First Report of Sorghum Zonate Leaf Spot caused by Gloeocercospora sorghi in China

Sorghum [Sorghum bicolor (L.) Moench] is not only an important food crop, but also used as forage, brewing and industrial raw materials in China. In October 2016, large purple-red, irregular lesions were observed on leaves of several sorghum varieties in Chaoyang city of Liaoning Province, China. The most serious symptom occurred on sorghum variety “Jiza140” and the yield losses was 30% approximately. Lesions on leaves were purple-red or dark brown color, nearly circular or irregular with 2-8 very obvious rings. Lesions occur along the leaf margin or near the midrib with semi oval. In severe cases, lesions join to cover a large proportion of the leaf surface. To identify the pathogen, symptomatic leaf lesions were collected from fields and cut into small pieces, surface-sterilized in 75% ethanol for 5 s, then disinfested in 2% NaOCl for 2 min and rinsed with sterilized water. The small pieces of leaves containing lesions were placed on water agar (WA) at 25°C to allow sporulation. After incubation for 4-5...