Plant Parasites of Europe

leafminers, galls and fungi

gallers on Fragaria

Dichotomous table for gallers on Fragaria

by Hans Roskam

1a On above-ground plant parts => 2

1b Nodular swellings on roots. Fragaria spp.: Meloidogyne hapla

1c Small solid swellings, often curved and twisted, at the tips of lateral roots; other parts of roots sometimes thickened. Slender and transparent adult eelworms, 1.5–12 mm long, feed on outside of root. Fragaria spp.: Longidorus sp. and/ or Xiphidinema sp.

2a Malformations are restricted to single or several plant parts or, if extending over larger parts are not “cauliflower”-shaped => 3

2b Complete plant ± severely disfigured; shoot stunted, thickened, curved; the many branchings ± fasciated or otherwise coalesced; leaves stunted, inflorescences disfigured; ‘cauliflower disease’ of cultivated strawberries. Fragaria spp.: Putatively combined infestation of: Rhodococcus fascians and/or Aphelenchoides fragariae

3a Flowers disfigured, calyx leaves elongated, corolla distinctly reduced and ± pale green. Flowers mainly sterile, ± clustered because of stunting of stalks. On cultivated strawberries, also on clover. Virus disease: “Flower greening of strawberry”

3b On stems, petioles or leaves => 4

4a Malformations mainly on leaf blade => 6

4b Galls on stems or petioles => 5

5a Oval to spindle-shaped or bulging swellings with single to several rimmed depressions, containing a scale insect. Fragaria spp.: Planchonia arabidis

5b Spongy swelling lacking a gall chamber, mainly at stem base or petiole. Fragaria spp.: Ditylenchus dipsaci

6a Leaf blade variously curved or crumpled => 8

6b Leaf blade with pouch galls or erinea => 7

7a Leaf blade on upperside with nodule-shaped pouch galls up to 1.5 mm long, red, ± pubescent; exit hole on underside. F. moschata, vesca, viridis: Fragariocoptes setiger

7b On leaf underside, spots with erinea of reddish discoloured multicellular, terminally blunt hairs. Fragaria spp.: Phytonemus pallidus subsp. fragariae

8a The inducer lives on the surface of the malformations => 9

8b Various curvings of often short-stalked leaves, mainly on stunted plants. Fragaria spp.: Aphelenchoides fragariae

9a The ± crumpled, locally deep-green leaf blades variously deflected and clustered. Containing a froth-covered nymph on underside. Fragaria spp.: Philaenus spumarius

9b Variously shaped malformations, often associated with curling, sometimes gall-like on yellow-green discoloured, ± vitreous, often severely stunted inner leaves. Caused by tarsonemid mites, living in the folds. Plants stunted. “Curling disease”. Fragaria spp.: Phytonemus pallidus

Last modified 20.iv.2020