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oak apple gall

James Heal

oak apple gall

James Heal

Oak apple gall wasp

Living up to its name, the oak apple gall wasp produces growths, or 'galls', on oak twigs that look like little apples. Inside the gall, the larvae of the wasp feed on the host tissues, but cause little damage.

Scientific name

Biorhiza pallida

When to see

May to June

Species information

Statistics

Diameter of gall: up to 5cm
Common.

About

The oak apple gall wasp, Biorhiza pallida, is a tiny wasp that causes growths, or 'galls', on oak twigs. These galls can be found between May and June where the female has laid her eggs in the leaf bud. Inside the gall, there are a number of chambers, each housing a larva which eats its way out. Adults emerge in June and July.

How to identify

The oak apple gall wasp produces a large, rough, buffish-brown, apple-like gall that can be found on oak twigs.

Distribution

Widespread.

Did you know?

The oak apple gall wasp has a second generation: the females that emerge in spring mate and drop to the ground to lay eggs in oak roots, producing further galls.