In Great Britain and/or Ireland:
Foodplant / internal feeder
larva of Acanthiophilus helianthi feeds within capitulum of Centaurea nigra
Other: sole host/prey
Foodplant / internal feeder
larva of Acinia corniculata feeds within capitulum? of Centaurea nigra
Remarks: Other: uncertain
Foodplant / parasite
sporangium of Bremia lactucae parasitises live leaf of Centaurea nigra
Remarks: season: 9-10
Other: minor host/prey
Foodplant / internal feeder
larva of Chaetorellia jaceae feeds within capitulum of Centaurea nigra
Other: major host/prey
Foodplant / internal feeder
larva of Chaetostomella cylindrica feeds within capitulum of Centaurea nigra
Other: major host/prey
Foodplant / sap sucker
nymph of Eurygaster maura sucks sap of Centaurea nigra
Other: minor host/prey
Foodplant / parasite
Golovinomyces cichoracearum parasitises live Centaurea nigra
Other: major host/prey
Foodplant / saprobe
stalked apothecium of Hymenoscyphus limonium is saprobic on dead, fallen, covered by grass stem of Centaurea nigra
Remarks: season: 10-11
Other: major host/prey
Foodplant / saprobe
immersed pseudothecium of Kalmusia clivensis is saprobic on dead stem of Centaurea nigra
Remarks: season: 5-6
Foodplant / miner
larva of Liriomyza centaureae mines leaf of Centaurea nigra
Other: sole host/prey
Plant / resting place / within
puparium of Melanagromyza dettmeri may be found in stem of Centaurea nigra
Foodplant / saprobe
sessile apothecium of Mollisia coerulans is saprobic on dead stem of Centaurea nigra
Remarks: season: 4-6
Other: minor host/prey
Foodplant / internal feeder
larva of Napomyza hirticornis feeds within stem of Centaurea nigra
Foodplant / sap sucker
adult of Oncotylus viridiflavus sucks sap of capitulum of Centaurea nigra
Foodplant / feeds on
larva of Paroxyna misella feeds on Centaurea nigra
Remarks: Other: uncertain
Foodplant / saprobe
effuse colony of Phragmocephala dematiaceous anamorph of Phragmocephala elliptica is saprobic on dead stem of Centaurea nigra
Remarks: season: 4-10
Plant / resting place / within
puparium of Phytomyza autumnalis may be found in leaf-mine of Centaurea nigra
Foodplant / parasite
mostly hypophyllous uredium of Puccinia calcitrapae parasitises live leaf of Centaurea nigra
Other: major host/prey
Foodplant / parasite
pycnium of Puccinia dioicae var. arenariicola parasitises live Centaurea nigra
Foodplant / parasite
uredium of Puccinia hieracii var. hieracii parasitises live leaf of Centaurea nigra
Other: minor host/prey
Foodplant / saprobe
erumpent apothecium of Pyrenopeziza adenostylidis is saprobic on dead stem of Centaurea nigra
Remarks: season: 5-11
Foodplant / spot causer
usually hypophyllous colony of Ramularia anamorph of Ramularia triboutiana causes spots on live leaf of Centaurea nigra
Foodplant / saprobe
gregarious, black pycnidium of Rhabdospora coelomycetous anamorph of Rhabdospora coriacea is saprobic on dead, silvery-grey-spotted stem of Centaurea nigra
Foodplant / shot hole causer
punctiform pycnidium of Septoria coelomycetous anamorph of Septoria centaureae causes shot holes on fading leaf of Centaurea nigra
Remarks: season: 8-9
Foodplant / saprobe
colony of Stachybotrys dematiaceous anamorph of Stachybotrys dichroa is saprobic on dead stem of Centaurea nigra
Remarks: season: 4-9
Foodplant / saprobe
fruitbody of Subulicystidium longisporum is saprobic on dead, decayed stem of Centaurea nigra
Other: minor host/prey
Foodplant / saprobe
sessile apothecium of Unguicularia incarnatina is saprobic on dead stem of Centaurea nigra
Remarks: season: 4-7
Foodplant / gall
larva of Urophora jaceana causes gall of receptacle of Centaurea nigra
Remarks: season: -9
Other: major host/prey
Foodplant / gall
larva of Urophora quadrifasciata causes gall of capitulum of Centaurea nigra
Other: major host/prey
Foodplant / internal feeder
larva of Xyphosia miliaria feeds within capitulum of Centaurea nigra
Other: unusual host/prey