Hormaphis cornu (on-betula)
The inducer of this gall is unknown or undescribed.
Hosts: Betula nigra
Detachable: integral
Color:
Texture:
Abundance:
Shape:
Season: Summer, Fall
Related: Hormaphis cornu (on-hamamelis)
Alignment: integral
Walls:
Location: upper leaf, lower leaf, between leaf veins
Form: leaf curl
Cells: not applicable
Possible Range:i
Common Name(s):
Synonymy: 
Our ID Notes may contain important tips necessary for distinguishing this gall from similar galls and/or important information about the taxonomic status of this gall inducer.
Gallformers ID Notes
“
H. cornu galls witch hazel, but does not produce true galls on its alternate host, birch. See https://content.ces.ncsu.edu/witchhazel-leaf-gall-aphid for photos of an "aleurodiform" [whitefly-like] generation of these aphids on birch.
The excerpt from von Dohlen & Stoetzel does not mention leaf curl on birch, but it is common for sap sucking by aphids and other Hemiptera to cause some leaf curl. More research is needed to explore whether the leaf curl on birch is distinctive enough for ID.
”- Gallformers Contributors: (2024) Gallformers ID Notes©
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