Plantparasieten van Europa

bladmineerders, gallen en schimmels

gallers on Helianthus

Dichotomous table for gallers on Helianthus

by Hans Roskam

1a On above-ground parts => 2

1b Roots with almost rotund swellings, up to 4 mm long, sometimes clustered. H. annuus: Meloidogyne hapla

= Heterodera schachtii is known from H. annuus

2a Galls on root collar or on stem. The inducers are inside the galls => 4

2b Malformations predominantly on leaves. The inducers live on the surface of the malformations => 3

3a Leaves variously curled or bulging; malformations by aphids. Helianthus spp.:

a Brachycaudus helichrysi

b Aulacorthum solani

c Aphis fabae

3b Leaf blades of young plants over extensive parts and in various ways bent downwards, curled, and dark green close to the froth-covered nymph. Helianthus spp.: Philaenus spumarius

3c Dull white spots, pustules, even crusts on underside of leaves, largely consisting of a mass of conidia. H. annuus: Pustula helianthicola

4a Up to walnut- size or extensive, rugose proliferations on root collar or the basal stem parts. H. annuus, tuberosus, etc.: Agrobacterium tumefaciens

4b Spongy swellings of various shape on stems, petioles, leaf veins of young plants. H. annuus, tuberosus: Ditylenchus dipsaci

Laatste bewerking 21.v.2020