An Old Disease Makes A Return Appearance: Late Season Diseases

Sep 11, 2013

Anne Dorrance, Harold Watters, CPAg/CCA

An old disease makes a return appearance: Late Season Diseases

Stem Canker (Left) and Phytophthora Stem Rot (Right)

Stem canker has been identified in a few fields in Ohio as well as neighboring states this year. The key symptom is a dieback of the plant. A canker can be found, for northern stem canker at the 3rd to 4th node. It is reddish brown and can surround the stem or go up as a streak along one side of the plant. This can be separated from Phytophthora stem canker as in Phytophthora the base of the plant and roots are decayed while in stem canker the roots and base of the plant are healthy. Stem canker can be caused by one of two different fungi: Diaporthe phaseolorum var. caulivora (northern) and Diaporthe phaseolorum var. meridonalis (southern). Infections by both fungi occur during the vegetative stages during rainy weather, which we had plenty of this year. Seed infection can also contribute to this disease as well as heavy soybean residue. Host resistance is the key management strategy and in fact it has been a long time (> 10 years) since we have had fields with reports of high incidence.

Source : osu.edu

Video: Wisconsin Corn and Soybean Weed Management Updates and Considerations for 2026 and Beyond

Dr. Rodrigo Werle, associate professor and extension weed scientist, UW–Madison, shares the latest updates and future considerations for corn and soybean weed management in Wisconsin. This presentation covers herbicide resistance trends in waterhemp, including newly confirmed cases of HPPD and S-metolachlor resistance, and emphasizes the importance of residual herbicides and strategic tank mixes for consistent control. Rodrigo also introduces upcoming technologies like Vyconic soybeans and new herbicide products, discusses integrated weed management strategies such as planting green with cover crops, and highlights practical recommendations for 2026 and beyond.

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