Notes from the combine: soybean successes and failures this season

Soybean harvest is well on its way to completion in most areas — 85% of soybeans have been harvested across 18 states — so now is a good time to take note to adjust management concerns in 2024. 

Soybean yields across the Corn Belt have been varied but for the most part many farmers have been pleasantly surprised. Brad Miller, a Bayer technical agronomist in Ohio, has seen yields averaging about 65 bu/acre. “Most people are surprised because we had all that early drought in the spring through May and June. We finally started getting rains in July and August, and I think that was what really made the crop.”

Steve Johnsen, a Bayer agronomist in Nebraska, shared that yields are down for soybeans. “Compared to average, I’d say we’re down. We are not seeing the yields meeting potential in the dryland acres. Even in the irrigated acres, we just struggled to keep up with crop demands late so we’re not achieving the normal yield potential.”

Take note of issues for future management

White mold made an appearance in soybean fields late this summer. “White mold took people by surprise because we were really dry in May and June, and white mold requires moisture in the canopy. The rains that we received in July and August, which we needed for the crop, accelerated crop growth and allowed for disease development in the canopy. As we started walking fields in August and September, we saw white mold showing up,” Miller said.

“We’ve seen movement of white mold tracking to the south here in Nebraska,” Johnsen said. “We should keep an eye on white mold in soybeans next year and be prepared to scout and manage it in 2025 when we come back to those fields that we know experienced issues this year.” 

For growers who had issues with white mold this year, management for next year includes soybean variety selection and fungicide applications in the reproductive stages. 

“The best management for white mold is to choose a variety with good tolerance but secondly, we’re seeing significant advantages to spraying two times with Delaro or Delaro Complete fungicide. The first application should be timed at the R1 growth stage and then come back with the second application at R3 or R4,” recommends Miller.

Some areas of Illinois experienced root rot in soybeans after the heavy rains in late June and early July. Stephanie Porter, outreach agronomist for Illinois Soybean Association, recommends that growers take note of issues and make plans to manage in future years. “In some cases, farmers can seek out varieties with good tolerance to phytophthora root rot but I fear that we could be starting to see a shift of phytophthora species overcoming some resistance currently used in soybean varieties.” 

Parts of Nebraska also suffered from some standability issues brought about by the Dectes stem borer. Milder winters have contributed to soybean stem borer survivability, as has the shift to no-till acres where residue is no longer being buried. One management strategy is to shift to a fuller-season soybean variety that allows more time for harvest before lodging is likely. “Early relative maturity varieties tend to be more susceptible so we try to stretch it out with fuller-season soybeans that don’t senesce quite as early,” says Johnsen.

Illinois Soybean Association has funded a multiyear research project to better understand and manage soybean stem pests and diseases such as phytophthora, red crown rot, Dectes stem borer, and soybean gall midge. 

“Red crown rot has become a major issue in parts of western Illinois and continues to be discovered across the state. We are still learning about this disease and have prioritized research in the coming years. We have a lot of work to do,” shares Porter.