediates between Q. robur and Q. petraea (Sessile Oak); Knopper Galls were not found on Q. petraea. The Artichoke

Gall, caused by the native wasp Andricus fecundator, is widespread in Ireland. Previously known in Co. Limerick only from Adare, records are given for it occurring sparingly at four sites in the county on Q. petraea and at one site on Q. x rosacea in 2007.