Experience in Denmark with Cereal Cultivars Resistant to Cereal Cyst Nematode (Heterodera avenae Woll.)1)

On the basis of investigations on the cereal cyst nematode's distribution, it is presumed that one third of all the cereal growing areas in Denmark is infested to a degree, and that yield losses of 5 % or more may be assumed. This means an annual loss of about 100 million D.Kr. By using resistant cultivars every second year, the population of Heterodera avenae Woll. can be kept at a harmless level. It may be assumed that intensive growing of nematode-resistant cereals includes a risk of promoting the occurrence of pathotypes other than the 2 known to exist in Denmark. So far, there is no indication for their existence.