New Bacterial Leaf Disease is Confirmed in One Illinois Corn Field

[September 19, 2016]    CHAMPAIGN - In a recent survey of approximately 340 corn fields in 68 Illinois counties, bacterial leaf streak was confirmed in only one county, according to Kelly Estes, Cooperative Agricultural Pest Survey (CAPS) coordinator, Illinois Natural History Survey (INHS), Prairie Research Institute, University of Illinois.

INHS, along with the University of Illinois Extension, Illinois Department of Agriculture, and the U.S. Department of Agriculture’s Plant Health Inspection Service (USDA APHIS), surveyed corn fields after the disease was confirmed in Nebraska in July.

Bacterial leaf streak was found in DeKalb County in northeastern Illinois and also was confirmed in Iowa and seven other states as part of this survey.

The symptoms of bacterial leaf streak are similar to the fungal disease gray leaf spot (GLS). The bacterium produces irregular, narrow brown to orange stripes between leaf veins that can be 1 inch to several inches long. GLS lesions tend to be shorter and more rectangular in shape.
Bacterial leaf streak is spread by wind, rain, and irrigation, and warm temperatures exacerbate the disease. Little is known about the biology of the bacterium, but the USDA indicates that it doesn’t pose a risk, and there is no evidence of negative effects to corn yields or quality in the 2016 season. Fungicides are not expected to control or suppress the disease.

Bacterial leaf streak will be on the list of diseases to survey as part of next year’s CAPS program, Estes said.

If you suspect bacterial leaf streak, submit a sample to the University of Illinois Plant Clinic http://web.extension.illinois.edu/plantclinic/

About the Prairie Research Institute: The Prairie Research Institute (PRI) at the University of Illinois at Urbana-Champaign comprises the Illinois Natural History Survey, Illinois State Archaeological Survey, Illinois State Geological Survey, Illinois State Water Survey, and Illinois Sustainable Technology Center. PRI provides objective natural and cultural resource expertise, data, research, service, and solutions for decision making, the stewardship of Illinois’ resources, and the public good. www.prairie.illinois.edu

[Lisa A. Sheppard]