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Galls made by aphids, adelgids, phylloxerans, psyllids, and midges occur on many different plants. Galls are abnormal growths of plant tissue induced by insects and other organisms. Gall-making parasites release growth-regulating chemicals as they feed, causing adjacent plant tissues to distort and form a gall. The parasite feeds and develops within the relative security of the gall. Most of these parasites and their galls are harmless to trees and plants, but a few are pests.
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June 2, 2022