Syngenta Thrive

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Weeds represent a significant economic threat to growers across the country. Identifying weeds and remaining vigilant through regular scouting is critical to formulating a proper plan. Uncontrolled or mismanaged weeds can damage crops, compete for resources, contribute to herbicide resistance and slow harvest. According to Cornell College of Agriculture and Life Sciences, incorrectly identifying problem weeds can mean the difference between profit and loss.

Waterhemp vs. Palmer Amaranth

Palmer amaranth and waterhemp are two of the most widespread and devastating yield-robbers growers face, with populations in almost every corn- and soybean-growing region in the U.S. To make matters worse, the International Herbicide-Resistant Weed Database Weed Science map shows that populations of both weeds exhibit herbicide resistance.

These pigweeds are frequently misidentified, but a few key characteristics help set them apart.

Waterhemp

A close-up aerial view of a cluster of waterhemp weeds.
Short petioles help distinguish this cluster of waterhemp from Palmer amaranth.

An AgWeb poll asked about 400 growers what their “top weed nemesis” was. Unsurprisingly, waterhemp took the top spot, earning 35% of the votes.

Waterhemp is a small-seeded broadleaf weed that compensates for its tiny seed size with a fast growth rate. Its lightweight seeds thrive in minimum and no-till situations, where they germinate quickly near the soil surface or in crop residue. Plants generally produce about 250,000 seeds per plant, although some can produce as many as one million seeds, making them a prolific and costly problem for growers.

Waterhemp emerges throughout the growing season, but a higher percentage appears later than most annual summer weeds. This allows waterhemp to escape many preemergence herbicide applications and persist after post-emergence applications, especially those with no residual, like glyphosate, or limited residual. Waterhemp plants that are left to go to seed can quickly populate the soil seed bank with millions of seedlings, increasing resistance and ensuring costly management issues for years to come.

Look for:

  • Waxy, oar-shaped seedling leaves.
  • Hairless stems that range from green to red-pink in color.
  • Glossy alternate true leaves that are oval or lanceolate in shape.

Palmer Amaranth

A close-up, aerial view of a cluster of Palmer amaranth weeds.
Long petioles help distinguish this cluster of Palmer amaranth from waterhemp.

Another broadleaf weed, Palmer amaranth shares many characteristics with waterhemp. Its small seeds thrive in minimum tillage fields. Plants can produce at least 100,000 seeds when in competition with a crop and almost 500,000 seeds in non-competitive scenarios. If escaped weeds get the chance to produce seed, they can cause serious consequences for future seasons. Like waterhemp, Palmer amaranth persists after non-residual or limited residual herbicide applications. Palmer amaranth has been steadily spreading northward in recent years and continues to raise alarms for herbicide resistance.

Palmar amaranth’s emergence period extends well into the growing season. Out of the many tough weeds growers need to scout for, Palmer amaranth may be the most unpredictable. Start scouting early and continue throughout the growing season to stay in control.

Look for:

  • Oval- or diamond-shaped seedling leaves.
  • Alternate true leaves that are alternate and lanceolate in shape.
  • Smooth and hairless stems.
  • Seed heads that grow up to 30 inches long.
  • A single hair at the leaf notch of the first few true leaves can sometimes, but not always, distinguish Palmer amaranth from waterhemp.

Even experienced growers may still confuse these two weeds. When in doubt, the University of Nebraska-Lincoln recommends a few tips to help growers tell the difference between waterhemp and Palmer amaranth:

  1. Palmer amaranth cotyledons tend to be longer and narrower compared to waterhemp cotyledons.
  2. True leaves on Palmer amaranth may be notched at the tip; hairs are less common on waterhemp seedlings.
  3. If the petiole is shorter than the leaf blade, the weed is probably waterhemp. Palmer amaranth, on the other hand, has petioles that are as long as or longer than the leaf blade.

Proper identification is more difficult after the flowering stage, so don’t let weeds mature before scouting.

How to Identify Common Weeds

Although waterhemp and Palmer amaranth dominate headlines across the Midwest and Central Plains, there are plenty of other tough weeds that should be on your radar.

Common Ragweed

A close-up photo of common ragweed.
Hairy stems, fern-like weeds and green flowers are identifying characteristics of common ragweed.

Common ragweed is an aggressive broadleaf weed from the aster family. According to Michigan State University, one common ragweed plant per 10 square feet can cause a 30% yield reduction in soybeans and average 3,500 seeds per plant.

Look for:

  • Common ragweed grows to 1-3 feet in height.
  • Purple seedling stems and dark green, paddle-shaped cotyledons.
  • Green leaves that are deeply divided into lobes.
  • Branched and hairy stems.
  • Fern-like leaves 2-4 inches in length with longer stalks on lower parts of the plant.
  • Clusters of green male and female flowers.

Giant Ragweed

Giant ragweed growing in a field of soybean seedlings.
Rough, heavily lobed leaves and weed height are indicators of giant ragweed.

Another aster, this large-seeded broadleaf can reach heights of up to 20 feet and has a big appetite for your crop’s resources. Giant ragweed typically emerges several weeks prior to corn and soybean planting. It is especially difficult to control because giant ragweed seeds germinate deep within the soil profile.

Look for:

  • Thick, fleshy cotyledons.
  • Heavily lobed leaves that are rough to the touch.
  • Opposite leaf arrangement as the plant develops.
  • Weed height that is 1-5 feet taller than the crop with which it is competing.

Common Cocklebur

Common cocklebur growing in a corn field.
Stiff hairs on the surface of leaves help growers differentiate between common cocklebur and other weeds.

At the seedling stage, this weed is easily confused with giant ragweed because the long cotyledons of the two species look similar. However, common cocklebur emerges closer to the end of planting. Cocklebur’s large leaves intercept a lot of sunlight, making it a highly competitive yield reducer.

