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Causal organism - Fusarium
spp.
Primarily: F. avenaceum, F. culmorum, F. graminearum,
Microdochium nivale, F. poae
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Of the 14 or so species of Fusarium which have been isolated from wheat crops in the UK, only F.culmorum, M.nivale, F.avenaceum and F.graminearum can be regarded as aggressive pathogens - F.culmorum and M.nivale being by far the most common. A fifth species, F.poa, though it seldom causes more than small lesions on the glumes is potentially serious as one of those species capable of producing poisonous mycotoxins .
The most common symptom of a serious attack of Fusarium is very poor plant establishment, i.e a very thin crop. This occurs because of pre-emergence and post-emergence seedling blights - the most important phase of the disease. Root rotting, brown foot rot and leaf blotching (usually following some other form of damage), glume blotch and ear blights can all be caused by these fungi. Severe foot rot, usually affecting plants under stress (especially moisture stress) can result in premature ripening and 'whiteheads'. Under prolonged snow cover M.nivale can cause 'snow mould'.
