Bug FAQSpiny Witch-Hazel Gall Aphid
Hamamelistes spinosus · Order: Hemiptera · Family: Aphididae
Also called: witch hazel gall aphid
Spiny witch-hazel gall aphids make elliptical galls on birch buds that are about 21 mm long and 10 mm wide, covered in curved spines. They are found on eight birch species across North America, from Mexico to Canada, and the galled leaves often turn yellow or red. Eggs are laid in witch-hazel galls, overwinter there, hatch in spring, and the overall life cycle spans roughly two years.
Source: Wikipedia
How to recognize it
The galls are modified flower buds that are somewhat elliptical with a gradually tapering stalk. Their surface is covered with curved spines.
Source: Wikipedia
Size
Average length including stalk is about 21 mm and average width about 10 mm.
Source: Wikipedia
Is it a pest in the house?
Leaves with galls often change color to yellow or red.
Source: Wikipedia
Where it lives
They have been recorded on eight birch species, including B. pendula and B. papyrifera.
Source: Wikipedia
What it eats
Aphids feed on leaf buds, inducing galls that protect their young. Nymphs feed on the leaf tissue.
Source: Wikipedia
Life cycle
The full cycle typically lasts about two years.
Source: Wikipedia
When you see it
Eggs overwinter in galls and hatch in spring.
Source: Wikipedia
Where it comes from
The species occurs across North America, from Mexico up through Canada.
Source: Wikipedia
Where it is found in the US
Recorded in 35 of 51 states and DC. Most records: Massachusetts, Virginia, New York, Pennsylvania, Maryland, Wisconsin, Ohio, Illinois.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do the galls look like?
They are elliptical buds with a tapering stalk and are covered in curved spines.
Source: Wikipedia
Which trees are affected?
Eight birch species can host the galls, and the leaves often turn yellow or red.
Source: Wikipedia
How long does the life cycle last?
The aphid’s life cycle is about two years, with eggs overwintering in witch-hazel galls and hatching in spring.
Source: Wikipedia
Where is this aphid found?
It is native to North America, ranging from Mexico to Canada.
Source: Wikipedia
Same family (Aphididae)
Melon AphidAphis gossypiiDamages trees, gardens or crops
Oleander AphidAphis neriiDamages trees, gardens or crops
Witch-hazel Cone Gall AphidHormaphis hamamelidis
Beech Blight AphidGrylloprociphilus imbricatorDamages trees, gardens or crops
Rice Root AphidTetraneura nigriabdominalis
Manzanita Leafgall AphidTamalia coweniSources
- Wikipedia: https://en.wikipedia.org/wiki/Hamamelistes_spinosus
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 2026-10-23.