Plant Parasites of Europe

leafminers, galls and fungi

gallers on Helichrysum

Dichotomous table for gallers on Helichrysum

(see also Gnaphalium)

by Hans Roskam

1a On root collar, inner basal rosettes or on above-ground plant parts => 2

1b Spindle- or nodule-shaped swellings on roots, up to 5 mm long. Helichrysum spp.: Meloidogyne hapla

2a On upper stem parts, leaves or inflorescences => 4

2b Inside basal rosettes or on root collar => 3

3a Top of rosettes including an almost onion-shaped gall, up to 8 mm high and 5 mm wide. One larva inside. H. arenarium: Actinoptera discoidea

3b Globular or nodular, up to 1 mm long galls which are sometimes clustered and variously coalesced on root collar. The inside filled with initially bright-, later on chestnut brown spore masses. H. arenarium: Entyloma magnusii

4a On leaves and inflorescences => 6

4b On shoots => 5

5a Spindle-shaped swellings of the stems or inflorescence, up to 25 mm long. Later on the caterpillar bores downward in the pith over various length. H. arenarium: Unidentified lepidopteran

5b Spindle-shaped stem swellings about 6 mm long and 4 mm thick. Containing a single larva. H. arenarium: Actinoptera discoidea

5c Terminal leaves grouped in a subspherical mass of 10–15 mm in diameter, or terrminal bud swollen, ovoid or spindle-shaped (10 x 4.5 mm), covered with pubescent leaves. Large axial cavity containing a single larva. H. italicum, litoreum, pendulum, stoechas: Actinoptera mamulae

6a On inflorescences or capitula => 7

6b The middle part of single or several leaves variously bent downward and ± curled by froth-covered nymphs. H. bracteatum: Philaenus spumarius

7a Inflorescence stunted, bunched. Leaves ± rolled. Helichrysum spp.: Brachycaudus helichrysi

7b Capitula deformed; receptacle hardened. Containing a single larva. H. arenarium: Actinoptera discoidea

Last modified 14.v.2020