Bug FAQAustralian Eucalyptus Leafgall Wasp
Ophelimus maskelli · Order: Hymenoptera · Family: Eulophidae
Also called: Eucalyptus Gall Wasp, Gall wasp
Source: Wikipedia
The eucalyptus leaf-gall wasp is about 1 mm long. It originates from Australia and New Zealand but has spread to many other regions, including the Mediterranean and California. Females lay eggs on young eucalyptus leaves; the larvae make galls that can lead to heavy defoliation.
Source: Wikipedia
How to recognize it
Ophelimus maskelli is commonly called the eucalyptus gall wasp.
Source: Wikipedia
Size
It measures roughly 1 mm in length.
Source: Wikipedia
Is it a pest in the house?
Heavy infestations cause extensive galling, leading to widespread leaf loss and reduced growth of eucalyptus trees.
Source: Wikipedia
How to get rid of it
Biological control using parasitoid fairy wasps, especially Closterocerus chamaeleon and Stethynium ophelimi, has successfully reduced populations in the Mediterranean.
Source: Wikipedia
What it eats
Females lay eggs on immature eucalyptus leaves, and the developing larvae create galls on the leaves.
Source: Wikipedia
Life cycle
In spring the wasps can emerge in huge numbers, forming visible clouds that are a nuisance.
Source: Wikipedia
When you see it
Large emergences occur in the spring.
Source: Wikipedia
Where it comes from
It is native to Australia and New Zealand.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: California, Arizona, Florida, Hawaii.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: introduced in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What damage do they cause?
Their larvae make galls on eucalyptus leaves, which can lead to heavy defoliation and reduced tree growth.
Source: Wikipedia
How can I control them?
Releasing specific parasitoid wasps, such as Closterocerus chamaeleon and Stethynium ophelimi, has been effective in cutting their numbers.
Source: Wikipedia
Same family (Eulophidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Ophelimus_maskelli
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.