Stine® Seed Company agronomists are cautioning growers to be on high alert for sudden death syndrome (SDS) and iron deficiency chlorosis (IDC) in soybeans. Both field issues are exacerbated by cool, wet environments — a fitting description for the planting and growing seasons in parts of the northern and eastern U.S.
“For many growers out East, it has been a wet, cold spring, and crops have been slow growing and under stress,” says Bill Kessinger, Stine technical agronomist for the eastern Corn Belt. “Several diseases, including SDS, and field stressors, like IDC, thrive in these conditions. There are other diseases and environmental stressors this weather pattern favors, but these two are the ones I’m most concerned about in soybeans.”
Early detection this season is key to understanding the extent of SDS and IDC pressure in your fields, but with limited in-season management options, the real value will be in what you do next.
“Using what you find this season will help you make smarter, more informed decisions heading into 2027,” says Kessinger. “Stine agronomists and sales reps are available to help guide you through the process.”
Here are some tips and information to assist your scouting efforts this season and planning for the next.
Watch for SDS
SDS is one of the most damaging soybean diseases in the U.S. Each year, millions of bushels are lost in soybean-producing states because of it.
Caused by the Fusarium pathogen, SDS can overwinter in crop residue and soil as spores, or chlamydospores. Soybean fields can be infected (or spores can reactivate) as soon as the seed is planted, but symptoms often take time to appear. The recent cool, wet conditions could increase infection risk this season, so growers should watch for foliar symptoms in late June and early July.
“It has been an almost perfect scenario for this disease to take hold,” says Kessinger. “It will likely not show up for another month, but the plant is already infected.”
One indicator of SDS is yellowing between leaf veins, which can progress into brown lesions and interveinal necrosis. Other indicators include stem discoloration, leaf cupping or curling, leaf detachment from the petioles, and soft, rotten roots.
Kessinger recommends that growers who suspect SDS dig up a few plants in the suspected area and split the stem lengthwise with a cutting utensil. SDS can often be confused for brown stem rot or red crown rot, so this step is important for proper diagnosis. If the pith is white, SDS may be present. If the pith is darker, it may be brown stem rot. If farmers are uncertain, they should consult a Stine agronomist or extension specialist.
If SDS is confirmed or suspected, the best way to get ahead of the disease is to consider SDS-tolerant soybean varieties for next year.
“At this point, if you have SDS in your fields, there’s not much you can do in-season but plan ahead for the next,” says Kessinger. “I remind growers that Stine has varieties that have tolerances to SDS and seed treatments that provide protection, but there’s not currently a 100% solution. Under high enough pressure, any variety can get SDS.”
A combination of SDS-tolerant varieties, seed treatments, tillage to break up the fungus leftover in crop residue and soil, rotation to a nonsusceptible crop, staggering planting dates, and controlling compaction is often the best strategy for combating this yield-robbing disease.
IDC scouting
This season’s growing environment has also been prime for IDC pressure.
“IDC is a hot topic right now, due in large part because of the cool, wet weather patterns,” says Tyler DuBay, Stine soybean technical agronomist.
IDC is exacerbated by crop stress and cool, wet growing environments, which make it harder for the plant to absorb soluble iron, leading to interveinal chlorosis. Growers who detect yellowing of leaves, especially on newly developed leaves in the first trifoliate, with green leaf veins should look further into a diagnosis. According to experts from the Crop Protection Network, while plants can grow out of IDC, they can be left stunted in certain situations, leading to yield loss.
This is why Stine agronomists are working to find IDC-tolerant soybean varieties in our product lineup. Leveraging drone technology in our research is accelerating these efforts.
Eyes in the sky
Drone technology is changing how agronomists and research and development teams identify and respond to IDC and SDS.
“With drones, we can bring new opportunities to leverage data and imaging to provide a broader picture of each field,” says DuBay. “For example, with IDC, we are flying drones to test for IDC scores, and we’re able to quantify data for customers about their fields to help generate actions for future seasons when it comes to the stressor.”
DuBay adds that the team is already collecting IDC imagery in our system this season, where we can see the differences between varieties and their performance.
For example, in the image below, green indicates strong IDC performance, while red signals high IDC pressure. This imagery and data are made possible by drones paired with John Deere-owned Sentera’s remote imaging solutions.
“Sentera’s platform provides us with more quantifiable data when it comes to IDC and SDS tolerance with our soybean varieties,” says DuBay. “It’s a bird’s-eye view of entire fields to supplement product research and our recommendations to farmers. We can also develop prescriptions to pair with customers' technology to ensure easy operation.”
When it comes to SDS, Stine is operating one of the most extensive SDS efficacy trials in the industry.
“We have the largest SDS efficacy trial to test most Stine brand products that could be exposed to SDS,” says DuBay. “Obtaining soybeans with high SDS tolerance will enable growers to ensure they will have a genetic yield advantage.”
To do this, drones are used in our plot program to assist with aerial crop imaging for SDS scoring. These efforts help evaluate low- and high-tolerance varieties, allowing us to refine ratings and giving farmers a better understanding of what to expect from Stine SDS-tolerant soybeans.
Combining drone technology with human expertise yields the best results. Our agronomists always recommend a sound agronomic plan for combating SDS and IDC — one that leverages drone technology to support our variety research but also relies on seed treatments as another critical line of defense. Identifying the best-performing varieties under SDS and IDC pressure is only part of the solution; pairing them with the right seed treatment package helps protect growers from the moment the seed enters the ground.
Seed treatments — the first line of defense
While most diseases appear midseason, prevention starts before the seed is planted. Seed treatments are a critical line of defense against fungal pathogens, such as Fusarium, the pathogen responsible for SDS.
Stine XP® seed treatments offer growers two custom-blend formulations: Stine XP-F&I and Stine XP Complete 2.0, which combat a broad spectrum of seedling diseases and insects.
For farmers seeking a solid fungicide and insecticide package, Stine XP-F&I is an excellent choice. This custom-blend seed treatment delivers broad-spectrum protection against Rhizoctonia solani, Fusarium, seed-borne Phomopsis, Pythium spp., Phytophthora spp. and Sclerotinia.
Growers facing elevated SDS pressure should consider Stine XP Complete 2.0. The formulation builds on the same base fungicides and insecticide as Stine XP-F&I but is enhanced with Heads Up® — a biological seed treatment for the suppression of SDS and white mold — and an increased rate of Thiabendazole 4L ST for added protection from SDS. It is also enhanced with AmpliFYR® biostimulant, which delivers bioactive compounds extracted from biochar to drive seedling growth above and below ground, supporting better crop establishment and higher yields.
In 2026, Stine is also partnering with Michlig Ag Solutions to evaluate Stine XP SureFlow in farmers’ fields and within our Product Development Plot (PDP) program. Stine XP SureFlow goes beyond the traditional seed treatment; it functions as a planter box lubricant, improving equipment efficiency and early-season crop vigor. It integrates macro- and micronutrients to promote early root development and uniform emergence while also introducing humic and fulvic acids to enhance nutrient availability and soil interaction in the seed zone.
“The results of Stine XP SureFlow have been nothing short of impressive, and we hope it will become an effective crop management tool to enhance products further in the future,” says Kessinger.
As the season progresses and more data comes in from our drone imaging and plot programs, the picture will become even clearer. Our team will be there every step of the way to assist growers throughout the season, whether they are dealing with SDS, IDC or other field stressors.
To learn more about midseason crop scouting for diseases such as SDS and IDC and how Stine seed treatments and drone technology can support a comprehensive crop plan, reach out to your local Stine independent sales representative.