Look for:

  • Triangular or oval leaves that are approximately 2-6 inches in length.
  • Stiff hairs on the surface areas of the leaves.
  • Three veins extending from the same point on the upper side of the leaf.
  • Long petioles.

Horseweed (Marestail)

A dense patch of marestail growing in a farm field.
Marestail leaves get progressively smaller toward the top of the plant.

While this weed may germinate year-round in different geographies, it typically is seen in late summer or fall, and in early spring. Knocking out this weed before its highly mobile seeds spread throughout fields offers the best chance of control.

Look for:

  • A basal rosette with oval to egg-shaped leaves soon after emergence.
  • Alternate true leaves that are hairy and irregularly toothed.
  • Leaves that decrease in size toward the top of the plant in a sessile leaf pattern.
  • Growth up to 6 feet tall.

Common Lambsquarters

Common lambsquarters growing in a field.
The mealy white coating on this weed indicates it is common lambsquarters.

This early-emerging weed is one of the most competitive species, particularly due to its rapid growth rate. Each plant produces an average of 72,500 seeds, which are some of the most resilient in the soil seed bank.

Look for:

  • Veinless seedling leaves that are opposite and narrow with rounded tips.
  • Triangular, alternate and dull green true leaves with undulate to toothed margins.
  • A mealy white coating on leaf surfaces.
  • Small green flower clusters at the tips of the main stem.

How to Contain Weeds

Although a handful of weed escapes may not be enough to steal away your yields, the presence of just one weed opens the door for hundreds or thousands more next season.

The first step to manage weed escapes is proper identification. While many herbicides are labeled for a variety of common weeds, knowing exactly what’s in your field informs more efficient and effective programs. Herbicide programs with multiple effective sites of action, strong overlapping residuals and full use rates will result in the most complete control of labeled weeds.

For soybeans, start with a strong preemergent herbicide, such as Tendovo® followed by a post-emergence herbicide option like Dual Magnum® or Flexstar® GT 3.5 for overlapping residual control and resistance management.

For corn, start with a strong preemergence herbicide application of Storen®, Acuron® or Acuron Flexi. Either can be applied in one pass or in a two-pass program with a foundation rate preemergence followed by the remaining rate post-emergence. Additionally, Acuron GT herbicide is a post-emergence option that delivers fast knockdown and enhanced control of difficult weeds like waterhemp. It can be applied as part of a two-pass program following an application of  Lexar® EZ or Lumax® EZ herbicides. All these solutions include multiple sites of action for resistance management and offer application flexibility.

Talk to your local Syngenta retailer or sales representative to plan a program tailored to tough and resistant weeds in your fields.

If timing doesn’t allow for herbicide applications, control escapes with methods like cultivation or hand-pulling. If pulled weeds have flowers or seed heads, make sure they are bagged, removed from the field and destroyed to make sure there is no chance of spread to your fields or your neighbor’s. Properly identifying and removing just one waterhemp or Palmer amaranth plant can mean the difference between a clean start to the next season and hundreds of thousands of emerging weeds.

Harvest Corn and Soybeans, Not Weeds

After a season of hard work, getting every possible bushel out of your acres is key. If you see weeds in your fields at harvest, consider some of these harvesting tips outlined by the United States Department of Agriculture:

  1. Avoid harvesting corn and soybeans located in areas densely populated with weeds — the risk of spreading weed seed is likely not worth the bushels you might get from that field.
  2. Adjust your combine’s cutting height settings to minimize the amount of weed seed that is harvested. Consulting with your combine provider helps determine the right height for your field conditions.
  3. Regularly clean your farm equipment between harvesting different fields to avoid contamination from weed seed.
  4. Destroy all weed seed left in the field after harvest to prevent it from entering the soil seed bank. Burning weed seed is a common method to get rid of it.
  5. Before taking your harvest to the elevator, be sure to examine corn and soybeans for weed seed upon arrival and to separate weed seed through mechanical cleaning or other means.
  6. An application of a harvest aid like Gramoxone® SL 3.0 herbicide can help keep the combine running smoothly by eliminating remaining weeds in soybean fields.

Taking these actions to minimize contamination from weed seed will help ensure your hard work pays off and will help prevent weeds from growing on your farm in the future.

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June is National Safety Month — an annual observance sponsored by the National Safety Council to remind all of us to stay safe in the workplace and in our daily lives.

When it comes to safety, Syngenta focuses on the proper use of its products, according to Caydee Savinelli, Ph.D., the U.S. stewardship team and pollinator lead at Syngenta. Numerous educational opportunities are available to help users learn about product safety.

Online Trainings Ensure Compliance

Syngenta provides webinars to help fulfill the paraquat training requirements put forth by the Environmental Protection Agency (EPA). “For paraquat users, EPA requires training every three years. Each state tracks the trainings to make sure users are in compliance,” Savinelli says. “Syngenta conducts atrazine training with farmers as well to ensure that the product stays on the field and does not reach waterways. We also support the Growing Matters’ BeSure! campaign for the proper use of neonicotinoids.”

An illustration of a laptop with a honeybee on the screen and a notepad, with text that reads "Online trainings help ensure compliance."

Additionally, the stewardship team works with university pesticide safety education programs, supports the National Pesticide Safety Education Center, participates in the American Association of Pesticide Safety Educators, and helps county extension agents.

“Each of these groups provides important pesticide safety education to farmers, applicators and other users,” Savinelli says. “Without this infrastructure, it would not be possible to reach all of the people who use our products.”

Correct Product Disposal Enhances Farm Safety

While using products safely is critical, properly disposing of containers following use is also important. Through its decades-long collaboration with the Ag Container Recycling Council (the Council), Syngenta is helping customers do just that.

According to Scott Birchfield, manager of environmental stewardship and emergency response at Syngenta, the goal of the partnership with the Council is to help customers properly dispose of product containers while keeping their properties, workspaces and the environment safe.

