August 14, 2009

White mold infects Ohio soybeans

Damp weather and cool temperatures have caused a major outbreak of white mold on soybeans in Ohio for the first time in almost a decade, researchers said.

The mold, so far, has been limited to fields in southern and northeastern Ohio, said Anne Dorrance, an Ohio State University Extension plant pathologist.

White mold, or Sclerotinia stem rot, spreads by infecting decaying soybean stem tissue or blossoms before they fully flower. The fungus produces oxalic acid, which kills the plant tissue, Dorrance said.

The base of dying plants will have large fluffy white regions and the stem will be bleached white with large, copious amounts of mycelia growth, Dorrance said.

Little can be done to stop the infection and plant scientists do not recommend applying fungicides.

We don't want the fungus building up tolerance to that fungicide, she said. With the damage done so close to flowering, growers will just have to deal with it.