Pear-Gall Wasp
Andricus sp.
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Hosts: Quercus gambelii

This wasp induces pear-shaped galls that usually occur in clusters of two to four at the terminal acorn buds of new branches on Gambel oak in late spring. Galls measure 5-8 mm long by 3-4 mm in diameter and are covered with tightly appressed hairs except where the gall has been contacted and the hair has been worn off.