Plant Parasites of Europe

leafminers, galls and fungi

gallers on Arctostaphylos

Dichotomous table for gallers on Arctostaphylos

by Hans Roskam

1a Malformations on stems and leaves => 3

= (For root swellings see Vaccinium)

1b Galls on lateral buds or on fruits => 2

2a Buds enlarged and disfigured. A. uva-ursi: Aceria jaapi

2b Young berries disfigured, prematurely reddened and dropping; often ± angular, split to the middle; lobes sometimes elongated, snout-like. Usually containing several orange-coloured larvae. A. uva-ursi: Unidentified gall midge

3a Malformations only on leaves => 4

3b Malformations of complete shoots, partially witches’ broom-like. Leaves smaller or larger than normal ones; sometimes arched, pale green or ± intensively brown-red coloured; partially with whitish down on underside. A. uva-ursi: Exobasidium uvae-ursi

4a Leaf blade with loose, ± discoloured, slightly succulent marginal downwards roll. Containing several orange-red larvae. A. uva-ursi: Unidentified gall midge

4b Larger or smaller segments strongly arched downwards, depressed on upperside; leaf blades sometimes groove-shaped; often conspicuously reddened. Infestation occasionally at shoot tips encroaching onto all parts. Axial parts swollen, leaves reduced, succulent thickened, spoon-like. Infected parts on underside of leaf blade at maturity of fungus covered with chalk-white layer. A. alpina, uva-ursi: Exobasidium vaccinii

4c Leaves with small thickened orange spots, sometimes also on thickened stems. A. uva-ursi: Exobasidium sydowianum

4d Leaves slightly enlarged and thickened, yellowish white to dark purple; shoots clustered, slightly elongated and deformed. A. alpina: Exobasidium angustisporum

Last modified 2.vi.2020