Plant Parasites of Europe

leafminers, galls and fungi

gallers on Amaranthus

Dichotomous table for gallers on Amaranthus

by Hans Roskam

1a On above ground organs, sometimes encroaching onto upper part of main root => 2

1b Side roots with nodular or spindle-shaped swellings. Amaranthus spp.: Meloidogyne hapla

= The cyst-developing eelworm Heterodera schachtii has been recorded on several Amaranthus species

2a On stems or leaves => 3

2b Flowers of single panicles ± enlarged, thickened and reddened. Bracts cylindrically thickened, rolled, inflated, wrinkled. A. retroflexus: Inducer unknown; possibly galls with oospores of Wilsoniana bliti.

3a Shoot tips ± stunted. Leaves ± clustered, margins deflected, sometimes contacting; leaf blades arched upwards, ± curled and partially discoloured. Amaranthus spp.: Aphis fabae

3b Axial parts, sometimes also flower parts, variously swollen, also ± distorted. Inside tissue is a mycelium which develops oospores. Mature oospores dark brown-red to blackish translucent. Amaranthus spp.: Wilsoniana bliti

Last modified 22.vi.2020