Last growing season (2016) a new corn disease called bacterial leaf streak (BLS) was confirmed in Illinois for the first time in DeKalb County. Symptoms of BLS include narrow yellow, tan, brown or orange lesions with wavy margins that occur between and along leaf veins (Figure).
While symptoms of this disease were observed in Nebraska as early as 2014, it took scientists several years to identify the pathogen that caused the symptoms. In 2016 the disease was found in nine states and the cause of BLS was identified - a bacterial pathogen called Xanthomonas vasicola. Field-, seed-, pop- and sweetcorn are all susceptible to this bacterial pathogen.
As symptoms of BLS can be observed as early as the seventh leaf growth stage, now is the time to become familiar with how to identify this disease in the field. Proper identification is of particular importance as similar to other bacterial diseases like Stewart's wilt and Goss's wilt, foliar fungicides are ineffective. Foliar fungicides can provide protection against infection by fungal and not bacterial pathogens.
A nice digital fact sheet was produced by University plant pathologists detailing what is currently known about identification and management of BLS. It is available for viewing and for download at the Crop Protection Network website.