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Posted 25 November 2013. PMN Crop News.

DuPont Pioneer Introduces New Charcoal Rot Scoring System

Growers can select soybean varieties depending on expected disease pressure

Source: DuPont Pioneer Press Release.

Des Moines, Iowa (November 6, 2013)--DuPont Pioneer customers dealing with charcoal rot will have a new opportunity in 2014 to make Pioneer brand soybean variety selections with enhanced charcoal rot tolerance scores. These scores are backed with solid research information about tolerance to the fungus that causes charcoal rot.


This widespread disease normally favors hot, dry conditions and is made worse when drought occurs, causing stress to the plant. It can also occur in fields that experience optimal infection conditions but don't show significant drought stress through the season. These varied conditions show the need for a score to rate tolerance to the disease independent of field conditions.

"Just as we provide scores for SCN resistance or SDS tolerance on our soybean products, our current research allows us to provide dependable charcoal rot tolerance scoring for soybean varieties," explains Les Kuhlman, DuPont Pioneer senior research scientist based in Lawrence, Kan., who leads the research team studying the drought-related disease.

The introduction of this new score allows growers to select the degree of tolerance they need in a field, based on the expected level of charcoal rot pressure. Scores are based on Pioneer research observations of the comparative ability to tolerate the infection of the charcoal rot pathogen among various soybean varieties. The scores range from 1 to 9 on the Pioneer scale, with 1 being susceptible and 9 being resistant. This score replaces the older CRDC (charcoal rot drought complex) score seen on previous varieties.

"Each grower has a different situation when it comes to charcoal rot," says Kuhlman. "Some experience it with drought conditions and some do not, and now they can select soybean varieties based on their particular situation, thanks to these tolerance scores."

While selecting soybean varieties with a charcoal rot tolerance score is very convenient, an integrated management approach is vital for reducing microsclerotia (a diagnostic symptom of charcoal rot) levels in the soil and stresses to the crop.

Management practices to help limit charcoal rot include:

Rotating to corn or wheat

Scouting fields for charcoal rot symptoms to determine which have infection

Irrigating to help reduce drought stress

Avoiding excessive seeding rates and maintaining adequate soil fertility levels

Controlling weeds to reduce alternate hosts and competition for available soil moisture

Jerry Harrington
800-247-6803 ext. 56908