How to Manage Pests

Pests in Gardens and Landscapes

Gall midges

Adult gall midges are tiny, delicate flies, often with long slender antennae.  They resemble fungus gnats and flies in certain other families.  Larvae are tiny yellow to orange maggots that can't be seen unless you cut the galls open. There are hundreds of species of gall midges, not all of them pests.  Each gall-forming species is specialized to feed on only one or a few closely related hosts.  Some common pests of flowers and ornamentals include the chrysanthemum gall midge, the violet gall midge, and the honeylocust pod gall midge. Other species of gall midges prey on aphids and are beneficial.

Damage

In gall-making species, larvae bore into tissue or cause tissue to form into galls that surround the larvae, which feed inside.  Galls are distorted and sometimes colorful swellings in plant tissue.

Solutions

For flowers in planting beds, clip off galls and distorted plant parts as soon as you see them, and remove them from the garden. If you have a severe infestation, you may want to remove all susceptible plants. Gall midges are difficult to control with insecticides.  

 

Adult honeylocust pod gall midge
Adult honeylocust pod gall midge

Female violet gall midge on curled violet leaf
Female violet gall midge on curled violet leaf


Statewide IPM Program, Agriculture and Natural Resources, University of California
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