“With the recent focus and deeper understanding of the environmental impacts of plastic pollution, many companies are looking for solutions to reduce their environmental footprint,” Birchfield says. “Syngenta has been on the forefront of this effort for over 20 years.”

An illustration of ag containers accompanies the text: Correct product disposal enhances farm safety."

Syngenta recognizes the importance of sustainability and is committed to providing customers with simple ways to contribute to a healthier environment. From proper application to mindful disposal, Syngenta encourages all customers to participate in environmental stewardship.

“Because this program is free, participation is easy and helps customers achieve their environmental goals,” Birchfield says. “We all want to do everything we can to help ensure our environmental footprint is as small as possible.”

Farm Kids Get Specialized Trainings

As part of its commitment to farm safety, Syngenta also supports the work of Progressive Agriculture Foundation®, whose mission is to help keep farm children safe. Progressive Agriculture Safety Day® is recognized as the largest rural safety and health education program for children in North America.

An illustration of a farmer with his arm around the shoulders of a child looking over the fields. The text reads: "Farm kids get specialized training."

Progressive Agriculture Safety Day provides age-appropriate, hands-on educational lessons primarily designed for children ages 4 to 13 years old. Since the program’s inception in 1995, it has reached more than 2 million individuals in 45 states, two U.S. territories and nine Canadian provinces.

Farming is a serious profession with numerous safety considerations. Syngenta is committed to collaboration, education and stewardship practices to help keep everyone safe, both during National Safety Month and all year long.

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Despite the dynamic nature of weed communities, the discovery of new species is uncommon and can spell trouble for growers. This year, Iowa farmers should keep their eyes peeled for an emerging weed threat: Asian copperleaf.

Discovered in 2016, Asian copperleaf has been found in corn and soybean fields in six counties in North Central Iowa (as of June 2024). It’s unclear how the plant was introduced, but Iowa farmers have seen it emerge in dense patches late in the season. While other weed species typically stop growing once corn and soybeans reach canopy closure, Asian copperleaf is shade tolerant and actually thrives under the canopy.

Should I Be Concerned About Asian Copperleaf?

A USDA Risk Analysis found that Asian copperleaf shows no strong invasive or weediness characteristics, but researchers still classified 57% of simulations as high risk due to a high amount of uncertainty. To make matters worse, Asian copperleaf threatens row crop yields and has developed resistance to several herbicide groups in its native range.

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As with any weed, we would expect some yield loss if it’s left unchecked. This particular species has definitely caused yield loss in its native range and is certainly something that we want to keep an eye out for.

Jesse Grote Agronomy Service Representative at Syngenta

“As with any weed, we would expect some yield loss if it’s left unchecked,” says Jesse Grote, an Iowa-based agronomy service representative at Syngenta. “This particular species has definitely caused yield loss in its native range and is certainly something that we want to keep an eye out for.”

Scouting and Identifying Asian Copperleaf

Scouting this weed can be tricky. Grote recommends scouting in July, around the time growers look for corn rootworm, and continue through harvest.

“Here in Iowa, growers primarily notice it at harvest since it stays below the canopy,” says Grote. “If you’re harvesting your field and come up on a weedy patch that you weren’t expecting, hop out and see if you can identify it as Asian copperleaf.”

To determine if a weed is Asian copperleaf, first rule out other spurges by breaking the stems of suspicious weeds. Unlike other common spurge species, Asian copperleaf does not have milky sap inside the stem.

From there, rule out other species like Virginia and rhombic copperleaf by examining the bracts. “It really comes down to the bracts,” says Grote. “If you’re going to look for anything, the heart-shaped bracts are the one characteristic that distinguishes this from other copperleaf species.”

A close up photo of the bracts of an Asian copperleaf plant.
Asian copperleaf has unique heart-shaped bracts that set it apart from other spurge species.

What to Do if You Find Asian Copperleaf

There are still many unknowns when it comes to managing Asian copperleaf. Following the principles of proper weed management as researchers uncover more information is critical. That means starting clean by using strong rates of residual herbicides and following up with overlapping residuals.

As harvest approaches, special considerations should be made to manage Asian copperleaf. “If you’re combining and identify Asian copperleaf that has gone to seed, be extra cautious to prevent transporting seed or anything that could potentially propagate in another field,” says Grote. Be sure to clean equipment between fields and be mindful of what’s going into the combine.

“Something to consider for this type of weed, because it’s living below the canopy and we may not find it until harvest, is a fall application of a burndown herbicide or a tillage pass to make sure it doesn’t get to seed,” says Grote. Although these methods may not be typical for the region, the extra precaution may pay off when dealing with a new threat.

Researchers are still examining the impact and spread of Asian copperleaf. If you suspect Asian copperleaf on your farm, please contact the Iowa Department of Agriculture and Land Stewardship at 515-725-1470.  Reach out to your local Syngenta retailer or representative for more information about tackling tough and emerging weed threats.

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The folks at the Syngenta manufacturing site in St. Gabriel, Louisiana, have made it standard practice to forge ahead in their endeavor to help farmers feed the world and improve it for future generations. This is accomplished through the theme of giving back and protecting the environment.

Recently, the St. Gabriel manufacturing facility was recognized by the U.S. Environmental Protection Agency (EPA) Green Power Partnership program as a top 100 green power user in the country. The program works with businesses across the country to promote the voluntary use of green power, defined as being generated in the U.S. from renewable resources, which include solar, wind, geothermal, biogas, eligible biomass and eligible low-impact hydroelectric sources. Syngenta is the only organization from the agricultural sector to be named to the Green Power Partnership’s top 100 list, a recognition they are both honored and humbled by.

“Why green power? At Syngenta we’re trying to build sustainability into everything we do,” says Alan McMurry, site sustainability lead at the St. Gabriel facility. “A lot of our sustainability goals revolve around renewable agriculture practices that generally help feed the world in the most sustainable way. One of our priorities is sustainable operations; so, with the products we make at St. Gabriel, we want to walk the talk and have our operations run as efficiently and sustainably as possible.”

