Foodplant / miner
solitary larva of Agromyza rondensis mines leaf of Hordeum vulgare sens. lat.

Foodplant / spot causer
erumpent pycnidium of Ascochyta coelomycetous anamorph of Ascochyta hordei causes spots on live leaf of Hordeum vulgare sens. lat.

Foodplant / spot causer
pycnidium of Ascochyta coelomycetous anamorph of Ascochyta hordeicola causes spots on leaf of Hordeum vulgare sens. lat.

In Great Britain and/or Ireland:
Foodplant / parasite
Blumeria graminis parasitises live Hordeum vulgare sens. lat.

Foodplant / pathogen
erumpent Ascochyta coelomycetous anamorph of Didymella exitialis infects and damages leaf of Hordeum vulgare sens. lat.
Remarks: season: 3-8

Foodplant / parasite
uredium of Puccinia graminis f.sp. secalis parasitises live stem of Hordeum vulgare sens. lat.

Foodplant / parasite
telium of Puccinia hordei parasitises live stem of Hordeum vulgare sens. lat.
Other: minor host/prey

Foodplant / spot causer
linear, long covered by epidermis telium of Puccinia striiformis var. striiformis causes spots on live stem of Hordeum vulgare sens. lat.

Foodplant / pathogen
live leaf of Pyrenophora graminea infects and damages Drechslera dematiaceous anamorph of Hordeum vulgare sens. lat.

Foodplant / spot causer
immersed pycnidium of Septoria coelomycetous anamorph of Septoria passerinii causes spots on live leaf of Hordeum vulgare sens. lat.

Foodplant / internal feeder
larva of Trachelus tabidus feeds within stem of Hordeum vulgare sens. lat.
Other: major host/prey

Foodplant / pathogen
embedded sorus of Ustilago hordei infects and damages live spikelet of Hordeum vulgare sens. lat.

Foodplant / pathogen
exposed sorus of Ustilago tritici infects and damages live spikelet of Hordeum vulgare sens. lat.