Over the past several years the prevalence of the 3-A DON chemotype, which produces more of the mycotoxin deoxynivalenol, or DON, has been increasing.

Dr. Anita Brûlé-Babel, a wheat breeder with the University of Manitoba, says although yield is affected by fusarium head blight, the larger concern is its effect on the acceptability of the grain.

Dr. Anita Brûlé-Babel-University of Manitoba

It's definitely a concern especially when we're looking at our international markets and trying to make sure that our grain is accepted on international markets.

We don't want to be in a situation where we have higher levels of toxicity than are acceptable when you're marketing the grain internationally so we do have some concern in terms of making sure that we can produce product that is acceptable on the international markets.

One of the problems that we're seeing, at least with some of our research and especially with these new forms of fusarium graminearum, is that our grading system really primarily deals with fusarium damaged kernels in a grain sample and bases their levels of fusarium or predicts their toxicity levels of the toxin based on that.

What we're seeing with our results is that the relationship between fusarium damaged kernels and actual toxin levels with these new forms is not as well correlated so we're finding that that can be a concern from the grading system point of view and I suspect that in the longer term we're probably going to have to see actual measurements of the toxin as part of our grading or our longer term strategy in terms of ensuring that we can deliver grain that meets international standards for toxin levels.

Dr. Brûlé-Babel says, while plant breeders are making progress in improving wheat's resistance to fusarium head blight, this is a difficult disease to work with so progress has not come quickly.