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Maple eyespot gall midge

Acericecis ocellaris[4]

The maple eyespot gall midge, also called the ocellate gall midge, is a tiny fly whose larva turns a spot on a maple leaf into a colorful bull's-eye. The damage is cosmetic and does not affect the health of the tree.[1][3]

Group
Insect
Order
Diptera
Family
Cecidomyiidae
US records
32 states
Sources
4 cited
Updated
2026-10-19
Maple leaf covered in round eyespot galls, each a yellow ring bordered in red to maroon around a red center
Maple leaf covered in round eyespot galls, each a yellow ring bordered in red to maroon around a red center. (c) Niki Robertson, some rights reserved (CC BY) — via iNaturalist, CC BY 4.0
On this page
  1. Identification
  2. Look-alikes
  3. Where it lives
  4. Biology
  5. Damage and signs
  6. Health risk
  7. Control
  8. Related profiles
  9. Common questions
  10. Sources

How to identify it

  • The galls are round spots about 1/4 inch across that start as small yellow-green circles and mature into a red center ringed with green, then red deepening to maroon.[1][2]
  • The colors show brightest on the upper side of the leaf; a single tiny, clear larva sits in the middle of the spot on the underside.[3][1]
  • The spots usually color up in June and later turn brown.[2]

Look-alikes

Look-alikeHow to tell them apart
Maple bladdergall miteMaple bladder galls are hollow, roughly spherical growths on short stalks on the upper side of silver and red maple leaves, while eyespot galls are colored, ringed spots, mostly on red maple.[2][1]

Where it lives

Extension and forestry agencies from Pennsylvania and Kentucky to Wisconsin describe it on their maples. Red maple is the preferred host, the galls also turn up on sugar and silver maple, and Penn State adds striped, mountain and Freeman's maple.[1][2][3]

US map: public records from 32 states since 1990 (GBIF).

Biology and life cycle

Adults are small flies that emerge in spring and lay eggs on the underside of maple leaves.[2][1][3]

Each larva feeds for about a week to 10 days, injecting a growth-regulating substance that makes the leaf form the colored rings around it.[2][3][1]

The full-grown larva, about 1/16 inch long, drops to the ground and spends the rest of the year in the soil, pupating and emerging as an adult the next spring.[3][1][2]

There is one generation a year.[2]

Damage and signs

  • The spots are cosmetic and don't affect the health of the tree.[3][2]

Health risk

It is a plant-feeding gall midge; Penn State, Kentucky and Wisconsin DNR mention no risk to people.[1][2][3]

Control

Prevention

No control is needed: Wisconsin DNR calls the damage cosmetic, Kentucky notes that no control is available, and each larva feeds for only a week or so before dropping to the soil.[3][2][1]

Common questions

Is the bull's-eye spotting on my red maple a disease?
No. It's a gall made by a tiny fly larva feeding under each spot, and it is cosmetic only.[3][1]
Should I spray the spotted leaves?
Spraying isn't needed or useful, since the larvae leave the leaf after about a week to 10 days and spend the rest of the year in the soil.[2][3]

Sources

  1. Penn State Extension, “Leaf Galls on Maple.” extension.psu.edu/leaf-galls-on-maple (accessed 2026-10-19)
  2. University of Kentucky Entomology, “Common Maple Galls, ENTFACT-404 (L. Townsend and E. Eliason).” entomology.ca.uky.edu/files/ef404.pdf (accessed 2026-10-19)
  3. Wisconsin Department of Natural Resources, Forest Health, “Gall Causes Bull's-eye Spots On Maple Leaves (L. Williams, July 3, 2025).” forestrynews.blogs.govdelivery.com/2025/07/03/gall-causes-bulls-eye-spots-on-maple-leaves/ (accessed 2026-10-19)
  4. iNaturalist, “Acericecis ocellaris taxon page (order and family).” www.inaturalist.org/taxa/320034 (accessed 2026-10-06)

Updated 2026-10-19. Built from sourced records. Spot an error? Tell us.