V5 fungicide applications to corn

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.

FUNGICIDE DIFFERENCES
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.”