Battle for the Belt: Season 3, Episode 24: Sudden Death Syndrome vs Red Crown Rot

Season 3, Episode 23 of Battle for the Belt is now available: https://www.youtube.com/watch?v=vPUcULGy-h8

At this stage of the growing season, soybean fields may commonly exhibit foliar yellowing. While such symptoms can be associated with the onset of physiological maturity, they may also indicate the presence of disease. Therefore, regular field scouting remains a critical practice for accurate diagnosis.

One of the most frequently observed diseases during this period is Sudden Death Syndrome (SDS), which produces characteristic foliar interveinal chlorosis and necrosis (Figure 1). Recently, Red Crown Rot (RCR) has been confirmed in Ohio (Figure 2). This is of particular concern because the foliar symptoms of RCR are nearly indistinguishable from those of SDS, complicating field-level identification. To correctly differentiate between these two pathogens, root and crown examinations are required. In cases of red crown rot, the basal stem and crown tissues typically exhibit a distinct reddish to orange discoloration, which serves as a diagnostic feature of the disease. Read and learn more about red crown rot here.

Remember, when scouting your soybean field and if you identify red crown rot symptoms you should submit whole soybean plants with their root systems to the CFAES Soybean Pathology and Nematology Laboratory. Address samples to Horacio Lopez-Nicora, 110 Kottman Hall, 2021 Coffey Road, Columbus, OH 43210. Detailed instructions for sample submission are provided here.

What’s happening in the field?

 Drought conditions continue to be present and expand across the state, with very little rainfall occurring in recent weeks (Figure 3). As a result, several counties went from D0 (abnormally dry) to D1 level (moderate drought).

Many of our corn and soybean plants across planting dates are now in critical grain-filling stages, which can be sensitive to drought stress. In corn, drought during these stages can lead to premature death of leaf tissue, shortened grain-fill periods, kernel abortion, and reduced kernel weight compared to crops under more favorable moisture conditions. When drought occurs during the later reproductive stages, specifically R4 (dough) and R5 (dent), it often results in lighter kernels and can cause premature physiological maturity.

Soybeans are generally more resilient than corn under drought conditions, but prolonged dryness during pod set and seed fill still presents risks. When moisture is limited during these stages, the plant’s ability to compensate is reduced. This typically results in fewer seeds per pod, smaller seed size, and earlier maturity. Similar to corn, drought shortens the grain-filling period, and the greatest yield losses in soybeans are usually seen when drought occurs between the R4 (full pod) and R6 (full seed) stages.

 Field observations show that crops are continuing to progress steadily toward maturity. At the Western location, corn from planting date one has dried down quite a bit and is the first to reach the R6 stage, which marks physiological maturity (Figure 4). Corn at the Northwest and Wooster sites is not far behind, as it continues to dry down. In soybean, planting dates one through four have reached the R6 stage, full seed. These plants will enter R7 (begin maturity), once at least one pod on the main stem has turned brown or tan. For further information regarding weather summaries and crop growth stages, see Table 1.

Keep following the ‘Battle for the Belt’ this growing season to learn more and get further updates! You can find the full video playlist of Battle for the Belt on the Ohio State Agronomy YouTube channel.