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Mitigate this season’s most challenging corn and soybean diseases, including tar spot, with tips from agronomists

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Golden Harvest agronomists offer late-season disease management recommendations for tar spot, Southern rust and Sudden Death Syndrome

DOWNERS GROVE, Ill., USA, Sept. 23, 2021 – Late-season disease management is crucial to protecting corn and soybean yield potential come harvest. Although Corn Belt farmers already facing top 2021 yield robbers are past the prevention stage, the Golden Harvest agronomy team reminds them that it’s not too late to mitigate the diseases’ impact – not only for this season, but for the next as well.

Three of this season’s biggest challenges have been tar spot and Southern rust in corn, and Sudden Death Syndrome (SDS) in soybeans. Here are recommendations from Golden Harvest agronomists to manage them through the remainder of the season:

Respond to tar spot in corn

Although tar spot is relatively new to Midwestern corn fields, it has quickly become a prevalent and problematic disease.

Caused by the pathogen Phyllachora maydis, tar spot weakens a corn plant’s immune system, leaving it susceptible to more infection from other diseases.

“Most of the time, tar spot is not the only disease a corn plant is fighting off,” said Adam Mayer, Golden Harvest agronomist for southeast Minnesota and northeast Iowa. “The addition of tar spot to other common diseases in this area – such as Northern corn leaf blight, gray leaf spot or eyespot can quickly and easily downgrade crop quality.”

Tar spot presents itself as raised, black bumps on the epidermis of corn plant leaves. Once those spots are visible, Mayer cautions that this means the infection is already well on its way.


Phyllachora maydis, the fungus causing tar spot, with and without lesions forming around stromata. Source: Syngenta

“The best control measure for tar spot is going to be prevention,” Mayer said.

As such, residue management in the off-season, crop rotation, limiting the number of corn-on-corn fields and careful hybrid selection should be top priorities for farmers in high pressure areas when planning for next season. Applying Miravis® Neo fungicide is also a good option for preventive control of tar spot.

“The genetic diversity that the Golden Harvest corn portfolio brings to the table really helps us be a leader in tar spot tolerance,” Mayer said. “We’re doing some really good things with Golden Harvest corn genetics to ensure that tar spot doesn’t become a larger epidemic-type issue moving forward.”

Manage Southern rust in corn

Southern rust pressure has been above average across Midwest corn fields during the 2021 growing season, including in the southwest Illinois region supported by Golden Harvest agronomist Nate Prater.

“We usually see Southern rust at a later stage in the season, but this year, it started affecting crops right after pollination,” Prater said. “That means these plants were dealing with the disease during kernel fill, so we’re likely going to see some yield effects.”


Southern rust pustules forming on upper leaf surface. Source: Syngenta

Prater described a Southern rust infection for a corn plant as equivalent to trying to run a marathon with your nose pinched shut and your oxygen cut off. Southern rust causes pustules on the top of plant leaves, preventing sunlight from being absorbed and limiting the amount of energy the corn plant can produce. As a result, the plant will rob that energy from other places, whether that be from the stalk, the kernel size or the kernel depth.

To mitigate the effects of a Southern rust infection at this point in the season, Prater recommends considering an earlier harvest date.

“You may have to change your harvest strategy a little bit,” Prater said. “Instead of waiting until the middle to end of October, it may be beneficial to start harvesting earlier in the fields where you’re seeing lodging and late-season standability issues due to Southern rust infection.”

To get ahead of the issue next season, Prater suggests selecting hybrids with strong tolerance to Southern rust, planting early and applying a quality fungicide such as Trivapro® at the R1 stage, shortly after pollination.

Prevent Sudden Death Syndrome in soybeans

SDS is a chief cause for concern for soybean farmers year after year. This yield-limiting disease starts as a root rot early in the year, before eventually leading to premature death of the soybean plant.

“Over the season, the soybean roots will slowly build up toxins from the soilborne pathogen Fusarium virguliforme,” said Ryan Dunsbergen, Golden Harvest agronomist for southeast Iowa and northeast Missouri. “Then in the case of a rain event, moisture comes into the soybean plant and flushes those toxins through the entire plant.”


Sudden Death Syndrome symptoms in soybean plant roots and leaves. Source: Dean Malvick, University of Minnesota

Although it is too late in the season to control a current SDS infection, Dunsbergen said that it is still important to scout fields now to understand what types of pressure are present.

“Sometimes SDS does not get expressed in soybean leaves, so it’s important to get out and dig roots to understand your current SDS pressure,” he said. “That will help you make the right management decisions for next year.”

When preparing for next season, Dunsbergen recommends choosing varieties with tolerance to SDS, considering a strong seed treatment such as Saltro®, and improving drainage and reducing compaction in fields.

The Golden Harvest portfolio is available from Golden Harvest Seed Advisors, who combine high-yielding seed options with local agronomic knowledge and deliver a Service 365 year-round commitment to doing whatever it takes to yield results for farmers.

To find a local, independent Seed Advisor and gain more information on Golden Harvest corn and soybeans, visit GoldenHarvestSeeds.com.

