Keep Bushels off the Ground: Early Fungicide Application Helps Corn Stand Straight and Healthy

April 24, 2018

keep bushels off the ground: early fungicide application helps corn stand straight and healthy
Foliar fungicides applied early in the season are a good risk-management tool for growers who are pushing for top yields.

How much do lodged corn plants cost you in bushels, higher labor costs and fuel expenses — not to mention general aggravation?

Yield losses can be significant in downed corn, as many growers saw in 2017 when October windstorms flattened crops across the Midwest. Especially with low corn prices, you need to put every possible kernel in the hopper.

A fungicide application between the V4 and V7 growth stages can protect cornstalk vitality and keep your crop standing straight until harvest, said Thorsten Schwindt, Bayer fungicides product manager.

“Harvesting is all about speed and efficiency, and an early fungicide application helps ensure standability," Schwindt said. "This is one of the main benefits of an early application.”

A critical growth period

Between V4 and V7, corn plants go through a critical growth period that has a big impact on yield potential, said Randy Myers, Bayer fungicides product development manager. By V4, the seed’s starch reserves are depleted.

“Now the plant must be self-sufficient,” Myers said.

Often, though, Midwest soils are still cool, inhibiting phosphorus uptake. The nodal root system is expanding and ear shoots and tassel are forming. Stresses on young plants in this vulnerable phase can result in fewer ear kernel rows. Fungal disease symptoms usually are not visible in this period — and may not develop for quite some time.

Diseases can be both foliar and in the stalks. Stalk rots may not be obvious for much of the season, but they can still be weakening the stalks.

“However, an early season fungicide application can deliver physiological benefits beyond disease control,” Myers said. Strobilurin fungicides applied early can help corn tolerate yield-robbing environmental stresses, he said. That translates into healthier plants that deliver top yields.

Bayer solutions for corn disease management

Foliar fungicides applied early in the season are a good risk-management tool for growers who are pushing for top yields, Schwindt said. Delaro® 325 Fungicide can give your high-yielding hybrids the protection they need. Its advanced formulation delivers broad-spectrum disease control, a best-in-class dual mode of action residual and improved plant health.

An application of Delaro fungicide between V4 and V7 can:

Piggyback on your post-emergence herbicide

Delaro is compatible with many post-emergence crop protection products. For cost efficiency and convenience, Delaro can be tank mixed with herbicides and applied in one trip across the field.

Maintain stalk health

An early fungicide application increases cell wall lignification, Myers said. Lignin helps keep stalks strong so they are less likely to fall over or snap off in strong winds. In addition, healthy green stalks support good nutrient flow and increased photosynthesis during grain fill, Schwindt said.

An early application of Delaro typically boosts yield, too — but it’s not always the main reason growers use it, Schwindt advises. “I know many growers who make planned applications just because it improves standability. They consider yield increases a secondary benefit.”

Delay disease symptoms

"Many foliar diseases progress up the plant like a ladder,” Myers said. “For example, gray leaf spot and northern corn leaf blight survive in the residue from prior corn crops. They typically infect the lower leaves first, and spores from those infections are carried by wind and rain to higher leaves." An early fungicide application shields lower leaves, helping the middle canopy stay disease-free longer. While an early application of Delaro does not provide season-long control of foliar diseases, it does keep lower leaves clean until they are shed, he said.

Boost stress tolerance

An early application of Delaro can help young corn plants withstand environmental stresses such as wind, hail and dry weather, Schwindt said. It can also assist plants in using scarce resources such as water, nitrogen and phosphorus more efficiently –offsetting physiological effects that can occur even without disease. This promotes better plant health during stressful growing conditions.

Protect yield

“Foliar infections can occur at any plant growth stage, and the earlier infections develop, the greater the damage,” Myers said. Delaro offers unmatched preventive and curative defense against gray leaf spot, northern corn leaf blight, anthracnose leaf blight, southern corn rust and other common fungal diseases. By keeping plants healthier, an early application of Delaro can improve the odds that your corn crop will fulfill its genetic potential.

In 2017, field-scale trials across the Midwest showed a V4 to V7 application of Delaro increased corn yields by an average of 7 bu. per acre.

Before applying any fungicide, please read the entire label for the best possible results and to confirm the product is effective on the disease you need to control. Not every product is suitable for every situation, and correct application technique will ensure the best results.

For more information on corn disease management solutions, contact Bayer.

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