Superintendent Magazine - November, 2012


The Disease Dilemma

With the weather getting warmer, the window for turf disease is getting wider. What do fungicide manufacturers think of the phenomenon?
By Larry Aylward

So much for the tattered manila folder in your filing cabinet that contains your turf disease records, including the date you make your first preventive fungicide spray of the season.

Considering the warming trend over the past few years - the first eight months of 2012 were the hottest ever recorded in the continental U.S., and the summer period of June, July and August was the third hottest ever - your turf disease records are as out of date as the fax machine collecting dust behind the stack of golf magazines in your office.

Thanks to an extremely fickle Mother Nature, it's getting difficult to gauge a fungicide program. The growing period for bentgrass and bermudagrass is getting as long as the drawn-out NBA season, which means a wider window for disease pressure.

That window opened in March, when temperatures hit 80 throughout the country, and still hadn't closed in late October. Many superintendents made their first applications for dollar spot in February and March. The summer was hot and dry in the Midwest, so disease pressure was not as high as it has been in the past. But with hot, wet conditions on the East Coast, disease pressure was soaring. Superintendents in the lower transition zone who maintain bentgrass greens had a particularly long season.

"The warmer temperatures have certainly extended the period of time in which turf diseases can be problematic," says Jill Calabro, regional field development manager for Valent U.S.A.

If the warming trend continues, golf course superintendents wonder what adjustments they'll have to make to their fungicide programs.

Will they have to spray earlier, more often and later into the season?

Will they see certain diseases earlier than usual?

Could they see new diseases because of the warming trend?

"The weather the past few years has brought superintendents back to the reality that you have to expect the unexpected every year when you are growing turf," says Matthew Seibel, territory sales manager of the Great Lakes region for Arysta LifeScience.

What's causing it?

So, what's causing the warming trend? Conventional wisdom points to global warming.

Consider that average temperatures have climbed 1.4 degrees Fahrenheit around the world since 1880, according to the National Aeronautics and Space Administration. The United Nations' Intergovernmental Panel on Climate Change says that 11 of the past 12 years are among the dozen warmest since 1850.

While Seibel isn't so sure global warming is to blame, he can't help but notice the extremes in the weather the past few years.

"The past three years have been pretty brutal for managing turf," he says.

Calabro believes that global warming is what's causing the planet to heat up.

"There's a tremendous amount of evidence that points to the fact that we are definitely in a warming trend, and it doesn't seem to be natural," she adds.

Jerry Corbett, technical services/product development manager for Quali-Pro, thinks that weather patterns work in 20-year cycles, and the cycle is currently in a warming pattern. Besides, the weather is always changing, he says.

Lane Tredway, senior technical field representative for Syngenta, says he can't make an educated guess on what's causing the warming trend, but that it's easy to blame a new disease outbreak or a new disease trend on it.

"In reality, there are so many other things that influence turf that could be leading to that change," Tredway adds.

Owen Towne, president of Phoenix/UPI, gives credence to the fact that the temperature is rising, but whether it's global warming or not, it really doesn't matter, he says.

"Whatever the reason, it's incumbent on the supplier to make sure superintendents have the products they need based on the weather they're experiencing at that point and time," Towne states.

Corbett predicts that fungicide sales will be generally higher this year because of the mild winter across the country. But Calabro isn't so sure because she says overall pesticide applications have been reduced because of decreased maintenance budgets.

"My sense is we aren't seeing an increase in fungicide use because superintendents are being more efficient with their applications and selecting materials where they can target several diseases at once," Calabro explains.

Jimmy Johnson, fungicide product manager for Environmental Science, a division of Bayer CropScience, says the number of fungicide applications may have decreased the past few years because superintendents have been using other tools to maintain healthy turf and prevent disease, from cultural practices to plant health-related products.

"There are a lot more preventive tools today than there were 10 years ago," Johnson adds. "I see that trend continuing."

The impact

Global warming or not, the warming planet is impacting superintendents' fungicide programs around the country.

Quali-Pro's Jerry Corbett says the onslaught of several diseases at once were hard to identify.

Calabro says disease was "all over the place" last spring. Many diseases were coming up at once. For instance, summer patch occurred about one month early, around the same time as dollar spot.

Corbett says the onslaught of several diseases at once - which he calls complex diseases - were difficult to identify. He notes that superintendents on the East Coast saw more dollar spot and anthracnose on their courses than they ever have. Corbett says anthracnose wasn't the problem 10 years ago that it is now.

"The talk then was always about dollar spot, brown patch and Pythium," Corbett says. "Now I hear more about anthracnose and odd diseases like yellow ring patch."

With longer growing conditions, superintendents can count on dollar spot pressure lasting longer, too, says Kyle Miller, senior technical specialist for BASF. Because they're only allowed to spray chlorothalonil four times a year, superintendents may have to find one or two more fungicides to use in rotation with chlorothalonil. The longer dollar spot persists, the greater the potential for it to become resistant to fungicides used in rotation with chlorothalonil.