About Golden Harvest
Golden Harvest Seeds has been rooted in genetics, agronomy and service since 1973, offering in-depth seeds expertise combined with the local agronomic know-how of an independent Seed Advisor to maximize yield potential on each field. Today, every Golden Harvest hybrid and variety is bred with the individual needs of hardworking farmers in mind. Find more information at GoldenHarvestSeeds.com. Follow us on X at www.twitter.com/GldnHarvest and like us on Facebook at www.facebook.com/GldnHarvest.

The content of this release is for information purposes only. This release is not, and should not be construed as, an offer to sell or issue or the solicitation of an offer to buy any securities or other property interests.

Media Contacts:
Erin Skly
312-371-0801
erin.skly@syngenta.com

Sutton Cavalchire
919-886-4934
scavalchire@gscommunications.com

Web Resources:
Golden Harvest
Trivapro
Miravis Neo
Saltro
Newsroom
Thrive

Cautionary Statement Regarding Forward-Looking Statements
This document may contain forward-looking statements, which can be identified by terminology such as ‘expect’, ‘would’, ‘will’, ‘potential’, ‘plans’, ‘prospects’, ‘estimated’, ‘aiming’, ‘on track’ and similar expressions. Such statements may be subject to risks and uncertainties that could cause the actual results to differ materially from these statements. For Syngenta, such risks and uncertainties include risks relating to legal proceedings, regulatory approvals, new product development, increasing competition, customer credit risk, general economic and market conditions, compliance and remediation, intellectual property rights, implementation of organizational changes, impairment of intangible assets, consumer perceptions of genetically modified crops and organisms or crop protection chemicals, climatic variations, fluctuations in exchange rates and/or commodity prices, single source supply arrangements, political uncertainty, natural disasters, and breaches of data security or other disruptions of information technology. Syngenta assumes no obligation to update forward-looking statements to reflect actual results, changed assumptions or other factors.

All photos are either the property of Syngenta or are used with permission.

Product performance assumes disease presence.

© 2021 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties. Please check with your local extension service to ensure registration status. AAtrex 4L, AAtrex Nine-O, Acuron, Agri-Flex, Agri-Mek 0.15EC, Agri-Mek SC, Avicta 500FS, Avicta Complete Beans 500, Avicta Complete Corn 250, Avicta Duo Corn, Avicta Duo 250 Corn, Avicta Duo COT202, Avicta Duo Cotton, Besiege, Bicep II Magnum, Bicep II Magnum FC, Bicep Lite II Magnum, Callisto Xtra, Cyclone SL 2.0, Denim, Endigo ZC, Endigo ZCX, Epi-Mek 0.15EC, Expert, Force, Force 3G, Force CS, Force 6.5G, Force Evo, Gramoxone SL, Gramoxone SL 2.0, Gramoxone SL 3.0, Karate with Zeon Technology, Lamcap, Lamcap II, Lamdec, Lexar, Lexar EZ, Lumax, Lumax EZ, Medal II ATZ, Minecto Pro, Proclaim, Tavium Plus VaporGrip Technology, Voliam Xpress and Warrior II with Zeon Technology are Restricted Use Pesticides.

Some seed treatment offers are separately registered products applied to the seed as a combined slurry. Always read individual product labels and treater instructions before combining and applying component products. Orondis Gold may be sold as a formulated premix or as a combination of separately registered products: Orondis Gold 200 and Orondis Gold B.

Important: Always read and follow label and bag tag instructions; only those labeled as tolerant to glufosinate may be sprayed with glufosinate ammonium-based herbicides. LibertyLink®, Liberty® and the Water Droplet logo are registered trademarks of BASF. HERCULEX® and the HERCULEX Shield are trademarks of Dow AgroSciences LLC. HERCULEX Insect Protection technology by Dow AgroSciences. Under federal and local laws, only dicamba-containing herbicides registered for use on dicamba-tolerant varieties may be applied. See product labels for details and tank mix partners. Golden Harvest® and NK® soybean varieties are protected under granted or pending U.S. variety patents and other intellectual property rights, regardless of the trait(s) within the seed. The Enlist E3® soybean, LibertyLink®, LibertyLink® GT27®, Roundup Ready 2 Xtend®, Roundup Ready 2 Yield® and XtendFlex® soybean traits may be protected under numerous United States patents. It is unlawful to save soybeans containing these traits for planting or transfer to others for use as a planting seed. Only dicamba formulations that employ VaporGrip® Technology are approved for use with Roundup Ready 2 Xtend® and XtendFlex® soybeans. Only 2,4-D choline formulations with Colex-D® Technology are approved for use with Enlist E3® soybeans. The trademarks or service marks displayed or otherwise used herein are the property of a Syngenta Group Company. ENLIST E3® soybean technology is jointly developed with Dow AgroSciences LLC and MS Technologies LLC. The ENLIST trait and ENLIST Weed Control System are technologies owned and developed by Dow AgroSciences LLC. ENLIST® and ENLIST E3® are trademarks of Dow AgroSciences LLC. GT27® is a trademark of MS Technologies and BASF. Roundup Ready 2 Xtend® , Roundup Ready 2 Yield®, XtendFlex®, VaporGrip® and YieldGard VT Pro® are registered trademarks used under license from the Bayer Group.

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