By Darren Hefty
I looked back at an article I wrote last year, and the facts are still the facts.
Fungicide Facts
- Fungicides are preventative. They must be applied before the disease hits in order to protect the maximum amount of yield.
- Plant health benefits are real. There actually are changes made inside plants after fungicide applications that cause the plants to respond to stresses differently. Even if you don’t have disease issues, a fungicide application can pay solid dividends.
- Coverage is critical. Fungicides do not move well inside the plant and can only protect the plant tissue they come in contact with. If you don’t get spray coverage on the lower leaves, they are unprotected. If a leaf or other part of the plant has yet to emerge, you can’t protect it with a fungicide application.
Keeping those things in mind, here’s a look at each crop and why you may consider a fungicide application this year.
Corn
There are two timings of fungicide application everyone talks about in corn: V4-V7 and VT-R2. I don’t believe the windows are that broad. Here’s how I see it.
V6-V7 – The real sweet spot, especially in the northern Corn Belt, is the V6 to V7 window. V4 is way too early because there aren’t enough leaves exposed and you can only protect the leaves you spray. V8 to pre-tassel is a timing that some of the top farmers in the world are testing, but mixing a surfactant with the fungicide between V8 and pre-tassel is a no-no because we have seen occasional yield damage. Yield gains at V6-V7 vary greatly, but doubling your money or more is totally possible, especially when you consider that most farmers are using half rates of fungicide due to the size of the plant (depending on where you are located in the country).
The most common products used are those with multiple modes of action. Fortix, Priaxor, Trivapro, and Stratego YLD are the most popular and are all excellent products.
We’ll talk about the VT-R2 window later this growing season. Just know that the next key timing for a fungicide on corn is after your corn field is fully tasseled.
Wheat
The crazy thing about wheat is some guys are about to harvest and others just finished with planting. We really see the most benefit at three key timings.
- Herbicide timing – This is very early season, obviously. A half rate of fungicide is usually sufficient. Again, you only protect the leaf tissue you cover with spray.
- Flag leaf – Of the 3 great timings, this one is where the least amount of farmers spray fungicide, but on average, it’s probably the timing that gives the most yield response. You’ll need a full rate of a fungicide, and most commonly we see a dual mode of action product being applied like Stratego, Priaxor, TwinLine, etc.
- Heading – Start treating at this timing when you see 10% to 15% flowering to protect the wheat from late season diseases like rust and head scab (fusarium head blight). At this stage, you can’t use any of the strobilurin fungicides, which rules out Headline, Quadris, Evito, and most of the combos. The triazoles are the go-to products at this stage and include Prosaro, Caramba, and Tebucon (generic Folicur) among others. Prosaro and Caramba are the best for head scab protection. If you are thinking you can’t afford a treatment at this timing, Tebucon is so inexpensive ($2) it’s hard to imagine not getting a return on that investment.
Yes, commodity prices aren’t what they once were. What that says to me on my farm is that I need to grow a lot of bushels to pay for things. Fungicides can provide a lot of protection for not many dollars in crops like corn and wheat. They’ve also been shown on average to provide a good return on investment where a dollar spent brings back two dollars or more. Work with your agronomist and consider your local weather and crop conditions to make the best choices on fungicide products and application timings for your farm.