As we plan for the 2010-2011 wheat season, let us take a quick look back and learn from this past crop. Ohio had everything this year – head scab and vomitoxin, Stagonospora leaf and glume blotch, powdery mildew, leaf rust, head smut, cereal leaf beetle, plus a very hot late-spring-early-summer. The big problem this year was head scab and vomitoxin, with incidence ranging from 3 to 60 percent and vomitoxin from less than 1 to 18 ppm. Both Stagonospora and powdery mildew were also very severe depending on the field, with a severity score of 7 out of 10 this year. Diseases combined with a short grain fill period resulted in low to moderate yield and grain quality, with average yield ranging from 40 to 90 bushels per acre and reported test weights from 45 to 61 pounds per bushel.

Dr. Pierce Paul, Ohio State University Extension plant pathologist, has stated that rarely did we see all of the disease problems in the same fields.  As is usually the case, some fields still escaped most of these problems. This is largely because those fields were either planted with resistant varieties, in a good rotation, treated with a fungicide at the right time, flowered before or after it rained, or various combinations of the above. Even in areas where the scab levels were high, some of the fields with the lowest levels of vomitoxin, highest yields and test weights were those that received a fungicide application at flowering. However, vomitoxin levels were still higher than 3 ppm in some of the treated fields. Similarly, fields treated for Stagonospora also had better grain yield and quality than fields left untreated. Combining variety resistance with fungicides added a few more bushels to yield and pounds to test weight. Positive this season is the fact that the scab forecasting system did a good job of alerting us about the risk of scab.

Planning for next year, remember that we will almost always get some powdery mildew; if it is wet and humid during the early and middle portions of the season, we will certainly see Stagonospora and Septoria leaf blotch; if it is wet and humid during flowering we will more than likely see head scab. The scab forecasting system will help us to detect this risk early, and generally when there is a high risk for scab, Stagonospora glume blotch tends to be high also. Foliar diseases can be managed effectively with resistance or with a well-timed fungicide application if the variety is susceptible, with a percent control as high as 90 percent. Resistance must be combined with a fungicide application at flowering to achieve the best results in terms of scab and vomitoxin control. It is almost impossible to find a variety that is resistant to scab, Stagonospora, powdery mildew, and rust, and still yield well. Maybe that priority should be given to scab resistance. If you cannot find a variety that is resistant to multiple diseases, be prepared to use a fungicide to manage other diseases, if the weather conditions become favorable. In fact, planting resistant varieties with different flowering dates (maturity) will almost certainly reduce the chance of your entire field being affected by a disease, even if the weather becomes favorable.

Disease management needs to be one of the top things on our list if we are going to have a great wheat crop. In any given season, if the weather conditions are favorable, diseases can take a bite out of both yield and quality of even our highest-yielding varieties. Let us start by choosing resistant varieties, especially to head scab, as we plan for our next wheat crop.

The views and opinions expressed in this column are those of the author and not necessarily those of Farm World. Readers with questions or comments for Roger Bender may write to him in care of this publication.