There is plenty of concern to go around when it comes to white mold and sudden death syndrome in soybeans. Those are the serious diseases that concern farmers such as Ben Heath — who raises irrigated yellow, white and seed corn; soybeans; and seed soybeans in Fillmore County near Geneva, Neb.

There was some white mold — a new problem in his area — last season in soybeans. “We attribute this to the amount of irrigation that was needed late season on soybeans, not allowing the canopy to dry out,” Heath explains.

“I think a lot of us got caught off guard last year when white mold showed up in soybean fields in August,” Syngenta agronomist Travis Gustafson says. “Typically, dry weather doesn’t help promote white mold progression, but with the drought last year, many farmers started running irrigation around Memorial Day just to keep soybeans alive. This created the conditions ideal for white mold infection, which takes place in late June.”

Favorable for white mold

Gustafson also notes that last season, there were plenty of days perfect for spraying crops. “What does this have to do with white mold? When the wind doesn’t blow and we can spray, we won’t have much air circulation in the soybean canopy, which again can drive conditions favorable for white mold development,” he explains.

Related:Lessons learned from 2023 soybean season

As for SDS, cool, wet conditions at planting or shortly after will create the potential for the disease to thrive.

“As we move our soybean planting dates earlier each year, we are going to encounter more fields that will see SDS develop,” Gustafson says. “However, I’m not going to recommend delaying planting to manage SDS, because that could cause a grower to lose yield potential by planting later. I do think it will be a disease we need to manage for every year on every acre.”

Choosing the correct genetics is the first step in managing both diseases. Every seed company rates its seed for diseases such as SDS and white mold, so choosing varieties that have the best defense package against the disease threat producers see as their most dangerous is a way to prevent damage, Gustafson adds.

“Maybe you will find a variety that yields well and has defense against both diseases,” he says.

Fungicide treatment as a tool

Fungicide treatments are tools in the battle. “You’ll need a seed treatment to protect against SDS, like Saltro, and you’ll need a well-timed foliar fungicide for white mold, like Miravis Neo,” Gustafson says. “The best time to apply a fungicide for white mold is when the first flowers come out in the second half of June. If you have a field with known history of high-pressure white mold, you may need a second fungicide application.”

With SDS or white mold, if producers have seen them in the field, it is likely they will see them again.

“It’s hard to monitor SDS, so we will always have to manage preventively because any management practices — like variety selection and seed treatment — will have to be implemented before we know if conditions will be favorable for SDS,” Gustafson says.

“With white mold, I’d start to watch weather patterns around Memorial Day,” he adds. “If the first half of June will be heavy with irrigation needs, then I’d consider making a fungicide application toward the second half of June.”

There are other factors such as canopy closure and variety sensitivity that can affect a decision about acting on white mold.

Preventive action

Heath continues to especially worry about white mold going into this growing season, because he knows it is in his area.

“One R3 fungicide application has provided us with good disease control to this point, but in the 2024 growing season, we are more proactive in soybean disease management,” he says. “We have been trialing multiple fungicide applications and timing, along with the addition of other stress-mitigation products like amino acids, to keep the plants as healthy as possible and to fight off any diseases we may encounter.”

Premium products with multiple modes of action and timing applications before disease pressure is observed have paid dividends for Heath in the form of better yield response, he says.