Dichotomous table for gallers on Andromeda polifolia
by Hans Roskam
1a Malformations on expanded parts of shoot or on leaves => 2
1b Stem with rimmed depressions with causer under a 2.5 (3) mm long scale.
Chionaspis salicis
2a Single or several leaves with localised malformations => 3
2b Complete shoots infected, ± etiolated or ± disfigured witches’ broom-like. Leaves partially larger, partially smaller than healthy ones; hardly thickened; sometimes pale-green, often conspicuously reddened. At maturity of fungus the underside with white down of basidia. Exobasidium myrtilli
3a eaf blade ± keel-shaped curved, hardly thickened. Conspicuously rolled downwards at margin, ± reddish discoloured. Cecidophyopsis ruebsaameni
3b Leaf blades with expanded, strongly swollen, usually conspicuously reddened swellings. Twigs hypertrophied, leaves disfigured and discoloured reddish to violet. Exobasidium karstenii
3c Twigs not thickened, but leaves broadened and thickened, reddish. Exobasidium sundstroemii