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Scout Soybeans For Water-Borne Diseases

No-tillers should watch and scout their soybeans for water-borne diseases that may have cropped up during recent heavy rains, says Ann Dorrance, an Ohio State University Extension plant pathologist.

Saturated soils and ponding conditions are ideal for the development of diseases such as pythium seed rot, phytophthora root and stem rot, fusarium root rot and rhizoctonia stem rot, says Dorrance.

“Right now, because of the cooler soils, the crop is most susceptible to pythium seed rot and damping-off,” she says. “We’ve been pulling some pythium from our plots already.”

No-tillers should scout their fields for classic signs of damage from water molds and other soil-resident pathogens, she advises.

“When scouting fields, what you’ll see are big blank spaces where seedlings have died and plants haven’t emerged, or plants will come up and will damp-off, meaning that they turn brown and die,” Dorrance says.

 “If a dead plant has a red canker at the base, it’s probably rhizoctonia. If it’s brown and soft, it’s pythium or phytophthora. If it’s pink, then it’s probably fusarium.”

In situations where no-tillers must replant, wait until the soil is completely dry for a few days before planting new seed, she says.

“Pathogens tend to go dormant under dry conditions and they have to be re-wetted to get started back up again,” Dorrance says. “You don’t want to re-plant quickly into these fields when the pathogens are active. You may end up having to re-plant two or three times.”

She highly recommends no-tillers use seed treatments to protect the seedlings.

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