Citrus gall wasp







Bruchophagus fellis



The adult wasp is shiny, black and very tiny, making it difficult to see. This wasp does not fly very well but it is easily carried by the wind.

Adult size: 3 mm

Out and about

They emerge as adults in spring, and by late spring-early summer the adults are gone. This is a native of Australia found mainly in warmer coastal areas but more recently further inland.

Reproduction and Life cycle

They mate early-to-late spring. The female lays her eggs at the beginning of summer with the next generation emerging the following spring. After the start of summer the wasp is not about.

To deter

To control

It is best to remove the galls as soon as they are noticed. If there are holes in the galls then the wasps have already emerged. The tree may need to be cut back quite hard if there are a lot of galls and if they are causing the tree problems.They are difficult to control but the following methods are worth a try. - Limit the use of high-nitrogen fertilizer in spring as this will produce an abundance of new growth in a short space of time which will attract the wasp. Instead, add fertilizer late summer, late autumn and mid- winter. - Protect the new growth with neem or other oil spray- may deter the female from laying eggs. - They are attracted to yellow, so sticky paper traps around the tree in late winter may catch some. Be careful not to leave them there too long as they will also catch beneficial bugs. - If there are no holes in the galls then the wasps are still inside and removing these will reduce next year’s population. However, if the galls have holes in them, then the wasps have emerged and cutting off the gall will not help. - As the larvae spend a few months feeding within the plant, a neem drench around the plant during autumn and winter, prior to the wasp laying its eggs, may have some effect.

Plants to repel

Plants to attract


Gall wasp parasite A couple of species of wasp in the genus Megastigmus are parasitoids of the gall wasp larvae. Adults appear at the end of spring or start of summer when eggs have been laid by the gall wasp. The female is yellowish brown in colour with red eyes, whilst the male is black with brown underneath. The female lays her eggs in the eggs of the gall wasp. The gall wasp egg hatches first and then the parasitic wasp egg hatches and develops within the gall wasp larva.
Why they are a Pest
A ‘gall’ is formed when the female wasp lays her eggs in a branch of the tree, in which the young wasps develop. It will not actually kill the tree but it will weaken it, effecting the growth and productivity. The host tree for this wasp is the native finger lime but it will lay eggs in other citrus trees.