Wheat foliar diseases surfacing
By David G. Hallauer
Meadowlark Extension District Agent
It may not be a concern on your radar right now, but wheat foliar diseases have already begun to surface in the South.
Maybe it won’t become an issue for us— maybe it will, but with leaf and stripe rust present in Texas and affecting varieties like Everest and Armour, it’s at the very least time to start thinking about what your options for disease control may be.
Does that mean you are going to have to spray? Absolutely not. What it does mean is you need to understand your wheat crop. What diseases am I looking for (leaf and stripe rust are the big ones)? What stage is the crop in, and by what time do I need to be applying a fungicide if I so choose (full flag leaf emergence to flowering)?
You should check to see what your variety’s natural resistance level might be as well. K-State research indicates that achieving a greater than 4-bushel-per-acre yield response to a foliar fungicide is only likely 15 percent of the time for a variety with resistance—but slightly greater than 40 percent of the time for a susceptible variety. If you start to factor in the level of disease risk, those numbers can easily jump quite a bit—either way.
To help you sort through the mass of considerations that have to be made, I want to make you aware of three decision making aids. Evaluating the Need for Wheat Foliar Fungicides helps you evaluate what diseases you are seeing while referencing some of the trials I noted above. It’s a great reference as a “one stop shop” to helping you start the decision making process. Once you determine you need to apply a fungicide, check out Foliar Fungicide Efficacy Ratings for Wheat Disease Management 2013. It helps you sort through which product is what – and what it will do. And if you want to take a more “calculated” approach, there is a spreadsheet on the economics of spraying field crops that you can download from www.agmanager.info.
Let’s hope disease pressure stays low and yields are high, but if not, these resources can be a great help as you make your decision to spray or not to spray.