Implementing Sustainable Practices

St. Gabriel formulates and packages liquid and powder forms of Syngenta products like Acuron® corn herbicide, Halex® GT herbicide, Gramoxone® SL 2.0 herbicide, Lexar® EZ corn herbicide, and Sequence® herbicide, along with more than a dozen others. To keep up its constant production of so many trusted products, the Syngenta plant employs about 350 full-time employees and another 450 independent contractors.

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A lot of our sustainability goals revolve around renewable agriculture practices that generally help feed the world in the most sustainable way. One of our priorities is sustainable operations; so, with the products we make at St. Gabriel, we want to walk the talk and have our operations run as efficiently and sustainably as possible.

Alan McMurry Site Sustainability Lead, St. Gabriel Facility

With so much production happening in one place and doing so much to make the American farmer more sustainable and efficient than ever, it’s understandable the site would have a rather large carbon footprint. But being okay with that justification and sticking with the status quo isn’t in the DNA here. Syngenta has made enormous strides in decarbonizing its operations, and the St. Gabriel site is the poster child for that effort.

“Syngenta has really made sustainability a core function,” says McMurry. “So, we asked the question, ‘How do you decarbonize your own operation?’ We came up with a number of strategies, but one of the biggest ones is using renewable electricity.”

About 30 percent of the site’s carbon footprint can be attributed to electricity usage — some 151 million kilowatt-hours a year, roughly the equivalent of the power consumption of 14,000 American homes.

Once the commitment was made to pursue green power, the question became, Where do we get this green power? Precious few solar or wind farms exist in eastern Louisiana, so the sustainability team at the site had to do some shopping. Of course, the question of where raised several more questions: What’s the right type of power for our operation? How do we get the power here? How do we best implement it at our site? Should we build our own solar and/or wind farms? Ultimately, Syngenta used a Renewable Energy Certificate (REC) purchasing strategy for solar and wind power, much of it from power producers in Arizona’s high desert country and the plains of West Texas.

And in 2023, the St. Gabriel site happily reported REC purchases for every single one of those 151 million kilowatt-hours from renewable power sources, what the EPA calls ‘green power.’ “Syngenta wants to lead the way with agriculture manufacturing in the U.S.,” says McMurry. “We really dove into that and are proud that we were able to achieve 100 percent of the site’s electricity moving to green power.”

Though electricity is currently the biggest piece of the pie, McMurry and his team are also making strides in decarbonizing the plant’s heat production, using fewer utilities and cutting back on waste.

McMurry is also excited about a more recent development outside the company that should have a major impact on the St. Gabriel plant’s ability to utilize green energy in its operations. In early 2024, the Louisiana Public Service Commission approved construction of two large solar farms in the state. Both are already under construction, and Syngenta intends to utilize green tariffs, which are optional programs offered by utilities to allow commercial and industrial customers to purchase bundled renewable energy, to obtain some of the electricity from those farms once they go online.

“We’re excited to buy local and to support the ones who are ‘growing’ the renewable power,” McMurry says. “Louisiana is starting to build more of that now and there’s room to grow, so we’re trying to support it. We’ve committed to being part of those solar farms.”

Giving Back Through Community Outreach

Another important Syngenta pillar is community involvement. While the manufacturing site is only a half-hour’s drive from the state capitol building in Baton Rouge, St. Gabriel maintains a close-knit, small-town feel. A large portion of the plant’s employees were hired from within the existing community of 6,500, and company leadership doesn’t take lightly the impact the facility has on all the residents — more than its role as one of the area’s largest employers. Syngenta makes a point to contribute time and resources to the areas where its employees live and work. Employees actively host and participate in several educational and community activities throughout the year.

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Reagen Simpson (standing) and Eldred Stewart (sitting) keep a close eye on the plant’s reactors.
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Josh Domingue, plant superintendent (left) and Reagen Simpson, lead process engineer/FF&P (right) are two of the 350 full-time employees working at the St. Gabriel plant.
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St. Gabriel Multi-Purpose Facility Unit, where two Syngenta products are made.
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Syngenta St. Gabriel employees donate time and resources to the community of St. Gabriel by helping senior citizens, donating to the food bank, mentoring high school students, and much, much more.
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St. Gabriel Community Center, used by St. Gabriel employees for staff meetings and community events for the children and senior citizens of St. Gabriel.
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Syngenta, St. Gabriel Plant. Annually, 950 railcars and more than 18,000 tanker trucks filled with Syngenta products depart the facility for distributors and farms across the country.
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Syngenta employees enjoy coming together to volunteer on clean-up day for the town of St. Gabriel, mentoring high school students on their career paths, and interacting with students on Moving Forward Mondays.

Kim Argrave, executive administrator at the St. Gabriel site, plays a primary role to get the St. Gabriel team involved in the surrounding community. When asked about some of the projects she’s worked on, Argrave excitedly starts ticking them off on her fingers.

“We have a career awareness program with the two local schools. Syngenta provides and organizes STEM projects during the school year and during summer camps for the students,” she says. “We also have events with senior citizens. We donate to local causes, try to hire local residents, and we offer scholarships to local students. We’re just really involved in the community.”

Syngenta also has a mentorship program that provides basic professional training to high school students entering college and job markets. Here, employees teach participants skills such as filling out an application, practicing interviews, even the proper way to tie a necktie. Tours of the site are also offered not only as a recruiting tool, but as a token of transparency with the neighbors.

“We try to encourage people — especially students — at these career awareness programs, to give them confidence,” Argrave says. “We want them to be involved in their community and their own education and development.”

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Encouraging Employee Efforts

Of course, that strong desire to be a part of the community lends itself to a strong sense of community within the company and the plant itself. The passion for sustainability has embedded itself in a large portion of the plant’s workforce — not just those on the sustainability team.

