Scouting Small Grains: A First Line of Defense for Organic Growers

For organic grain growers, combating plant disease is especially challenging because there isn't much organic-specific information available. Since organic farmers can't use conventional fungicides, they rely on cultural practices and variety choices to keep disease in check. The first step is finding out which diseases are in the field and which varieties can stand up to them. The OROWS organic small grains project at Penn State is providing an important opportunity for side-by-side plant disease comparisons in organic grains. 

Dr. Adriana Murillo-Williams, who leads the disease assessments for the project, has a background in plant pathology and studies how diseases emerge across different small grain varieties and how cultural practices affect them. "Pennsylvania organic farmers need more reliable information about small grain disease susceptibility," Murillo-Williams said.  

The whole process starts with scouting. The first step in any integrated pest management program is simply identifying the disease and the organism causing it. Knowing the pathogen tells a grower where the trouble is coming from, whether it's blowing in from a neighboring field, or surviving in last year's crop residue, and whether a practice like changing the crop rotation could even help. From there, a grower should assess the severity of the disease and whether their chosen varieties are optimal. A resistant variety fends off infection while a tolerant one may still get infected but recovers and yields well anyway.  

Grain diseases deserve the same attention as the ones you can see on the leaves. Fusarium head blight, or head scab, is one of the most important. It lowers yield and test weight and leaves behind small, shriveled kernels that can carry mycotoxins like deoxynivalenol (DON), which can get a load of grain docked or rejected if present above a certain threshold. A grower who knows the grain is affected can adjust the combine fan to blow those lightweight kernels out the back, clearing out much of the toxin. This is a simple harvest adjustment that applies across wheat, barley, oats, and rye. 

By tracking how varieties respond to disease under different cultural practices, Murillo-Williams is working to answer the questions she receives from organic growers: which varieties are truly resistant and which are tolerant; whether varieties differ in disease severity; and how cultural practices change that picture. As results build season after season, the project is steadily closing an information gap that organic growers have faced for years. For farmers working with limited disease-management information, that variety-by-variety data is a practical tool they can put to work, starting with a walk through their own fields. Preliminary results from the OROWS project should be out in early 2027. For ways to improve your accuracy in scouting, check out the Crop Protection Network's Field Crop Disease and Insect Loss Calculator.