Plant Parasites of Europe

leafminers, galls and fungi

gallers on Comarum

Dichotomous table for gallers on Comarum palustre

by Hans Roskam

1a Galls on vegetative plant parts => 2

1b Flowers stunted, not opening, transformed into ± globular galls. Containing several orange larvae. Unidentified gall midge

2a Leaves strongly curled or with additional pubescence => 3

2b Many spots on both sides of leaf, up to 1 mm across, rotund to angular, usually slightly swollen dark-violet; on petiole developing sori appear as oblong-oval bulges. Nutritive cells distinctly enlarged, with solitary or several (2–4) resting spores. Physoderma comari

2c Leaves are hardly disfigured, but a slight change of colour is discernable.
Bactericera acutipennis

3a Leaves at infestation sites, mainly on underside of leaf, densely silk-like pubescent; grey on corresponding upper side, almost brownish on underside. Phyllocoptes roivaineni

3b Leaf midrib at infestation deflected, severely stunted. Leaflets clustered, nest-like bent downwards, locally strongly crumpled and dark green. Philaenus spumarius

Last modified 3.vii.2020