“We have a little slogan around here: ‘Doing your part with small steps makes a big impact,’” McMurry says. “Employees regularly ask me, ‘Can you tell me what we’re doing?’ People want to know what they can do in their roles [to help with our sustainability efforts].”

Every team at the St. Gabriel site, from engineering and manufacturing to custodial work, office staff and logistics are getting closer to being on the same page in the sustainability book. McMurry also sees progress throughout the entire agriculture industry; there is a growing sense of unity and idea-sharing that he welcomes wholeheartedly. The EPA recognition of Syngenta, he believes, is a strong indicator of agriculture’s leadership in the sustainability realm going forward.

“That vision is expanding,” McMurry says. “Sustainability isn’t just some circle off to the side of our manufacturing. We have a good start, but it should really grow into everything we do.”

The people at St. Gabriel would be doing what they’re doing regardless of any kind of recognition. They’ve never needed someone else to tell them they’re making a difference; they’ve known it all along.

“We’re doing this completely voluntarily because we want to say with authority that we’re making our own products more sustainably,” McMurry says.

And that makes all the difference in the world.

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Gray leaf spot is one of the most yield-limiting corn diseases in the Corn Belt. The pathogen that causes gray leaf spot, Cercospora zeae-maydis, thrives in extended periods of warm, humid weather. Its only known host is corn and it overwinters in crop residue. This makes gray leaf spot especially concerning for farms that operate with corn-on-corn planting and minimum tillage.

The University of Minnesota Extension describes the first sign of the disease as small, pinpoint lesions surrounded by yellow halos. Further along in development, lesions become long, narrow and rectangular, and can vary from brown to gray in color.

Growers can differentiate between gray leaf spot and Northern corn leaf blight by examining the underside of affected leaves. Unlike Northern corn leaf blight, gray leaf spot lesions are typically limited to the veined side of leaves.

Although scouting is a crucial part of disease management, the incubation period for gray leaf spot can be 27 days or more, so crops can be infected well before lesions appear in the weeks leading up to tasseling. This can lead to significant unexpected yield loss.

Severe gray leaf spot infections hinder photosynthesis and therefore decrease yields in two ways:

  1. University of Nebraska-Lincoln Extension research shows reduced photosynthesis limits the number of kernels produced by each ear.
  2. When corn plants can’t draw enough energy from the sun for grain-fill, starches are drawn from the stalks, which can increase lodging at harvest.

Proactive disease management is key to minimize the risk of damage and yield loss. There are several steps growers can take before finding gray leaf spot in their fields.

  • Plant tolerant hybrids. No current corn hybrids or inbreds have complete resistance to gray leaf spot, but some more tolerant hybrids can do well in moderate to high disease pressure.
  • Consider conventional tillage and crop rotation. This strategy can help reduce the amount of pathogen buildup in your fields.
  • Apply a reliable foliar fungicide with proven activity against gray leaf spot. Miravis® Neo fungicide delivers broad-spectrum preventive and curative control to protect corn yields and help boost your bottom line. Trivapro® fungicide delivers long-lasting residual control of gray leaf spot and other key diseases. Miravis Neo and Trivapro both also deliver plant-health benefits to help better preserve potential yield under high or low disease pressure.

A combination of these practices can help maximize yield and ROI potential even under heavy disease pressure. For more information about Miravis Neo, Trivapro and gray leaf spot, reach out to your local Syngenta representative or retailer.

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While soybean aphids haven’t been much of a problem over the last few years, they do have the potential to be harmful — particularly in soybean fields with pressure from other insects. Soybean aphids are a unique and challenging insect, especially when you are trying to eliminate them from your soybean fields. These adaptive, invasive insects only reach 1/16 inch in length. Yet, what they lack in size is made up for in quantity.

Scouting for Soybean Aphids

In the summer, soybean aphid populations boom. With high birth rates and short generation times, populations can double every two to three days when conditions are right. Aphids in overcrowded fields can produce winged forms that easily spread to neighboring fields. Depending on the temperature, growers can expect up to 18 generations of soybean aphids from May to August.

You’ll know you’re dealing with soybean aphids when you spot small, pear-shaped yellow insects with black cornicles near the rear. These pests are typically found on the underside of soybean leaves. As aphid pressure increases, white flakes become more apparent on the surface of leaves. These are the cast skins of molting nymphs.

Another reliable indicator of soybean aphids is the presence of natural predators like lady beetles and minute pirate bugs. Often, ants will be easily visible on the stems of plants affected by soybean aphids.

Why Worry About Soybean Aphids?

Due to their high reproductive potential, a few soybean aphids can quickly become a serious threat. Feeding damage can weaken plants and make them more susceptible to other stressors like drought and disease. Soybean aphids extract plant juices through their needle-like mouths and excrete honeydew, a sugary waste product. Sooty mold can develop on the honeydew excretions and cause yield losses of up to 40%.

Aphids pose the greatest threat to soybean yield during the R1-R4 stages. When contemplating treatment, consider the growth stage of the plants, other stressors and natural predators. Treatment may not be necessary if plants are in later growth stages, if stressors are low or if there are many natural predators in the fields.

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The University of Minnesota Extension  recommends scouting and counting aphids throughout the growing season. If the average number of aphids on each plant exceeds 250, this means that the economic threshold is reached and an insecticide application is needed to protect your yields from damage. This threshold is considered the tipping point because insecticide applications at lower pressure may not pay for the cost of application.

If the economic threshold is reached, effective insecticides like Endigo® ZCX are necessary to prevent economic injury. Endigo ZCX contains two complementary modes of action to protect yields from soybean aphids and other insect pests. For more information about the economic threshold and solutions for your soybeans, contact your local Syngenta representative.

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When it comes to combatting tough pests, nothing beats advice from local experts. Learn about the top weed, disease, and insect pest threats in the Midwest, Mid-South and Southeast before they show up in your fields. Plus, get tips for scouting, preventing and treating tar spot, stink bugs and Palmer amaranth in your corn and soybean fields.


