Plant Health Involves More Than Meets the Eye

In 2020, Seven Springs Farms in Cadiz, Kentucky, had a cluster of four farms that shared fence rows and should have had comparable yields. But, they didn’t.

One farm wasn’t treated with a fungicide because it included a seed grower’s test plot. The treated farms averaged 231, 226 and 228 bushels per acre (bu/A). The untreated farm averaged 205 bu/A.

“Needless to say, we aren’t skipping fungicide applications for test plots anymore,” says Nick Woodruff, technology manager at Seven Springs Farms.

Corn Growers See Fungicide Benefits

Crops undergo a constant struggle to maximize genetic potential in the face of root, stalk and foliar diseases, as well as stressful environmental conditions. Perpetually reacting to both biotic and abiotic stressors, plants constantly fight to achieve optimal performance. Fungicides are a key tool growers use to mitigate damage from stress and diseases that can negatively impact their bottom line. But certain fungicides, such as strobilurins and Adepidyn^® technology, which are ingredients in Miravis^® Neo fungicide, or Solatenol^® technology, an ingredient in Trivapro^® fungicide, can also provide plant health benefits lasting into harvest and driving up yield potential. As such, row crop growers are rethinking the way they incorporate fungicides into their input decisions.

“The decision to invest in crop inputs is typically driven by the grower’s desire to maximize yields,” says Tyler Harp, technical product lead at Syngenta. “The 2021 season saw favorable gains in commodity prices, which helped underscore the value of fungicide applications to increase yield. And, although most corn acres remain untreated, treated acreage has steadily increased over the last 20 years as growers continue to realize the value and benefits of fungicide use on corn as well as other row crops, regardless of the current commodity prices.” Currently, about 20 million acres of corn are treated with a fungicide, up from under 1 million in the late 1990s.

Controlling Southern Rust

Seven Springs Farms incorporates fungicides into its annual business plan. Established in 1994 by Joe Nichols, managing partner and 2010 Kentucky Farmer of the Year, Seven Springs Farms now encompasses nearly 30,000 acres across multiple counties in western Kentucky. The operation consists of row crops, cattle, tobacco, excavating and straw blanket production.

Southern rust has been an agronomic challenge at Seven Springs Farms for several years. The disease robs corn of nutrients and affects plants’ ability to manage water loss, which can lead to increased lodging and reduced yields. To manage Southern rust, the operation applies Trivapro, which they’ve found provides the best control. However, it isn’t just the threat of Southern rust that drives input decisions at this farm.

“Our decision to apply corn fungicide is now based more on yield potential than on disease pressure,” Woodruff says. “We’ve seen improvements of 20+ bu/A on check strips from yield benefits alone.”

In some parts of the U.S., disease epidemics can be destructive, and fungicide applications are driven by consistently high pressure. In other locations, disease pressure varies year to year.

“A well-placed fungicide application that provides plant health benefits still protects crops from potential disease outbreaks,” Harp says, “while also increasing the efficiency of the crop and management of abiotic stresses, or environmental pressure like hail or windstorms.”

In recent years, Seven Springs Farms had light disease pressure at the time they made their application decisions. “We’ve done some checks in the past where we have shown 20+ bu/A increases in light disease years,” Woodruff says. “If we have a farm that we expect to have a high yield potential, we are going to spray it with fungicide, regardless of disease pressure.”

Increase Crop Resilience

Beyond disease control and easing stress, the physiological plant health benefits of fungicides include prolonged duration of green leaf tissue, improved water and nutrient-use efficiency, and enhanced energy (photosynthetic) efficiency.

“The physiological effects on crops increase overall efficiency of energy production and water use, which allows the crop to better withstand abiotic stresses — such as drought, humidity and extreme temperatures — along with biotic stresses from diseases and insect pressure,” Harp says. Syngenta fungicides, such as Miravis Neo and Trivapro, typically provide a delayed senescence and/or extended green leaf duration leading up to harvest, ensuring maximum late-season grain fill and higher yields.

The symbiotic relationship between healthier plants and higher yields starts with ensuring crops are cleaner and greener, Harp says, meaning diseases are under control and the plant’s overall health is maintained. Greener leaves allow plants to capture more light. That light, referred to as “photochemistry” in the plant, is important for optimal energy production and allows for higher yields. Greener plants also hold more water, ensuring better conservation and efficient use of water and nutrients. In corn, plant health fungicides promote a healthier and thicker stalk, increasing harvest efficiency and potentially contributing to higher yields.

Three Factors for Higher Yield Potential

“All three of these factors — more light capture, better conservation of water and nutrients, and superior harvest efficiency — contribute significantly to a healthier crop and higher yields,” Harp says.

Woodruff recognizes how fungicides help improve plant health in addition to boosting yield potential, and he specifically likes the standability late in the fall because it holds crops up better for harvest.

“Across 56 locations in the Corn Belt from 2018 to 2020, including many with little or no disease severity reported, Miravis Neo provided just over 15 bu/A on average increase in yield over the untreated across all locations,”1 Harp adds. “In soybeans, we have found yield increases of ~6 to 9 bu/A over untreated in fields previously scouted and reported as not requiring a fungicide  application.”¹

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¹“See the Difference in Corn with Miravis Neo.” 2020 Corn Fungicide Trials – Miravis Neo | Syngenta US, Syngenta, syngenta-us.com/p/boost-your-bushels/trials/corn/neo/index.html. Assuming representative of average user experience and supported by reproducible data.