Farmers Using Fungicide On Corn Need To Apply It Earlier

Farmers Using Fungicide On Corn Need To Apply It Earlier

Waiting until you see the disease present in the field is sometimes too late to spray.

No two growing seasons are the same, as highlighted by the stark contrast of 2012 and 2013. Extreme weather plagued corn growers during both seasons and raised serious yield concerns, but the specific plant stresses of the two years couldn't have been more different.

The word "drought" best summarizes 2012. However, conditions in 2013 were more complex, with wet, cold early-season conditions leading to delayed planting or, in some cases, corn germination issues that led to replanting. Wet weather throughout the spring also heightened the risks of poor root development, diseases and lodging.

PREPARING FOR THE UNKNOWN: The 2013 growing season was different from 2012 and the plant stresses of both years were different. Both summers ended up being quite dry, but first half of 2013 growing season was cooler than normal. It turned extremely hot and continued dry after mid-August and well into September. Growers who applied foliar fungicide later, after tasseling, didn't get as good of a response as growers who made an earlier application, says agronomist Rich Lee.

"We've had a lot of weather stress in my area the last couple of years," says Rich Lee, Syngenta agronomic service representative at Walford in eastern Iowa. "It has been too wet, too cold, too dry and too hot, all in the same year. We can't control the weather, but we can help limit its impact by using the right fungicide."

Waiting until you see foliar disease on corn plants may be too late to spray

Since no one can control the weather or even predict it in the long term, Iowa corn growers can benefit from a careful assessment of their crop management practices, he says. The traditional practice of waiting until R1 stage of corn growth to scout and make a fungicide application decision may not be the best approach.

"We are trying to help growers get ahead of the curve," says Lee. "Instead of waiting until they see a problem, they can count on some of these problems to be perennial. Problems like weather-related stress will be there every year. I think it's time we adjust to that and say, 'I'm going to apply a fungicide because I know to some degree this will be an issue.' In my opinion that's management and that's what puts some folks on top."~~~PAGE_BREAK_HERE~~~

Growers who used a fungicide with stress management benefits in 2012 often reported that their corn handled drought and heat stress with much greater resilience. Reports included less leaf curling in the heat of the day and ears that had greater grain fill.

Some corn growers see benefit from making two foliar fungicide applications

Dave Keffeler, a grower near Remsen in northwest Iowa, planned a two-pass program of Quadris fungicide followed by Quilt Xcel fungicide in 2012 with the goal of controlling early-season diseases and keeping his plants healthier while they set ear size. He reported having one of the greenest fields in his area with visible improvements in stalk quality.

Alan Bennett, a grower at Galva in northwest Iowa, also applied a two-pass program of Quadris and Quilt Xcel in 2012 and reported, "It was pretty amazing because most corn hybrids around here curled to protect themselves, but my corn just didn't need to protect itself as much."

Some people raise the question, can the use of fungicide show a yield response in a situation where the corn isn't getting enough rain? To answer that, university irrigation studies have looked at the use of fungicides to improve a plant's ability to use water more efficiently.

University studies with irrigated corn have shown that fungicides can improve the plant's ability to use water efficiently

In a 2010 study at University of Nebraska, corn acres either received full irrigation to experience no moisture stress or were 60% irrigated. A portion of the corn in both irrigation regimes received treatments of Quilt Xcel, while the other portion received no fungicide treatment. In the fully irrigated plots, Quilt Xcel increased yields by 8 bushels per acre. More impressively, the fungicide helped increase yields by 15 bushels per acre in the 60% irrigated plots, which almost equaled the yield in the fully irrigated untreated plot.~~~PAGE_BREAK_HERE~~~

The study showed that Quilt Xcel helped enhance the corn plants' water-use efficiency, allowing for more crop growth. In addition, the 60% irrigated plot would save the grower the expense of 4.8 inches of water per acre as well as the costs associated with pumping the water.

Similarly, a sprinkler irrigation study conducted at Kansas State University in 2011 showed untreated corn that was fully irrigated produced the same yield (214 bushels per acre) as corn that was treated with Quilt Xcel at both the early (V4 to V8) and R1 growth stages with only 60% irrigation. In contrast, the untreated corn at 60% irrigation only yielded 188 bushels per acre.

Foliar fungicide applications can become more complex in a year like 2013

In 2013, earlier applications of a stress-managing fungicide also helped protect against threats such as poor root development and poor stand establishment. With a late-developing crop, disease pressure became a concern earlier than usual. Diseases emerged during early grain fill on many Iowa farms, increasing their potential to impact yields more than they would if entering a field later in the season.

According to Lee, fungicide applications can become more complex in a year with uneven emergence like 2013. "A lot of fungicides have to be applied with an adjuvant, which really limits their crop safety and application timing options," he says. "A fungicide, such as Quilt Xcel, that can be applied with straight water keeps you from having to worry that you'll damage pollination on a year of uneven tasseling."

Fungicide plans for 2014 should take into account what is safe, effective and offers the greatest range of benefits, he adds. As demonstrated by the 2012 and 2013 growing seasons, there is no way to predict what the coming year will bring, but growers who proactively protect their crops against plant stress can increase their chances for success. Of course, product performance assumes that disease is present.

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