Infographic outlining the top three pest threats to look out for in the 2024 growing season, including tar spot, stink bugs, and Palmer amaranth. Descriptions of each pest include appearance, habitat and ideal conditions, the type of damage it inflicts on crops, and agronomic tips to prevent each pest.

Tar Spot

Stink Bug

Palmer Amaranth

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1 https://www.noaa.gov/news/us-had-its-warmest-winter-on-record

2 https://www.canr.msu.edu/news/msu-researchers-identifying-corn-tar-spot-management-strategies

3 https://www.agweb.com/news/crops/corn/you-cant-afford-be-complacent-about-tar-spot

4 https://www.extension.purdue.edu/extmedia/bp/bp-90-w.pdf

5 https://www.youtube.com/watch?v=CI62h71g6qQ

6 https://www.canr.msu.edu/ipm/Invasive_species/brown_marmorated_stink_bug

7 https://extensionentomology.tamu.edu/insects/redbanded-stink-bug/

8 https://www.epa.gov/safepestcontrol/brown-marmorated-stink-bug#:~:text=In%20the%20United%20States%2C%20the,in%20the%20mid%2DAtlantic%20region

9  https://edis.ifas.ufl.edu/publication/IN1176

10 https://site.extension.uga.edu/benhillcoag/files/2022/08/Redbanded-Stink-Bugs.pdf

11 https://www.mda.state.mn.us/palmeramaranth

12 https://www.fsa.usda.gov/Assets/USDA-FSA-Public/usdafiles/FactSheets/archived-fact-sheets/palmer_amaranth_nrcs_national_factsheet.pdf

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What does it take to plan an effective insecticide program for your tree nuts? Pest management programs should start with good monitoring protocols, knowing how to identify when it’s the right time for treatment.

According to the University of California IPM program, the initiation of hull split is the most effective timing for a single insecticide application. Once you are at 1% hull split and pest flights are present, it’s time to put an effective insecticide program in place to protect your quality and yield potential. Otherwise, these pests can wreak havoc on your tree nuts and even cause fungal infections.

Controlling NOW

Tree nuts are most vulnerable to damage from pests during hull split, as the exposed nut gives navel orangeworm (NOW) and other secondary insects direct access to the nut inside. Larvae bore into the nutmeat and produce large amounts of webbing and frass as they grow. This feeding leads to fungal infections and contamination.

When applied properly and at the right time, a strong pest management plan can help you protect your tree nuts and maximize yield potential from the mummy nut phase through harvest. It’s recommended that you apply a first spray at early hull split and follow-up with a second spray around 10-14 days after.

Navel orangeworm damage on an almond.
Navel Orangeworm larvae and damage in almonds. Source: Syngenta USA Project 2021. Huron, California, USA. Almonds. Westside Harvesting.

Defend Against Spider Mites

In addition to NOW, spider mites are also a major problem pest that you should look out for. Mites can damage your foliage by extracting from your trees’ leaves, causing them to turn yellow and fall off. High numbers of mites can also cover tree terminals with webbing. The University of California IPM program found that crop reduction and reduced vegetative tree growth typically shows up the year after damage occurs.

According to the Sacramento Valley Orchard Source, spider mite management can be accomplished through one of two general approaches:

  • The threshold and biological control approach helps maintain a balanced ratio of natural enemies-to-spider mites that will allow the beneficials to help suppress spider mite populations by only treating spider mites once economic thresholds are reached, not before.
  • An early-season prophylactic approach can be very effective in controlling mites well into summer. However, there could be a downside that may contribute to a later season mite flare up as treatments wear off.
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The key to managing and preventing further infestation of damaging pests is to get ahead of them early with a May spray and continue to treat orchards every two to three weeks to maintain control.

Effective Insect Management

With powerful pest management tools, growers and consultants can execute a customized plan to stay ahead of pests throughout the season.

  • Minecto® Pro insecticide is a broad-spectrum foliar insecticide that controls navel orangeworm and other damaging secondary pests, including mites in tree nuts. Flexible enough to fit into any management plan, complementary ingredients cyantraniliprole and abamectin combine to form a convenient premix formulation that protects against multiple overlapping pest populations such as mites and navel orangeworm. A May spray application of Minecto Pro is important if there are remaining mummies on the trees from the prior season and the time to consider a proactive spray for mites.
  • Besiege® insecticide provides dual-action protection against the most difficult lepidopteran pests, including navel orangeworm, peach twig borer, codling moth, leaffooted plant bug and walnut husk fly. With long-lasting residual and outstanding knockdown, Besiege is ideal for application at hull split.

Building an insecticide program with a combination of these products can help you manage insects in your orchards this season.

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Throughout the course of the almond growing season, there’s always the potential for disease to strike, damaging not only your quality yield potential, but also the overall health of your trees if not properly controlled.

It Starts at the Roots

Like the foundation of your home, the roots of your almond trees play a critical role in the support of your orchards. It’s important to protect your roots so that diseases like Phytophthora root rot and crown rot don’t creep in during dormancy. The soil and roots are important drivers for plant processes that can’t continue if the roots are compromised. To help ensure the long-term health of your orchard, you should be scouting often and applying effective fungicides at the right time to achieve the best yield potential.

The wet and warm conditions during the growing season can create the perfect environment for diseases. Phytophthora root rot is an infection that occurs around the lateral part of the root system of crops, which causes a gradual waning of tree health and productivity that can linger for years. Phytophthora crown rot is an infection that occurs close to the base of the tree, underground, which plugs the vascular system leading to a ghostly death in as early as a week.

Orondis® fungicide is a solution that promotes overall tree health and longevity by combatting multiple Phytophthora pathogens. An application of Orondis during spring root flush can set you up for success in the following season by helping to improve root mass, leading to better nutrient and water intake. It is also recommended to make a second application post-harvest to prevent Phytophthora pathogens from making an appearance when temperatures are high and the soil is damp in the late summer.

