New Soybean Fungicides Target White Mold and Phytophthora Root Rot

Soybean growers looking to protect their crops against prevalent disease issues and maintain high yield potential will have two new fungicide tools from Corteva Agriscience in 2024 to help in the process: LumiTreo fungicide seed treatment and Viatude fungicide.

Viatude, available in a limited supply for 2023, protects soybeans from white mold disease (Sclerotinia stem rot), which can contribute to significant yield loss.

Farmers are spending more than $100 million annually to control white mold, according to Clark Smith, U.S. fungicides product manager for Corteva.

“For every 10% increase in white mold incidence, it could be robbing yields of anywhere between 2 bushels and 5 bushels per acre,” says Smith, citing research from South Dakota State University (SDSU) Extension.

White mold develops when soybean flowering coincides with prolonged air temperatures less than 85 degrees F in combination with frequent rains providing more than 42 hours of continuous wet stem surface or more than 12 hours of surface wetness on a daily basis, according to Connie Tande, SDSU Extension plant diagnostician. These conditions most often take place for early planted, late-maturing soybeans, she adds.

Smith says Viatude already has regulatory approval from the Environmental Protection Agency for use. “We also have state approval in several of our northern states, and we expect to have all of (the additional state approvals) in time for the 2024 growing season,” he adds.

White Mold is a significant disease problem of soybean in the North Central region of the U.S. and Canada.

Severe white mold infection weakens the plant and can result in wilting, lodging and plant death. In addition to causing yield loss, white mold can affect seed quality and seed production, according to the Soybean Research And Information Network.

How Viatude Works

Viatude contains two modes of action that address white mold: picoxystrobin and prothioconazole.

Prothioconazole, a broad-spectrum systemic fungicide, is a member of the triazole-containing class of pesticides (Group 3). It offers protective, curative and eradicative action for white mold disease.

Picoxystrobin is a highly active strobilurin-based product (Group 11), which Corteva has branded globally as Onmira, for the control of foliar and soil-borne plant diseases.

“What's really great about these properties is they quickly surround, penetrate and protect soybean leaves and stems,” Smith says.

He says farmers can use Viatude as part of their comprehensive disease-control system for stronger plant health throughout the year.

University of Wisconsin researchers have developed a white mold forecasting app known as Sporecaster that uses several variables including weather and the amount of soybean row closure in a field. You will need to scout your field to determine if the soybean crop meets thresholds such as canopy closure and the presence of flowers.

For more information on how to use the app, including video tutorials, see “New smartphone app: Sporecaster, The Soybean White Mold Forecaster”.

New Soybean Seed Treatment

Corteva also announced on Tuesday it is expanding its LumiGen seed treatment portfolio with new LumiTreo fungicide seed treatment.

“One of the challenges that our farmers face is Phytophthora, the No.1 yield robber when it comes to early-season diseases in soybeans,” says Brad Van Kooten, seed treatment category leader for the company. “It's a disease that's ubiquitous out there. It's just everywhere we’re planting soybeans.”

Soybeans are most at risk to Phytophthora in poorly drained soils with high clay content that are saturated by rainfall soon after planting. However, Phytophthora can attack soybean plants at any stage of development.

He notes that yield losses to Phytophthora root rot can range widely, from 5% to upwards of 50% in severely affected soybean crops.

Van Kooten says the active ingredients in LumiTreo include oxathiapiprolin, ipconazole and picoxystrobin.

Based on research the company has done over three years in 256 U.S. locations, Van Kooten says “this new soybean recipe will deliver disease protection, in-field performance and plantability.”

LumiTreo also offers protection against common seedling diseases, such as damping off, seedling blight, and seed and root rot.

The product will be available in 2024 at Corteva production facilities and downstream treating facilities, Van Kooten says.

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