Pest profile

Cypress Twig Gall Midge

Taxodiomyia cupressiananassa · Diptera: Cecidomyiidae[3]

The cypress twig gall midge is a tiny fly whose maggots cause small, pineapple-shaped galls on the branchlets of bald cypress and pond cypress; the galls are unsightly but don't really harm the tree.[1][2]

Cluster of whitish, pineapple-shaped cypress twig galls on bald cypress
Cluster of whitish, pineapple-shaped cypress twig galls on bald cypress. (c) Chris Stahl, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0

How to identify it

  • Galls are oval, 3/4 to 1 1/4 inches long, and look like miniature pineapples; they start pink, turn light green and often look white from a powdery coating, then brown after the adults leave.[1][2]
  • Adults are tiny gnat-like flies under 1/8 inch, tan with clear wings and an orange-red (female) or tan-orange (male) abdomen.[1][2]
  • Maggots are light orange when young, becoming yellow to orange-red.[1][2]

Where it lives

It attacks bald cypress and pond cypress; NC State and UF/IFAS both cover it.[1][2]

US map: public records from 23 states since 1990 (GBIF).

Biology and life cycle

Adults emerge from mid May over an extended period, mate the same day and live only one to two days.[2]

Females lay eggs in clusters on young, succulent foliage, and the maggots cause the gall to form.[1][2]

Damage and signs

  • The leaf dies beyond the gall, and mature brown galls can be so numerous that branches droop.[1]
  • Outbreaks are sporadic; a heavily galled tree may have few galls in following years.[1]

Health risk

None to people or pets.[1][2]

Control

Sanitation

Collect and destroy fallen galls in autumn or early spring, before the midges become active.[1]

Biological control

At least four species of tiny parasitic wasps attack it and help keep it in check.[1]

Pesticides

Insecticides aren't recommended: the galls don't really harm the tree and there is no good practical treatment.[1]

Common questions

What are the little pineapple-shaped balls on my bald cypress?
Galls caused by cypress twig gall midge maggots.[1][2]
Do cypress galls hurt the tree?
Not really; they are unsightly, and the leaf dies beyond the gall.[1]
How do I reduce cypress galls?
Collect and destroy fallen galls in fall or early spring.[1]

Sources

  1. NC State Extension, “Cypress Twig Gall Midge.” content.ces.ncsu.edu/cypress-twig-gall-midge (accessed 2026-10-15)
  2. University of Florida IFAS Extension (Featured Creatures), “Cypress Twig Gall Midge, Taxodiomyia cupressiananassa (EENY-430).” ask.ifas.ufl.edu/publication/IN806 (accessed 2026-10-15)
  3. iNaturalist, “Taxodiomyia cupressiananassa taxon page (order and family).” www.inaturalist.org/taxa/133713 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.