(Dasineura gleditschiae)
The larva of this tiny orange to black fly causes unsightly galls on honeylocust trees, especially the thornless varieties. The adult female midge begins laying eggs on new leaflets in the spring. When the eggs hatch the larvae feed on the tissue, causing the leaflet to fold over them and form a pod gall. As the larvae develop inside, the galls turn brown. The flies emerge to lay more eggs. Honeylocust produces new leaves over a long period, so the cycle may repeat itself up to 7 times annually. The galls are not usually damaging to the tree. However, the ornamental value of the tree is reduced when the galled leaflets dry up and drop prematurely. Twigs sometimes die back after repeated attack, but new shoots normally form at the base of the dead twigs.
Prune off dead twigs. Spray with an insecticide containing diazinon, malathion, or carbaryl in late May and again in late July.
Plant Care for Gleditsia