PestLow Severity

Cynipid Gall Wasps

Cynipidae family (various species)

Small wasps that create distinctive galls on oak trees through their feeding and development activities. They produce two types of galls: spherical corky galls from asexual generations and smaller wheat-kernel-like galls from sexual generations. While generally not seriously damaging, numerous galls can be aesthetically disfiguring.

Peak Season: Adult emergence: December (asexual generation)Egg laying: Early spring on swelling budsSpring galls: Develop as buds openSummer galls: Form from dormant eggsFall appearance: Large spherical galls most noticeableOverwintering: Adults remain in galls through winter
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Cynipid gall wasp galls on oak showing various spherical and specialized forms

Identification & Symptoms

What to Look For

Spherical, corky galls 1/8 to 1 inch diameter on twigs and branches
Pink to pinkish-brown galls when first formed
Small beige-colored galls resembling wheat kernels on leaves
Various specialized gall types: gouty oak galls, wool sower galls, oak apples
Hedgehog galls with orange-colored hair-like projections
Woody twig galls and spongy leaf galls

Potential Damage

Aesthetic disfigurement when galls are numerous
Generally minor impact on tree health
Potential twig weakness from large woody galls
Disruption of normal branch growth patterns
Secondary infections possible through gall openings

Lifecycle

Complex alternating sexual and asexual generations. Asexual females emerge in December, laying eggs on leaf buds. Spring larvae create small wheat-like galls producing both male and female adults. After mating, females lay dormant eggs (3-5 months) that create the larger spherical galls. Development may take 2+ years to complete.

Professional Treatment Approach

1

Generally no treatment necessary due to minimal damage

2

Prune and destroy heavily galled branches if aesthetically objectionable

3

Maintain tree health to minimize stress

4

Monitor for secondary pest or disease issues

5

Remove galls before adult emergence if control desired

Recommended Mauget Products

No chemical treatment typically needed

Professional-grade treatment specifically effective against cynipid gall wasps.

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