"That's up to the superintendent to do what he needs to do to keep that from occurring," Miller says. "There are a lot of fungicides to choose from, so it shouldn't be an issue. But superintendents have favorite fungicides and tend to overuse them at times."

The wider window also affects applications for snow mold control, Miller notes. Superintendents prefer to apply fungicide for snow mold soon before a snow cover, which slows down the degradation of the fungicide in the soil. But if the snow never comes, then the fungicide degrades faster, which means they might have to make another application in January, he says.

It's not just the heat that's beating up bentgrass, Miller adds. It's the maintenance, too.

"We've gone through a period where we continue to give golfers the highest turf quality possible and that means more management of the turf, such as lower mowing heights and rolling," Miller says. "The turf is under more stress because of that."

Combined with the severe heat and longer growing conditions, "it just makes things twice as bad," Miller says.

Towne says current fungicides are so effective at treating the major diseases that they give secondary diseases a chance to emerge, such as Rhizoctonia.

"We've done a better job of controlling primary diseases, but the secondary or tertiary diseases could become more common," he adds.

In the transition zone, one way superintendents are dealing with heat-related disease on cool-season turf is by converting to warm-season turf. Golf courses throughout the transition zone have been switching greens from bentgrass to ultradwarf bermudagrass.

Syngenta's Lane Tredway says superintendents can keep up with what's going on with turf disease through social media like Twitter and Facebook, as well as other superintendents' blogs.

Corbett says ultradwarf bermudagrass can get its share of disease, too. In fact, he says dollar spot is becoming more of a problem on it. Also, in recent years, some courses from the Carolinas to Texas are dealing with the Rhizoctonia leaf and sheath spot on bermudagrass greens.

"In the heat of the summer, when its 95 degrees and high humidity, the bermudagrass won't die," Corbett says, "but you still have to keep disease under control. "

The more bermudagrass that's planted, the greater the disease pressure, Tredway adds.

"Any time we change something in terms of what grass we're growing and how we're managing that grass, Mother Nature will respond with new pests," he adds.

Sound advice

If superintendents learned one thing from 2012, which could go down as the warmest year in history, it was that they have to be ready at all times for whatever Mother Nature throws at them.

"Be prepared to do battle," Miller says.

Regarding dollar spot control, superintendents can get a leg up on it by treating for it in the late fall, even if it isn't visible, Miller notes. That way, the dollar spot inoculum in the soil is reduced come spring.

Corbett advises superintendents to photograph the diseases they see on the course and makes notes about the conditions when they occur. And when treating, don't forget to rotate fungicides. And when rotating, don't combine the same mode of action.

"In other words, don't rotate a DMI (demethylation inhibitor) with a DMI," Corbett adds.

Towne advises superintendents to stop using fungicides that contain solvents that can burn turf in hot weather.

One of the best ways for superintendents to treat disease complexes is by using combination products, experts say. Many chemical manufacturers have released (and will continue to release) combination products to achieve broad-spectrum disease control.

"That's the key," says Corbett, noting that Quali-Pro has a new fungicide coming out next year that contains four active ingredients.

Corbett also suggests that superintendents take advantage of the communication tools at their disposal, such as weather apps that can be downloaded to smartphones.

Tredway says superintendents can keep up with what's going on with turf disease through social media like Twitter and Facebook, as well as other superintendents' blogs.

One of the best ways for superintendents to treat disease complexes is by using combination products.

"Social media gives superintendents a way to connect with one another in real time," he adds. "I encourage superintendents to get connected, whether it's with their local universities, extension specialists or their colleagues, so they can form support networks."

Superintendents should also attend local field day events, Calabro says.

"That's where you find out what the new problems are and what the new products are [to treat them]," she notes.

Johnson points out that fungicide suppliers also have to do their part. When turf disease arrived earlier this year, Johnson realized that Bayer had to work with its distributors to make sure certain fungicides were available when they needed to be.

Manufacturers' plans

It's tough to create new fungicides if you don't know what diseases will be prevalent in 10 years, which is the time it usually takes for a new active ingredient to reach the market. But fungicide manufacturers know they have to stay on top of things.

"If we have a bigger window for disease pressure, we just can't keep throwing the same products at them," Seibel says. "We have to bring new products to the table to meet the demands."

Oftentimes, it's a balancing act.

"We're looking for solutions to address future needs while taking into account the concerns and issues of the day," Johnson says.

While BASF continues to identify fungicides to provide solutions to turf disease problems, the company is researching other ways to help turfgrass make it through stressful times, Miller says. That would be the company's plant health focus. BASF is not alone in that initiative. Bayer, Syngenta and other companies are also going down that path.

Thanks to the warming trend, Mother Nature has thrown down a gauntlet of challenges for superintendents, but fungicide manufacturers face their own demands.

"Every day is a new adventure," Towne says.

Aylward can be reached at 330-723-2136 or