Plant Parasites of Europe

leafminers, galls and fungi

gallers on Amelanchier

Dichotomous table for gallers on Amelanchier

by Hans Roskam

1a On buds and shoot axis => 6

1b On leaves (or occasionally fruits for fungi) => 2

2a Galls ± bulge-shaped, usually yellowish, with patches of spores on upper side => 5

2b Malformations caused by animals => 3

3a Galled leaves not conspicuously clustered => 4

3b Terminal leaves clustered. A. ovalis: Dysaphis parasorbi

3c Leaves terminal on severely stunted shoots mainly on tip rolled downwards, usually densely clustered. Amelanchier spp.: Aphis pomi

3d Shoots with several leaves ± curved and variously obliquely downwardly curved along the midrib. Amelanchier spp.: Rhopalosiphum oxyacanthae

4a Leaf blade ± pod-like folded upwards along the midrib, thickened in the middle. A. ovalis: Unidentified gall midge

4b Leaf blade with many pocks, protruding on both sides of leaf. A. ovalis: Eriophyes aroniae

5a Leaves, sometimes also young shoots, with yellow, later on reddened in the middle, swollen, aecia bearing pads. Peridium cylindrical, 2–3 mm long, open above, deeply thread-like lacerate; lateral walls of cells with many tubercles of various shape and size. Amelanchier spp.: Gymnosporangium clavariiforme

5b Galls similar. Peridium usually oblong-cornicular, 3–4 mm long, conical apex, at first closed, then opening, slightly or not lacerate at margin; lateral walls of cells ± densely tuberculate, or very short, with obliquely running ridges. A. ovalis, asiatica: Gymnosporangium cornutum

6a On shoot axial parts => 7

6b Buds swollen, not opening; scales enlarged, thickened, densely white pubescent. A. ovalis: Eriophyes amelancheus

7a Bark of stems or branches with cracked cancer-like proliferations; with white powdered aphids in cracks. Amelanchier spp.: Eriosoma lanigerum

7b Major branches with spindle-shaped swellings. A. ovalis: Viscum album

Last modified 21.v.2020