Bug FAQWillow Apple Gall Sawfly
Euura californica · Order: Hymenoptera · Family: Tenthredinidae
The willow apple gall sawfly lays its eggs inside leaves of arroyo willow, and the resulting gall protects the developing larvae. In some locations it can produce up to six generations each year, breeding continuously throughout the year.
Source: Wikipedia
Where it lives
It lives on arroyo willow where it deposits eggs in the leaves.
Source: Wikipedia
What it eats
The larvae feed inside the gall that forms around the eggs in willow leaves.
Source: Wikipedia
Life cycle
The species can have as many as six generations per year in suitable areas.
Source: Wikipedia
When you see it
It breeds year-round where conditions allow.
Source: Wikipedia
Where it comes from
It belongs to the common sawfly family Tenthredinidae.
Source: Wikipedia
Where it is found in the US
Recorded in 48 of 51 states and DC. Most records: California, Illinois, Ohio, Minnesota, Michigan, Alaska, Massachusetts, Oregon.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
Are they a problem for my garden?
The only known host is arroyo willow; they are not reported to damage other garden plants.
Source: Wikipedia
Same family (Tenthredinidae)
Turnip SawflyAthalia rosaeNuisance, not dangerous
Willow Redgall SawflyEuura proxima
Yellow-spotted MacrophyaMacrophya montanaDamages trees, gardens or crops
Saddleback Grass-cutterEutomostethus ephippiumDamages trees, gardens or crops
Cherry Slug SawflyCaliroa cerasi
Alder SawflyEriocampa ovataDamages trees, gardens or cropsSources
- Wikipedia: https://en.wikipedia.org/wiki/Euura_californica
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-22 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-22.