First Report of Curvularia Leaf Spot of Corn, Caused by Curvularia lunata, in the United States

Abstract

During the summer of 2017, corn (Zea mays L.) in production areas throughout Louisiana exhibited symptoms similar to eyespot, caused by Kabatiella zeae (Narita & Y. Hirats). Symptoms included round to oval, light tan to light brown lesions (0.5 to 2.0-mm diameter) with reddish-brown margins often with chlorotic halos in the mid to upper canopy of corn at the brown silk stage. The disease was not severe enough to warrant management; however, it was a concern to corn producers. Symptomatic leaves were obtained from diseased corn, lesion margins were disinfested, and the suspected pathogen was isolated and tentatively identified as Curvularia lunata. Koch’s postulates were completed by inoculating V4 to V5 stage corn plants with a spore suspension and subjecting plants to a 16-h dew period at 25°C, observing symptomology, reisolating the pathogen, and identification via molecular analysis. To our knowledge this is the first report of the disease in Louisiana and the United States.