organ parasitic mode stage note taxonomic group parasite
flower borer Alucitidae Alucita huebneri
flower down Peronosporales Peronospora violacea
flower gall Microbotryales Microbotryum intermedium
leaf bud gall Eriophyidae Aceria squalida
leaf down Erysiphales Erysiphe knautiae
leaf down Erysiphales Leveillula taurica
leaf down Erysiphales Podosphaera dipsacacearum
leaf down Peronosporales Peronospora knautiae
leaf miner Agromyzidae Chromatomyia scabiosae
leaf miner Agromyzidae Chromatomyia scabiosella
leaf miner Gracillariidae Phyllonorycter scabiosella
stem gall Alucitidae Alucita grammodactyla
stem gall Asterolecaniidae Planchonia arabidis
flower vagrant spring generation Aphididae Aphis confusa
leaf vagrant summer generation Aphididae Aphis confusa
root collar vagrant Aphididae Aphis thomasi
stem vagrant summer generation Aphididae Macrosiphum rosae


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.


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.


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 22.vii.2018