Adults are about 3.4–4.5 mm long.
Fine-art photographic collection
Opomyza germinationis
A tiny spotted-wing fly whose larva spends winter hidden inside a grass shoot and can kill the shoot from the centre outward.
About this species
Opomyza germinationis(Linnaeus, 1758)
Information reviewed15 July 2026
Opomyza germinationis is a European grass fly. Adults are small orange-brown flies with patterned wings; larvae are internal stem feeders in grasses, including pasture and cereal relatives.
Taxonomy
Animalia · Arthropoda · Insecta · Diptera · Opomyza
Accepted taxon. · checked 2026-07-15
Europe and parts of temperate western AsiaBroad range and selected reference localities — not a complete occurrence map.
Europe and parts of temperate western Asia
Grassland, field margins, hedgerows and cereal-growing landscapes.
Adults emerge in summer, disperse, then return to grassland to mate and lay eggs in autumn.
Larvae feed inside grass shoots; adults take surface liquids.
Solitary.
What makes this species remarkable?
The larva passes the cold season as a third instar concealed in the basal part of a grass tiller, turning a hollow plant shoot into both shelter and food store.
Feeding destroys the central growth point and produces a “dead heart”: the outer leaves may remain standing while the youngest central shoot can be pulled out dead.
Adults can live for months after their early-summer emergence, leaving fields for hedges and woodland before returning in autumn to place the next generation into grass.