Tips for Comparing On-Farm Fungicide Trials

The topic of fungicides in soybeans and corn for "potential" plant health and yield benefits continues to be a hot topic and many growers are planning to test various products on their farms this year. If you are contemplating a fungicide application in soybeans and corn, take the following into consideration:

Disease Potential

Conditions in many parts of the province have not been ideal for most foliar diseases in soybeans and corn. Determining disease levels prior to application will help you in assessing your risk.

Hybrids and Varieties Respond Differently

It is important that you know the variety or hybrids strengths and weaknesses. In most cases, a fungicide response to disease is highest when applied to a highly susceptible or moderately susceptible variety or hybrid.

Don't Forget the check Strips and avoid Problem areas

You need at least three check strips. Spread them across the field and make them wider then the combine. If you are splitting a field, keep in mind that differences such as soil type, soil fertility, crop rotation/history, diseases/insects, weed escapes, tree lines (lower yield potential), etc may influence the results. Therefore do not include these in your results since it may lead to improper conclusions.

Revisit the Field

Do Not ignore the field after application. Revisit the field and note if any problems such as those listed above have occurred.

Compare Treated and Untreated Areas for Disease

Scout for corn leaf diseases (northern leaf blight, rust, gray leaf spot, etc) and soybean leaf diseases (downy mildew, Septoria brown spot, frogeye, etc). Determine the amount (incidence - % of plants infected) and the severity (how much damage -1 (low) to 5 (high)) between the treated and untreated strips.

Harvest Many Areas

Do Not compare single strips. It is best to average as many strips as you can from different parts of the field for both the treated and untreated check strips. This will allow you to better compare the treated and untreated areas and avoid complicating the results with other field problems.