February 01, 2023

The science behind ‘greener and cleaner’ for plant health

NEW ORLEANS — Root, stalk and foliar diseases, as well as stressful environmental conditions, are among the constant threats to yield potential — and going “cleaner and greener” can provide the protection needed.

“We know that with some of the diseases we have today such as tar spot and other diseases it can contribute to maybe 60% loss of corn yield in some cases,” said Tyler Harp, Syngenta insecticide/fungicide technical product lead.

“In 2022, rain and supply chain issues caused delays in planting corn and soybeans. This made plants more vulnerable to diseases during the early growth stages and throughout the season. In addition, much of the U.S. saw extreme heat stress during the summer, again making crops more susceptible to abiotic stress.”

How can growers better manage these issues and preserve their yield potential?

Harp: It’s all about protecting yield and harvestability on two fronts — cleaner and greener. Cleaner, because it’s free of yield-robbing diseases with a fungicide, and greener, because it’s a more robust, healthier crop that makes it more able to withstand abiotic stresses like heat and drought.

So, I’m talking about plant health benefits that provide healthier and more productive crop. When using a Syngenta plant health fungicide such as our Miravis brands, you often see a prolonged greening effect in the field.

Even in fields with low disease pressure, plant health benefits, like greening, can translate to higher yield potential in corn and soybeans. There’s the abiotic stress management component that’s continuing to preserve yield.

What have fungicide trials revealed?

Harp: In test plot results in 2020 in a field with less than 5% disease severity, non-treated soybeans averaged 68.9 bushels per acre and the soybeans treated with Miravis Top fungicide averaged 81.2 bushels per acres.

Oftentimes, the results are really significant yield increases and can add value to the grower and the return on investment could be quite significant.

We know that products like Miravis and Trivapro are preserving yield, not only by disease control, but also through the management of abiotic stresses — heat and drought.

What are the advantages of “greener” plants?

Harp: Greener means healthier, more efficient and productive crops and greener leaves provide more light with more light energy. Greener also means higher water and nutrient-use efficiency.

Additionally, greener provides harvest efficiency and quality. It means healthier and higher quality crops and healthier crops provide a more profitable harvest.

All three of these concepts together, working in parallel from the use of a Syngenta plant health fungicide, allow a grower to achieve maximum yields.

What is the science behind “greener and cleaner?”

Harp: Capturing more light energy through greener leaves. We’ve done some studies in the laboratory that clearly show that when Adepidyn technology, which is one of the components of our Miravis brand, is applied on soybeans in simulated drought conditions the plants are better able to manage those conditions and continue to have more photochemistry in the leaves.

Photochemistry is the light energy in the leaf that comes from sunlight that allows that leaf to continue to produce more energy. So, in the presence of stress the leaves have a more efficient use of energy because of the Adepidyn technology plant health fungicide.

Greener plants use water more efficiently. Plant health benefits from Adepidyn technology helps plants better conserve water by reducing the transpiration rate while maintaining high levels photosynthesis.

Do healthier crops have an impact on efficiency and harvest?

Harp: Yes, when we compared treated and untreated crops, we know that those treated corn plants have a healthier stalk. When you have a lot of disease and a lot of abiotic stress, the leaves will pull starches out of the stalk and compromise the integrity of that stalk.

So, not only are we getting more yields in our treated plots versus untreated, but we’re also getting less lodging, and we have healthier stalks which allows the combine to move quicker into the field and have some harvest efficiency.

When we set up some experiments, we showed that less lodging allowed us to go almost 2 miles per hour faster through the field, resulting in a $23 per acre cost savings.

It’s pretty exciting when you think about the value and the benefit that these products can give to the grower to not only protect against diseases that can reduce yield, but also preserving yield in the presence of abiotic stress like drought and heat.

There are reports of tar spot across the Midwest. What are your recommendations to farmers to manage it?

Harp: If you’re in an area that has tar spot and there are environmental conditions that are conducive to tar spot, we recommend a fungicide application, even if it’s late vegetative or if it’s R1 or R2.

We have acres where we are seeing a benefit from two applications. Most of the heavy lifting is done by the first application. We save maybe 30 bushels from the first application and we do a second application we may get eight to 10 more bushels.

The first application is the most important. Late vegetative to R1 seems to be the best timing for application, and there are tools out there like Tarspotter app from the University of Wisconsin.

Tarspotter uses GPS coordinates to determine if weather has been favorable for the development of tar spot fungus during corn flowering in a specific field. Models in the app use local weather, gathered through the internet, to predict favorable conditions for most corn growing regions. Based on these predictions and crop phenology, a site-specific risk prediction is generated.

Make no mistake, the inoculum is in the field and as soon as the weather conditions get conducive, you get tar spot.

The more preventative you can use a fungicide application, the more yield preservation and more value from that fungicide you’re going to get.

Tom Doran

Tom Doran

Field Editor