Now is the time for those critical fungicide applications

Mid-to-late July is the critical point of the growing season for many farmers across the country, which means it is time for many growers to consider fungicide applications.

Concept AgriTek’s Daniel Hensley offers up some tips for assessing the need for a fungicide, and then choosing a fungicide that is appropriate for the situation.

“Should I use a fungicide or should I not use a fungicide? Will a fungicide pay or will it not pay?” Hensley said. “Those are the questions that are often asked, and I believe that a fungicide will pay way more than it doesn’t pay. As I explain it to guys, it’s like an insurance policy. We hope we don’t need, but thank goodness it’s there if we do.”

Step 1: Assessing the situation

To know if a fungicide application is necessary, a farmer first needs to pay close attention to local and regional conditions.

“What does disease pressure look like in their area? Have they been wet? Have they been hot and dry? Are the conditions conducive to that application?” Hensley asked. “We have to take all that into consideration.”

It means collecting reports on challenges that not only plague neighboring farms, but those that are encroaching on the region and those that are exhibiting signs of starting in one territory and making a charge toward their area.

“See if we have Southern rust coming. See if common rust or gray leaf spot are starting to show up,” Hensley said. “If you know something’s there, then get out to your crop and see if you’ve got it yet. If you don’t have it, consider yourself lucky, but protect yourself against it. If it’s been a good year, pressures are really low and you’re not seeing much disease, well, maybe it might be a year that you opt not to use a fungicide, but there’s not many years like that, quite frankly.”

And if disease has found its way into your fields?

“Let’s try to stop it” with a fungicide application, Hensley said. “And once you have all the facts, that will help in your decision making process.”

Step 2: Choosing the right fungicide

There are various factors that determine the fungicide that’s best for the situation. Realistically, the most important factor is budget.

“After that, You have to figure out how you’re going to apply my fungicide,” Hensley added. “If I can get through my corn at v10 and I don’t want to pay for an airplane, then I want to use something with a very long residual. If you can use an airplane and you’re going to get out there and your (corn) is at brown silk and your budget is not very high, then you’re going to use a generic fungicide.”


A crop duster sprays fungicide on a potato field.

Hensley said that growers who find disease in the field will have to use a curative, but those without disease should opt for a fungicide with protective properties.

“If you want both, you can use a dual mode of action fungicide—securitive and protective—in the same package,” Hensley said. “It’s all going to be circumstantial for each farmer.”

Common fungal problems detected in 2021

While there is recorded and anecdotal evidence of many varieties of diseases throughout the country, there have been some that have been more prevalent than others.

“Common rust and Southern rust have both been problematic, and I know gray leaf spot has hit,” Hensley said.

According to the Crop Protection Networkcommon rust pustules appear as cholorotic flecks on the leaf’s surface. They develop into powdery, brick-red pustules as the spores break through the leaf surface. Pustules are oval or elongated, about 1/8-inch long, and scattered sparsely or clustered together. The leaf tissue around the pustules may become yellow or die, leaving lesions of dead tissue. The lesions sometimes form a band across the leaf and the entire leaves will die if severely infected. As the pustules age, the red spores turn black, so the pustules appear black, and continue to erupt through the leaf surface. Husks, leaf sheaths and stalks also may be infected.

Southern rust is similar to common rust, but pustules are smaller and occur almost exclusively on the upper leaf surface. Pustules are usually circular or oval, very numerous and densely scattered over the leaf surface Spores are orange when they erupt from the pustule. As pustules age, they become chocolate brown to black, often forming dark circles around the original pustule. Southern rust thrives in high humidity and temperatures around 80 degrees Fahrenheit.

Gray leaf spot initially appears as small, light tan lesions on plant leaves and then as grayish lesions confined by corn veins. The lesions spread to higher leaves as the infection cycle repeats.

Information about other diseases common to American agriculture can be found at


How Concept AgriTek can help

Concept AgriTek’s certified agronomists can help you assess your farming operation’s biggest disease threats and make suggestions for preemptive or curative fungicide treatments.

“We can help with our new biological fungicide, Bio-Aid,” Hensley said. “We can also come look at their field and give them our opinion as far as disease pressure.”

He added that Concept AgriTek regularly fields calls from farmers across the country because they know Concept AgriTek agronomists closely monitor disease conditions from coast to coast and can quickly spot trends and can often address problems before they reach a grower’s fields.

“Guys up north will call and ask ‘What’s it’s looking like in the South? Just how much pressure is the rust down there?’” Hensley said. “Typically, it blows out of the Gulf (of Mexico) and it just blows right up the Mississippi River. They call us because they want our eyes and ears and our feet on the ground to help them determine what’s coming.”

To put Concept AgriTek’s expert agronomy team to work for you, visit, email, or call (888) 638-9984.

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