Cypress twig gall midge

Natural History
Galls caused by cypress twig gall midge
Photo credit: Russel F. Mizell III, University of Florida

The cypress twig gall midge (Taxodiomyia cupressiananassa) infests bald cypress (Taxodium distichum), pond cypress (T. ascendens) and Montezuma cypress (T. mucronatum) in the U.S. from Illinois to Florida and Louisiana. The adults are tiny flies that lay eggs in developing foliage. A gall forms as larvae develop and up to 16 eggs are found per gall. The insect overwinters as larvae in galls that drop from trees during the winter. The pupae develop in spring and adults emerge in summer. Up to 2 generations per year are common in Florida. Many predatory insects prey on the cypress twig gall midge and certain genetic lines of bald cypress have resistance to the insect.


 

Identifying Characteristics

Identifying the injury: Galls, globose to elongated in shape (up to > 3 cm long x 2 cm in width) are present by early summer on leaflets and are whitish in color. In fall the affected leaves often turn brown earlier than unaffected foliage and the galls become brown as well. This makes affected trees unsightly.
Identifying the insect: Adults are tiny flies (about 1.5-2 mm long) with clear wings. Eggs are orange, translucent and there are usually 15 eggs per cluster. Larvae are orange-red and pupae are bright orange with wings appressed to the body.
Susceptible trees: The cypress twig gall midge affects bald cypress (Taxodium distichum), pond cypress (T. ascendens) and Montezuma cypress (T. mucronatum).

 

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