By Nathan Kleczewski
“Should I apply a fungicide to my wheat?” That is a common question among many growers this season. My advise has been this: go out and look at your wheat. Really look at it, don’t just drive by at 60 mph with Lynyrd Skynyrd blaring on your radio. Here is what to look for:
- Presence of active foliar disease in the mid to upper canopy. The name of the game now is protecting the flag leaf and then the glumes, which contribute the lions share of carbohydrates for grain fill. Diseases such as powdery mildew tend to stay low in the canopy due to humidity and temperature constraints. Diseases such as leaf blotch complex move slowly and often make it to the flag leaf after flower. Rusts, for the most part come in late, after flower, if at all. However, see my recent post on stripe rust.Most of the fields we have been in for survey purposes and applied research trials have been largely free of disease.
- Yield potential– are you looking at a field with excellent yield potential? Paying for an application is much easier when you are pushing 100 bu/A vs 60 bu/A.
- Costs of inputs up to this point, and disease pressure compared to your projected yield.
If you don’t look at your field or pay someone to do it, you could potentially apply fungicides to low disease potential, low yielding fields. If you cannot make it out to check your fields, consider a reputable scout or scouting service.
With wheat prices hovering around $4.40 /bu, margins will be tight. This is why it is important to consider the amount of disease loss you are protecting by making a fungicide application. How much will you have to make back? Check out the breakeven sheet here wheat breakever2016.
The calculator provides you with average costs of products and application costs for the various application timings in the mid-Atlantic. The application cost of the greenup/jointing application only considers product ($US / A) as you will typically be going across the field at this time anyways to apply your second shot of nitrogen. You can see that at $4.00-4.50 most applications will need to protect roughly 6 bu / A to break even over 10 bu/A are required for programs using a flag leaf application plus a flowering application or a three-spray program. That’s a pretty good slug of disease.
You have your own deals and discounts, so to see what you’d need to break even, enter in your application costs in the table on the right (greenup, flag leaf, or flowering). The calculator will do the rest. Do you have enough disease and yield potential to justify the application?
That’s one piece of the puzzle. The next is the likelihood of a return. Thankfully, we are doing some excellent work answering this question (led by M.S candidate and Kent County Ag. Agent Phillip Sylvester). Phillip’s work will lay the ground work to begin to develop a small grains calculator that will provide growers with estimated probabilities of an application paying off over a range of yield potentials given the application cost and commodity price.