Infected grain can be lightly to severely shrivelled and lighter in weight with individual kernels usually whitish in colour. In decreasing order of susceptibility, fusarium head blight affects durum wheat, Canadian prairie spring wheat, hard red spring wheat, barley, oats, rye and triticale. Yields are reduced by floret failure and poor seed filling. However, a more important factor of this disease is the contamination of the grain by mycotoxins . DON commonly occurs in soft white winter wheat grown in eastern Canada.
Mycotoxins reduce quality and marketability of crops such as malting barley.
These losses outweigh yield losses. This disease may be more severe on semi-dwarf and durum wheats than on hard red spring wheat cultivars. Although all four of the fungi listed above can cause grain damage, only F. graminearum generally produces the problem mycotoxin. F. culmorum may also be an occasional toxin producer in irrigated wheat. Therefore it is important to identify the species of fusarium attacking the grain head.