Plant Parasites of Europe

leafminers, galls and fungi

gallers on genus Aethusa

Dichotomous table for gallers on Aethusa cynapium

by Hans Roskam

1a On stems or leaves => 2

1b Centre of umbel or stalk of umbel ± swollen, club-shaped. Inner wall covered with mycelium. Contains a red larva. Lasioptera carophila

2a Large parts of plant disfigured => 4

2b Stem or leaves with localised galls => 3

3a Stem, and stalks of partial umbels with lateral rounded swellings, 2–3 mm long; with an irregular larval chamber inside. Unidentified beetle

3b Minor, weak bulge-like archings on leaf veins, rachis, -stalk or stem; soon bearing spermogonia and primary uredinia. Puccinia nitida

4a Curled leaf blades caused by aphids or cercopids => 5

4b Younger plants severely stunted. Leaf axis and possibly basal stem parts distinctly shortened, spongy, pale-green, with undulate-wrinkled surface. Ditylenchus dipsaci

5a Larger composite leaves ± nest-like or bell-shaped converged downwards; strongly curled, deep-green close to the froth-covered nymph. On developing plants often several leaves on locally markedly shortened stems are similarly disfigured. Philaenus spumarius

5b Leaves remaining small, rolled, closely accumulated, dark-green discoloured; bearing green aphids. Cavariella aegopodii and/or C. pastinacae

= Also living in summer on several umbellifers is the aphid Hyadaphis foeniculi which might be responsible for the malformations

5c Several leaves stunted and curled; tips deflected. Leaf blades ± knobby swollen, not discoloured. On underside several flat froth-covered nymphs surrounded by a border of white wax hairs. Trioza apicalis

Last modified 17.xi.2023