V5 fungicide applications to corn
The benefit has been verified that a fungicide application near V5 stage of field corn growth can result in yield benefit in most situations. Of course, the amount of benefit varies based on the weather and the production practices of the individual corn grower.
Technical and field trial investigation of applying a fungicide at the V5 stage of growth really increased starting in 2008, according to the fungicide manufacturers selling the most product in the corn market.
BASF, the company that led the charge in fungicide application to corn with Headline fungicide, notes investigation of application timing at all stages of corn growth began in 2003. “What we have seen historically and what we have continued to see is that the early timing of V5 or V6 vegetative growth stage fungicide applications have on average, across the board, resulted in yield response in the five-to-seven bushels range,” said Nick Fassler, BASF, technical marketing manager, fungicides.
Last year, Syngenta and Bayer CropScience worked with a large number of corn growers to verify their products’ abilities to help corn reach its yield potential by protecting the corn plant from early-season diseases.
Bayer CropScience conducted trials with its new Stratego YLD and saw farmer-field yield advantages greater than non-treated acres for a V3 to V6 application averaging 8.3 bushels per acre.
The largest number of field trials in 2010 was conducted by Syngenta with a Quadris application between V4 and V8. Variation in application timing can be accounted for by Syngenta relying on farmer cooperator application in 166 total fungicide trials, not all of them limited to early-season timing. Of those trials with an early-season application, the overall national average was about six bushels per acre positive yield response.
The intense interest in fungicide use on corn in 2010 also confirmed that the standard corn fungicide application for the most yield advantage is still at the tassel stage of corn.
“Most of the earliest research work was done around VT to R1, and in fact, that is still where we see the greatest yield benefit. But we have determined that by going early growers can also recognize additional yield benefit, albeit not as high as we typically see with a later application,” said Eric Tedford, Syngenta, fungicide technical brand manager.
Tedford provided examples of the variation in yield advantages using an approximate V5 application plus a R1 application. Minnesota trials of Quadris early followed by Quilt Xcel at R1 showed a 32.1 bushel average yield advantage compared to non-treated corn in 34 trials. Illinois trials
for the same applications in 27 fields showed a 16.6 bushel average increase.
On a national basis, Bayer CropScience calculated an average 15.2 bushels per acre advantage when using Stratego YLD no later than V6 and again at R1. BASF reports its years of data show a range of a 16 to 20 bushel per acre yield improvement for an early-season plus R1 sequential application of Headline compared against non-treated check fields.
The difference in national average yield per company can be explained to a degree by where the trials were conducted and the overall agronomics used to grow the corn in trial fields.
“We are seeing the greatest from V5 fungicide applications in corn-on-corn production practices. We see much higher disease pressure in these fields; so, it is critical to keep the young corn plants healthy and disease free during the ear development stage between V3-V6. Anthracnose leaf blight can infect the plants during this time, which leads to stalk quality issues later in the season. Disease in general also flourishes more in high-population plantings and narrow-row production, said Ethan Luth, Bayer CropScience, crop marketing coordinator.
“The early application is additive with a late-season application; it is a nice addition for guys that are really driving yield potential, but that application is our second recommendation after a tassel application,” said Fassler.
EASY TO SELL
Luth said that growers this year should be willing to listen to an agronomist’s suggestion about using a V5 application. Growers seem ready to buy into an anthracnose-control application, possibly even more than paying for an R1 application every year.
“The late-year application occurs when growers are worried about their crop being worth the money to control gray leaf spot and late-season diseases,” he said. “They look at the commodity prices and worry if the application will pay for itself.”
A V5 application can also be sold as an addition to a glyphosate herbicide application. The timing is right for a post-emergence tank mix application of glyphosate, a second mode-of-action herbicide and the fungicide. The fungicide can ride along in the tank and not cost the grower anything more than the product.
This year shouldn’t be a hard year to convince corn growers to spend money on fungicide applications. For the sake of an example, we can use the number five as the wild card in calculations. A minimal yield improvement from a V5 application of five bushels per acre, a sequential application program yield improvement of 15 bushels per acre and $5 per bushel corn price results in $25 per acre or $75 per acre added grower income. The fungicide cost and application fee is not going to eat up much of that extra income.
BENEFITS NOT ALWAYS OBVIOUS
Tedford said, “We don’t always see early-season disease in corn, but particularly last year the weather was crazy enough that there was a fair amount of disease such as anthracnose and some of the diseases that come in early.” He explained that Syngenta’s research indicates it isn’t completely disease control but also beneficial effects on some key plant physiological processes that help keep corn plants strong and healthy. BASF and Bayer agree.
Non-direct income benefits from protecting the corn plant early and late can show up in easier harvesting. Diseases and plant stresses can result in lodged corn. Tedford said improved harvest efficiencies can be calculated as money saved or earned.
Tedford reported the harvest results of a research project between fungicide-treated and untreated fields. “In the treated plot, there was just about 2 percent lodging, and in the untreated plot, there was close to 25 percent lodging. The combine could go through the treated field 1.7 miles per hour faster because corn wasn’t down. That might not sound too impressive, but if you put it into economic models, it comes out to about a $10 per acre increase in money to a grower in harvest efficiency from gas, time, etc.,” he said.
Different active ingredients and formulations of fungicides are being offered by the biggest crop protection pesticide manufacturers and many smaller companies. The fungicides come from two classes of chemistry — strobilurins and triazoles.
Strobilurin fungicides have been the most common class of chemistry for use in corn — the market leaders have been Headline, Quadris and Stratego. Several companies also are selling strobilurin family products with their own benefits. Evito is an example from Arysta LifeScience that the company touts as being rainfast quicker than other products and formulated at an extremely low use rate.
The combination of a triazole and a strobilurin have been registered for use in the last two years — examples being Headline AMP, Quilt Xcel and Stratego YLD.
The strobilurins are preventive fungicides (kills spores before they germinate or just after but before the fungus penetrates the plant tissue), and the triazoles have a curative effect (stop the activity of fungus after it has infected the plant and is already utilizing the plant’s nutrients).
The combination fungicides work in tandem, but it is the strobilurins that do more than prevent infection. They provide physiological benefits that in one way or another are referred to as plant performance, explained Tedford. Physiological benefits include overall plant health and are usually seen as plants staying greener longer, stalks not lodging and ears filling out.
Tedford said, “The result is that plants are better able to reach their full genetic yield potential.”
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