insect damage

Each year in late spring and early summer, homeowners begin noticing strange growths on the leaves or stems and are concerned for the health of their trees. Several different types of galls are common on Nebraska trees, caused by the feeding or egg laying activities of insects or mites. Either the physical damage done by the insect or its salivary secretions as it feeds causes the plant to increase its production of plant hormones. These plant hormones cause abnormally increased plant growth in small, localized areas and result in the formation of a gall.