Disease is one of the major factors limiting yield of wheat in Ohio and other Midwestern states. In the humid Midwest, losses as high as 30 to 50 percent are common where disease control has not been practiced. Fortunately, most grain producers use sound disease-control practices. The use of modern high-yielding varieties, crop rotation, proper planting date, and balanced fertility are well accepted agronomic practices that significantly limit the extent of yield losses due to disease.
Diseases do not just happen — they are the result of the combined action of three distinct factors. Diseases occur when a pathogen attacks a susceptible plant under environmental conditions that favor the infection process. Different environmental conditions favor different types of diseases. For example, some require a water film on leaf surfaces while others are inhibited by the presence of water. In any case, diseases require specific conditions before they become an economic problem.
Effective disease management requires knowledge of the important yield-limiting diseases most likely to occur in the area. Producers facing specific disease problems can fine-tune their disease-control strategies to those few diseases encountered each year. Correct diagnosis of the disease problem is the cornerstone to effective control. Producers with little experience identifying diseases should seek help from competent sources, such as agricultural universities, Extension, or private consulting services. Good photographs and detailed information about specific diseases can be found on Ohioline at http://ohioline.osu.edu and the Ohio field crop disease web site at www.oardc.ohio-state.edu/ohiofieldcropdisease.
In designing a disease-management system, it is important to consider all the different strategies to reduce the level of disease. This integrated approach to disease control is based on the knowledge of the life cycle of the pathogen and how disease develops. It provides added protection, usually at minimal cost.
Integrated disease-management systems incorporate as many disease-control strategies as possible. Disease-resistant varieties, crop rotation, and tillage are especially important in management of wheat diseases. Factors such as balanced fertility and soil pH, planting date and rate, and seed treatments are also important and in some cases foliar fungicides may be used to stop serious disease development.
Important web sites for wheat disease information:
Ohioline at http://ohioline.osu.edu
Ohio Field Crop Disease at www.oardc.ohio-state.edu/ohiofieldcropdisease