Plant Parasites of Europe

leafminers, galls and fungi

gallers on Eupatorium

Dichotomous table for gallers on Eupatorium cannabinum

by Hans Roskam

1a Malformations of leaves at the tips of the shoots => 3

1b Swellings of the shoot stems => 2

2a Spindle-shaped or cylindrical swelling in main- or side stem near a node or in axils of flower peduncles, about 10–15 mm long, with round opening when mature; one or several yellowish-white caterpillars with a yellow-brown head, in pith with frass. Upper stem parts stunted, often conspicuously discoloured. Adaina microdactyla

2b Stem mainly close to the ground, with differently situated and expanded, sometimes curved swelling. A scale insect in a depression. Planchonia arabidis

3a Malformations by aphids or spittlebugs => 4

3b Leaves on stunted shoot tips clustered, rolled upwards, rudiments of inflorescences stunted. All infected parts conspicuously white pubescent. Aceria eupatorii

4a Aphid malformations => 5

4b Leaf segments nest-like converging, the leaf blades curled, dark green close to the froth-covered nymph. Philaenus spumarius

5a Leaves on ± stunted shoots more or less stunted, the margins curved downwards, the leaf blade ± curled. Aphid 1.5–2 mm long, bright yellowish to yellow green, with short conical yellowish to green cauda. Brachycaudus helichrysi

5b Similar malformations by dark green aphids; siphunculi and cauda dark to black. Aphis frangulae

Last modified 20.v.2020