WSU Extension

Hortsense

Honey locust
 
Disease
Honeylocust canker 
Powdery mildew 
Insect
Honeylocust pod gall midge 
Locust borer 



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Caption: Honey locust pod gall midge
Photo by: R.S. Byther
  
Honey locust : Honeylocust pod gall midge
(revision date: 3/22/2021)


Use Integrated Pest Management (IPM) for successful plant problem management.

Biology
The honey locust pod gall midge is a tiny orange gnat that lays its eggs on new foliage in the spring. The small pinkish or yellow-white maggots feed on the leaves, which become deformed, thickened, and pod-like in appearance. The larvae are sheltered inside the deformed leaves. Infested leaves may dry and drop from the tree. Small shoots may be killed. This is mainly an aesthetic concern, since the ornamental quality of the tree may be lost.
Management Options


Non-Chemical Management
  • Pick and destroy infested leaves, when practical, to help improve appearance.
  • Prune out dead twigs and branches.
  • Black locust (Robinia pseudoacacia) is not attacked. The honey locust (Gleditsia triacanthos) variety 'Shademaster' is reported to be less susceptible, but 'Sunburst' is very susceptible.
Select non-chemical management options as your first choice!

Chemical Management
IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides

The key to successful management is protection of new foliage with a registered insecticide. Sometimes repeat applications are needed, at 2-4 weeks, beginning late spring. Homeowners should not make foliar applications to trees over 10 ft tall. Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.
  • Bayer Advanced Vegetable & Garden Insect Spray RTS
    Active ingredient: cyfluthrin  |  EPA reg no: 72155-39
  • This list may not include all products registered for this use.
Images

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Caption: Honey locust pod gall midge
Photo by: R.S. Byther