A chart shows reduced Phytophthora propagule count with Orondis fungicide.
Orondis protects roots by reducing Phytophthora propagule count and inoculum potential.

Protect Buds and Blooms

Tree nuts are susceptible to a variety of early-season diseases that can be harmful to growing nuts, detrimental to yield and impact the overall health of the plant. Blossom blight is one of the most devastating diseases an almond tree might encounter because it can kill an entire stem.

Warm, humid climates with extended periods of wetness, as well as previous year infections, foster the pathogen that causes disease. Infected fruit mummies on the orchard floor and left in the tree produce spores. The pathogen infects blooms which turn brown and collapse. Infections can extend to the twig and young leaves resulting in gumming and cankers on the stem.

To prevent infections, prioritize good orchard sanitation and make the first recommended fungicide application just before bloom at the pink bud stage. An application of Miravis® Prime fungicide will help dial up your defense against the most damaging diseases like blossom blight. Powered by ADEPIDYN® technology, Miravis Prime offers long-lasting disease control to keep trees healthy and improve almond quality.

A bar chart shows that Miravis Prime protects almond yield potential from brown rot blossom blight.
Miravis Prime protects almond yield potential from brown rot blossom blight.

Optimize for Growth

As spring transitions into summer, your almond trees are hard at work maturing kernels to full size. As the outer hull begins to develop, diseases like Alternaria leaf spot can creep in and rob you of your profit potential.

Alternaria leaf spot disease is typically prevalent from spring to summer and causes large brown spots on leaves that turn black as the fungus produces spores. Like many diseases, it can overwinter in plant debris from the previous year and favors high humidity and wet springs. Keep an eye out for leaf spots to prevent potential yield loss and defoliation.

A preventative application of a strong, broad-spectrum fungicide during this critical growth period is the best way to protect your trees from devastating disease and improve the longevity of your crop. Miravis Duo fungicide targets and prevents these tough diseases using a combination of ADEPIDYN technology and difenoconazole, giving your trees the best chance at potentially producing a quality yield for many seasons to come.

A bar chart shows Alternaria leaf spot protection in almonds with Miravis Duo.
One application of Miravis Duo outperforms competitors in protecting against Alternaria leaf spot in almonds.

A Season-long Approach

Don’t wait for diseases to strike your almond orchards. Syngenta offers a season-long approach to help you manage disease not only in the current growing season, but in future seasons to come. Contact your local representative to develop an effective management plan that works for you.

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Reach for your trusty Farmers’ Almanac to predict this season’s weather, but turn to Syngenta agronomy service representatives (ASRs) for the latest on this season’s most threatening pests. These ASRs use their regional experience and knowledge to predict which insects, weeds and diseases you should scout for in 2024.

Midwest Growers: Watch Out for Waterhemp and Tar Spot

Indiana

Waterhemp is a driver weed in the ‘Hoosier State’ according to Chad Threewits, Syngenta ASR in Fort Wayne, IN. Poor weed control last year increased this year’s seed bank, he says, adding that Canada thistle and giant ragweed will also be a factor in both corn and soybean fields.

It’s predicted that pre- and post-emergence herbicide applications will be crucial to limiting prolific weeds this season — and are an investment in future crops as well. “Developing herbicide programs that help control these driver weeds not only keeps fields clean this year but helps limit the pressure by reducing the seed bank for the future,” Threewits says.

As in many regions, tar spot is now Indiana’s driver disease in corn. “It’s shown up everywhere in the state, and the severity will depend on summer weather,” Threewits says. Moderate temperatures and wet weather can drive tar spot development, while hot, dry days can decrease its impact. However, don’t bet on the weather to stay on your side.

“The timing of fungicide needs to occur right at the onset of tar spot,” Threewits says. “A lot of growers want to wait, but to maximize yield we can’t let it get ahead of us.”

Some other molds may keep Indiana corn and soybean growers up at night. Ear mold and white mold were big problems in 2023, so they’re top of mind again this year. Threewits also advises soybean growers to keep an eye out for bean leaf beetles and stink bugs, especially late in the season.

Illinois

Illinois growers can expect to battle waterhemp this season according to Kevin Scholl, Syngenta ASR in northern Illinois. “I always say if waterhemp is not your main target weed, it’s going to be. You’ve got to get it under control to have a successful harvest,” he says.

Scholl says waterhemp is a late-season emerger; he recommends a two-pass program with a pre-emergent herbicide followed by an early post-application. “The bigger it gets, the harder it is to kill. That’s why we try to stay ahead of it,” he says.

The top-of-mind disease in corn is, not surprisingly, tar spot. Scholl says northwest Illinois endured one of the nation’s first major outbreaks in 2018, which left a legacy not just in the fields, but in the way growers treat other foliar diseases in corn.

“The 2018 tar spot outbreak changed the way we make recommendations for diseases like gray leaf spot, Northern corn leaf blight and common rust,” he says. While they used to advise tassel to green silks as the best timing for fungicide application and plant-health benefits, Scholl says it now depends on the disease’s timing.

“If tar spot comes in earlier than that timeframe, we need to pull the trigger and spray a fungicide when we see it start to build, especially if the weather conditions are conducive,” he says.

Likewise, soybeans need early intervention to prevent Sudden Death Syndrome. “Sudden Death Syndrome infects the plant early in the season but doesn’t really show itself until the soybeans start to flower,” Scholl says. “For control early in the season, we’ve had very good luck with Saltro® fungicide seed treatment.”

Scholl says the primary insect pest in corn continues to be corn rootworm, which packs a one-two punch by chewing away at corn roots as larvae, then clipping silks as mature beetles. “The beetles lay their eggs in the fall, in corn fields or sometimes in soybean fields, so you can’t really get around this pest with just rotation,” he says. “I advise planting a traited-hybrid seed and applying an insecticide right at planting.”

