Eucalyptus Gall Wasps are tiny fly-like wasps. They're parasitic wasps, which means they require a living host to reproduce successfully.
Ophelimus spp. are solitary; unlike yellowjacket wasps who live in social nests with multiple individuals. They use the leaves of Eucalyptus to lay their eggs.
Eucalyptus plants respond to infestations by producing abnormal bumps, called galls. The wasp's larvae develop inside the gall until mature, emerging as adult wasps.
Ophelimus spp. is most damaging in Eucalyptus plantations, and less so in gardens. Usually, the first symptom noticed is infested leaves falling prematurely.