In the central part of the state, the soybeans that have so far survived the extreme temperatures and drought are now showing symptoms of charcoal rot.
Plant Diagnostic Clinic and IPM coordinator Suzanne Bissonnette says that, in the past 2 weeks, the University of Illinois Plant Clinic (http://web.extension.illinois.edu/plantclinic/) has diagnosed the disease in several samples.
"We have had greater than a 95% isolation rate from the declining soybeans even when the characteristic signs and symptoms of the disease were not yet present," she adds. "Our findings are distressing news for producers with fields that are already under extreme environmental stress."
Charcoal rot is caused by the fungus Macrophomina phaseolina. It has a host range of over 500 crop and weed species, including corn and wheat.
Unlike most other fungal diseases, which infect the crop when there is moisture present and temperatures are warm, it is most prevalent when the weather is dry and blazing hot.