The form described below was reared from deformed gooseberry buds, Ribes grossularia, in May, 1911, by J. S. Houser of the Ohio Agricultural Experiment Station. The material was collected at Camp Chase.

The plant is injured by the insect working during the larval stage in the terminal buds of spurs and branches, causing the bud to become abnormal both in size and structure. The bud scales increase greatly in numbers and size and, lying closely one upon another form a gall somewhat resembling in miniature the pine-cone willow galls so commonly encountered upon the tips of willow twigs. The injured bud is incapable of producing normal leaves and the plant, striving to maintain itself, develops secondary buds within or about the first and these, in turn, becoming infested, there is formed ultimately a large knot or cluster of galls. A typical cluster is illustrated in figure 1. Occasionally the injured cluster succeeds in putting out feeble growths which usually take the form of undersized twigs. Such a cluster, starting to develop, may be seen in figure 2. These growths appear at the end of the_first or second season as illustrated by figure 3. As a rule, however, this secondary-, "witch-broom" like growth does not develop, and one finds the infested plant with numerous, large, rounded gall-clusters located on any part of it as shown by figure 4.

Enlarged, deformed bud

This species forms an enlarged cluster of buds with greatly increased size and number of scales. Infested buds are killed. Witches brooms may later develop withen sceondary buds at the base of a gall send forth new growth. larvae overwinter in buds and pupate there in the spring. Adults emerge in May.

Host: Ribes grossulariae
Distr: Ohio