Fusarium head blight (FHB) of small cereals is a disease of global importance 
with regard to economic losses and mycotoxin contamination harmful to human and 
animal health. In Germany, FHB is predominantly associated with wheat and F. 
graminearum is recognised as the major causal agent of the disease, but little 
is known about FHB of barley. Monitoring of the natural occurrence of FHB on 
Bavarian barley revealed differences for individual Fusarium spp. in incidence 
and severity of grain infection between years and between spring and winter 
barley. Parallel measurement of fungal DNA content in grain and mycotoxin 
content suggested the importance of F. graminearum in winter barley and of F. 
langsethiae in spring barley for FHB. The infection success of these two species 
was associated with certain weather conditions and barley flowering time. 
Inoculation experiments in the field revealed different effects of five Fusarium 
spp. on symptom formation, grain yield and mycotoxin production. A significant 
association between fungal infection of grain and mycotoxin content was observed 
following natural or artificial infection with the type B trichothecene producer 
F. culmorum, but not with the type A trichothecene-producing species F. 
langsethiae and F. sporotrichioides. Trichothecene type A toxin contamination 
also occurred in the absence of significant damage to grain and did not 
necessarily promote fungal colonisation.