Managing White Mold in Peanuts

Having a plan to manage pest and disease pressure can substantially increase peanut yield potential. Hunt Sanders, field market development specialist, and John Altom, territory account manager, discuss how peanut growers can help control yield-robbing diseases such as white mold.

Commodity markets are known to weigh heavily in farmers’ production decisions. Growing conditions and timing can tip the scales, too. For growers in the Southeast, that can mean choosing to plant peanuts.

As peanut acres shift, growers often plant peanuts either back-to-back or on rotations shorter than three years, says Hunt Sanders, field market development specialist for Valent U.S.A. “We'd like to have at least a three-year rotation with peanuts. With many of our growers on short rotations, we expect to see more white mold.”

What is white mold?

Southeast peanut growers know that white mold and other diseases can rob them of yield, decrease crop quality and hamper marketability.

Annually one of the most devastating diseases of peanuts in the Southeast, white mold is a soilborne pathogen, and a fungal disease caused by Sclerotium rolfsii. White mold attacks the crown in the plant's roots, the tap root, and the plant's crown.

The combination of moisture early in the season, followed by extreme heat and late-season dry conditions can cause white mold to rapidly spread in a field. When the growing season is wet and cool, white mold is less prevalent.

Get ahead of white mold disease

The most effective way for peanut growers to battle white mold is to prevent it before it occurs. Getting out in the fields to scout crops early and often throughout the season provides the knowledge necessary to manage and control disease outbreaks.

When scouting for white mold, it is critical to look for symptoms above and below ground. Wilting, especially of the plant’s flag leaf, is often the first visible sign of white mold. White mycelia, or moldy growth covering the plant’s stems near the soil line, is another visible disease symptom. The crown of the plant, at or just below the soil line, may also be necrotic (yellowing), and sclerotia, which can look like small animal droppings, may be found on plants infected by white mold.

If a crop is infected with white mold, adjusting fungicide programs can help control white mold before it overtakes more plants.

Excalia® Fungicide: The preventive treatment for white mold

Combatting white mold disease requires a tool that gets to work quickly, even in heavy pressure situations, and results in season-long control. A Group 7 succinate dehydrogenase inhibitor (SDHI) fungicide, Excalia offers fast-acting, systemic and translaminar movement into the plant.

Excalia also offers growers flexibility in application and low use rates. Excalia can be applied between 30 and 100 days after planting, with treatments of 3-4 ounces per acre recommended at 45- and 60-day timings. Alternatively, a three-spray program would require applications of 2 ounces per acre at 60 and 90 days after planting, with a maximum application rate of 8 ounces per acre per season.

“We've been testing Excalia with the University of Georgia, Clemson University and Auburn University since 2015, and I have to say that the results have been extremely consistent. Excalia is a top performer that’s as good, or better, than any fungicide on the market for white mold and rhizoctonia control,” Sanders says.

For more information about Excalia, visit, or hear more from John Altom and Hunt Sanders on the Field Advice podcast.

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Valent Field Advice podcast logoHunt Sanders, field market development specialist, and John Altom, territory account manager, discuss how peanut growers can help control yield-robbing diseases such as white mold.

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