Bacterial leaf streak of corn: New disease confirmed in the U.S.

If you suspect bacterial leaf streak (Xanthomonas vasicola pv. vasculorum) in your Michigan corn, send samples to MSU Diagnostic Services.

Bacterial leaf streak on corn. Note wavy margins of the bacterial leaf streak lesions. Photo: Tamra Jackson-Ziems, University of Nebraska-Lincoln.

Bacterial leaf streak on corn. Note wavy margins of the bacterial leaf streak lesions. Photo: Tamra Jackson-Ziems, University of Nebraska-Lincoln.

Bacterial leaf streak of corn is caused by the bacterial pathogen Xanthomonas vasicola pv. vasculorum. The disease was first reported in the Republic of South Africa in 1949. The disease was confirmed on Aug. 26, 2016, in Nebraska, Colorado, Illinois, Iowa and Kansas. It appears as though this disease is widely distributed throughout the Corn Belt. However, no research data is available to predict potential impact of this disease on yield.

Bacterial leaf streak symptoms look similar to other diseases, particularly the fungal disease gray leaf spot. Gray leaf spot produces lesions with straight margins along the veins of the leaf, unlike bacterial leaf streak, which produces wavy margins (see photos). Symptoms of the disease have been seen as early as mid-June in Nebraska. Diagnosis can be difficult, so a sample should be submitted to Michigan State University Diagnostic Services or the Chilvers Field Crop Pathology lab.

As the disease is caused by a bacterial pathogen, fungicides will not control this disease. Although bactericides are labelled for use on corn, their practicality and potential efficacy is limited. Crop rotation and debris management may be helpful. Additional research is needed and is ongoing in several states.

MSU Extension needs your help to determine if this pathogen is present in Michigan. If you suspect bacterial leaf streak, please submit a sample to MSU Diagnostic Services or the Chilvers Field Crop Pathology lab.

Bacterial leaf spot on corn

Bacterial leaf streak on corn. Note the wavy margins of the bacterial leaf streak lesions. Photo: Tamra Jackson-Ziems, University of Nebraska-Lincoln.

Gray leaf spot on corn

Gray leaf spot on corn. Note the straight margins of the gray leaf spot lesions as defined by the leaf veins. Photo: Martin Chilvers, MSU.

Additional resources:

Dr. Chilver’s work is funded in part by MSU’s AgBioResearch.

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