Fusarium graminearum Schwabe 1839
Fusarium head blight
Triticum aestivum, Hungary, Kimle, 27.vi.2016 © László Érsek: the pale sections of the ears are diseased
The fine orange lines, mainly over the veins, are sporodochia, where conidia are formed
two orange sporodochia
microphoto of a sporodochium with conidia (photo derived from Wikipedia)
The fungus infects the young ears and from there invades the complete plant body. Infected fruits become malformed and are aborted. Mainly on the ribs of the spikelets orange sporodochia develop: mats of hyphae and conidiophores were sickle-shaped conidia are formed that cause multiple reinfections. Later in the year pycnidia are formed on the plant and, after the harvest, on the remaining stubbles. This is the teleomorph, where along a sexual process ascospores are formed the infect the plants in the following spring.
The fungus not only causes much damage by a severe crop loss, but also produces some highly active mycotoxines that may make the the grass dangerous to eat for cattle.
Poaceae, broadly oligophagous
The teleomorph is known as Gibberella zeae (Schweinitz) Petch, 1936. According to the Index Fungorum (2018) Fusarium graminearum is the valid name.
Brandenburger (1985a: 847), Ellis & Ellis (1997a), Ruszkiewicz-Michalska (2006a), Schmale III & Bergstrom (2018a), Trail (2009a).