An insecticide like Force® Evo or Force 6.5G can help protect the corn’s roots. “If you’re losing root mass, you’ll lose the capacity to bring up moisture and nutrients, and that plant’s going to suffer in the end,” Scholl says.

Central Plains Growers: Beware of Palmer Amaranth and Tar Spot

Kansas

The biggest weed threat in western Kansas continues to be Palmer amaranth according to T.J. Binns, Syngenta ASR in Kansas. “It’s a difficult weed to control due to its prolific seed production, rapid growth rate and continuous emergence through the growing season,” he says.

“Palmer amaranth takes work to manage in a perfect year. In 2023, a big hail weather event opened up the canopy late in the season which allowed even more Palmer to go to seed,” Binns says. “So, we’re expecting it to be an even bigger challenge in 2024.”

All Kansas row crops are affected by Palmer amaranth, but Binns says it’s especially damaging in grain sorghum (milo). “In milo, there really aren’t any herbicides to control Palmer amaranth once they emerge. It’s a helpless feeling when it happens,” he says.

To limit weed impact in corn and soybeans, Binns recommends robust rates of pre-emergence herbicides followed by early application of overlapping residual herbicides before the weed comes up.

“We’re moving in the same direction with milo — overlapping residuals and a quality pre-emergence product,” he says, adding that in this crop, timing is crucial. Binns also notes a warmer-than-normal spring could cause Palmer amaranth to emerge earlier than usual in all crops.

Wheat growers will want to be mindful of stripe and leaf rust, along with Fusarium head blight (FHB), which could undermine a promising crop. “FHB has become more common in the last few years and a lot of growers were caught by surprise with the amount of infection in 2023,” Binns says.

Growers impacted by FHB last year have already taken steps to protect against it in 2024 by making variety selections that offer higher levels of tolerance for the disease. “Variety selection is the first step,” Binns says. “But even with variety selection, they need to be considering a Miravis® Ace fungicide application, ideally at bloom if the weather conditions are conducive for FHB infection.”

Binns also advises growers to be aware of rust progression from the south and start preventative fungicide applications as soon as the flag leaf is 50% emerged — before the rust lesions appear on their wheat.

Nebraska

ASR Travis Gustafson’s territory, Nebraska, has a lot in common with neighboring Kansas. Palmer amaranth is a big concern in both corn and soybeans, and control depends on pre- and post-emergence herbicides if growers want the upper hand.

In corn, Storen® herbicide has performed well in demo trials for the last couple of years, Gustafson says, and he expects it to be a premium choice for managing Palmer amaranth in 2024. For soybeans, he recommends growers rely on Group 15 residual herbicides to control the pest, such as Boundary® 6.5 EC, Tendovo® and BroadAxe® XC.

“These herbicides provide great small-seeded broadleaf residual control early in the season and provide a foundation for more residual activity with post-emergence applications,” Gustafson says. He adds that it’s important to use residual products in both pre- and post-emergence applications to hold back later-germinating Palmer amaranth before the soybean canopy closes.

Gustafson warns Nebraska corn growers to be on the lookout for tar spot. Last year, tar spot showed up late in Nebraska and had no impact on yield — but now that it’s here, growers must be more vigilant.

“Be more observant of tar spot lesions throughout the season,” Gustafson says. “We’re also watching out for southern rust, northern corn leaf blight and gray leaf spot.”
Miravis Neo and Trivapro® fungicides have built a reputation for high performance in the field for control of tar spot and other fungal diseases, he says. As fungicides with exclusive active ingredients ADEPIDYN® or SOLATENOL® technology respectively, Miravis Neo and Trivapro can also help the crop through stressful situations, like drought, by delivering plant-health benefits during grain fill.

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Mid-South Growers: Prep for Aphids, Stink Bugs and Palmer Amaranth

Kentucky and Tennessee

Aphids and Fusarium Head Blight (FHB), the fungal disease also known as head scab, are the pests to watch out for in wheat this year according to Sarah Gehant, Syngenta ASR for Kentucky and western Tennessee.
“CruiserMaxx® brand seed treatment controls fall aphids and should be followed with Warrior II with Zeon Technology® insecticide in the spring,” Gehant says. She advises the importance of controlling aphids all season long, as they can transmit barley yellow dwarf virus in cereals, damaging both yield and quality.

An expanding weed pest in the region is ryegrass. A successful burndown program is critical for getting this weed under control. Gehant recommends an application of Boundary herbicide coupled with Gramoxone® SL 3.0 when going to soybeans or an application of Sequence® herbicide when going to corn or soybeans. Both programs provide residual control, so it is an excellent foundation to setting growers up for success.

Kentucky’s insect to note is stink bugs in soybeans. “Stink bugs were bad last year and we expect it to be worse this year,” she said. “Endigo® ZCX insecticide will do a great job when combined with Miravis Top fungicide at R3.”

Mississippi

Despite its diverse cropping system, which includes cotton, sorghum and rice, soybeans are still the biggest crop to be found in Mississippi, with more than two million acres planted. Palmer amaranth is the big weed to watch out for, according to Tripp Walker, Syngenta ASR in Mississippi.

“The direct weed competition is the biggest issue, because it develops right along with the crop,” he says. “So, we’re trying to avoid those competition-type losses. In a worst-case scenario, failure to manage Palmer amaranth can result in direct crop loss.”

The Mississippi weather promotes disease pressure including frogeye, septoria and target leaf spot in soybeans. Walker says reproductive-stage growth applications of Miravis Top provides good contact and residual control of a host of foliar diseases.

Stink bugs in general, and red banded stink bugs in particular, are at the top of Walker’s insect-threat list for 2024. “Stink bugs feed on the developing seeds, so it is a direct crop loss,” he says. “But the Endigo ZCX premix provides both contact and residual on red banded stink bugs, as well as other stink bugs and insect pests we see in soybeans.”