March 9, 2010
FOUND THIS INTERESTING GALL ON SAGEBRUSH (ARTEMESIA TRIDENTATA) IS THIS THE WOOL SOWER CALLIRHYTIS SEMINATOR OR RHOPALOMYIA?
Galls, unusual growths on plants, are often caused by insects, but there might be other reasons that the plant tissue becomes distorted and produces the odd growths. There is a nice online piece on Gall Making Insects by John A. Byers that has good information. This is neither a Wool Sower Gall and we are not certain if this growth on sage is caused by a Midge in the genus Rhopalomyia without doing additional research. We did find a paper online that was published by the Journal of the Kansas Entomological Society that mentions, but doesn’t picture, a Fruit Fly, Eutreta diana, that is called a Sage Stem Galling Fly. We found the fly pictured on the Diptera Site, but again, a photo of the actual Gall produced by the fly has eluded us.