Farm Progress

Spraying fungicide: Time of day matters

Corn Illustrated: When you have a choice, spray fungicides in the morning.

Tom J. Bechman, Midwest Crops Editor

May 21, 2024

3 Min Read
Illustration showing how much fungicide lands on crop leaves
TIME MATTERS: This illustration showing how much fungicide from a spray application lands on leaves makes a case for spraying in the morning. Tom J. Bechman

Getting corn sprayed with fungicide can be a tense situation, especially if you’ve spotted disease symptoms and you’re depending on a commercial applicator. But what if you have your own rig? Are there ways to make more money based on when and how you apply the fungicide?

Jim Schwartz, director of research for Beck’s, believes there are opportunities. The first opportunity starts with choosing what time of day to spray. While that’s hard to do if you’re hiring fungicides custom-applied, it should be easier if you spray your own fungicides.

“Farmers asked us to look, so we did studies in our Practical Farm Research program at various locations around the Corn Belt,” Schwartz says. “We saw an advantage for spraying at 8 a.m. versus 3 p.m. in the afternoon in both corn and soybeans.”

Is spraying early worth it?

Next, the team looked to explain why they saw a difference. They used a technique that allowed them to collect spray patterns on a surface simulating spray patterns on a leaf. Applications indicated particles were present on more surface area when sprayed at 8 a.m. vs. 3 p.m.

“We believe it likely has something to do with the presence of dew on most mornings at 8 a.m.,” Schwartz explains. “Dew droplets may help spread spray particles across the leaf. When spraying at 3 p.m. on a typical day, leaves are dry and there are no moisture droplets remaining.”

Yield differences for spraying early vs. midafternoon were not dramatic, but they were consistent. After repeating the same test for three years at multiple locations and averaging the results, there was a $10.17-per-acre return on investment over costs for spraying at 8 a.m. vs. 3 p.m. in corn. Spraying the fungicide at either time vs. not spraying a fungicide produced a significant yield and profit increase.

For soybeans, the average ROI for 8 a.m. vs. 3 p.m. over three years was $5.34 per acre. Again, applying at either time produced higher yield and profit than not applying fungicide.

“If a practice pays three years in a row, we consider it a PFR Proven practice,” Schwartz says. “Spraying fungicide in the morning versus afternoon has been PFR Proven for three years now.”

Carrier volume matters

Similarly, increasing carrier volume in fungicide applications in a three-year study in Beck’s PFR program also paid, Schwartz says. In corn, the biggest gain comes when going from 10 to 15 gallons per acre of carrier. Over three years, just upping carrier volume from 10 to 15 gallons and changing nothing else boosted return on investment over $10 per acre. Going from 15 to 20 added about another 70 cents per acre.

In soybeans, the jump was biggest going from 15 to 20 gallons per acre. Going from 10 to 15 gallons per acre added about $2.50-per-acre ROI, but going to 20 boosted ROI another $7 per acre.

“We strongly recommend growers consider 20 gallons per acre for fungicide applications on soybeans,” says Steve Gauck, a regional agronomy manager for Beck’s. “It requires handling more liquid, but increased performance makes it worth it.”

Increasing volume to 15 or 20 gallons per acre from the standard 10-gallon carrier rate is also a Beck’s PFR Proven practice.

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About the Author(s)

Tom J. Bechman

Midwest Crops Editor, Farm Progress

Tom J. Bechman became the Midwest Crops editor at Farm Progress in 2024 after serving as editor of Indiana Prairie Farmer for 23 years. He joined Farm Progress in 1981 as a field editor, first writing stories to help farmers adjust to a difficult harvest after a tough weather year. His goal today is the same — writing stories that help farmers adjust to a changing environment in a profitable manner.

Bechman knows about Indiana agriculture because he grew up on a small dairy farm and worked with young farmers as a vocational agriculture teacher and FFA advisor before joining Farm Progress. He works closely with Purdue University specialists, Indiana Farm Bureau and commodity groups to cover cutting-edge issues affecting farmers. He specializes in writing crop stories with a focus on obtaining the highest and most economical yields possible.

Tom and his wife, Carla, have four children: Allison, Ashley, Daniel and Kayla, plus eight grandchildren. They raise produce for the food pantry and house 4-H animals for the grandkids on their small acreage near Franklin, Ind.

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