organ parasitic mode stage note taxonomic group parasite
stem borer doubtful Yponomeutidae Argyresthia sorbiella
leaf scale Coccidae Pulvinaria hydrangeae
flower gall Cecidomyiidae Contarinia floriperda
leaf down doubtful Erysiphales Phyllactinia mali
leaf down Erysiphales Podosphaera aucupariae
leaf gall Aphididae Aphis pomi
leaf gall Eriophyidae Eriophyes pyri
leaf miner Coleophoridae Coleophora hemerobiella
leaf miner Gracillariidae Parornix scoticella
leaf miner Gracillariidae Phyllonorycter mespilella
leaf miner Gracillariidae Phyllonorycter sorbi
leaf miner Lyonetiidae Lyonetia clerkella
leaf miner Nepticulidae Stigmella sorbi
leaf pustule aecia Pucciniales Gymnosporangium cornutum
leaf pustule uredinia telia Pucciniales Ochropsora ariae

Organ

the part of the plant that most conspicuously is hit by the parasite

all buds: both flower buds and leaf buds
flower: also inflorescence
leaf: also needle, phyllodium, petiole
leaf bud: also unfolding young leaf
fruit: also seed
root: also root stock, runners
root collar: also the lowest part of the stem
stem: also culm, the lower part of the peduncle, in grasses also leaf sheath
systemic: the entire above-ground plant.

PARASITIC MODE

borer: larva living internally, almost no outwards signs
down: 0.5-2 mm high fungal down
film: very thin cover of fungal tussue
gall: swelling and/or malformation
grazer: feeding at the outside of the plant
leaf spot discoloured, often ± necrotic, generally not galled, sign of a fungus infection
miner-borer: larve initially makes a mine, lives as a borer later
pustule: plug of fungal tissue, generally brown-black and < 2 mm
stripe: longitudinal line of fungal tissue in a grass leaf
vagrant: (aphids, mites) living freely on the plant, at higher densitiy causing malformations.

IMPORTANT

The host plant spectre of a parasite is rarely known exhaustively; this applies in particular at the species level. It is advisable therefore to check at least also the list of all parasites of this genus.

 

mod 23.iii.2019