First report of Alternaria alternata causing leaf spot of Pinellia ternata in China.
From the mid-June to mid-July of 2015, 20 to 35% of Pinellia ternata plants displayed a severe foliar disease in a cultivated field in Xihe County, Longnan City, Gansu Province, China, at an altitude of 1,770 m. The symptoms of the disease initially appeared as small circular to irregular spots, yellow to brown in color. As the disease progressed, some spots gradually coalesced, forming large necrotic puce patches. Margins of leaves curled inwards to upper surfaces or wilt. Symptoms were widespread during the rainy season from July to August. Based on morphological characteristics, DNA sequence analysis and pathogenicity tests, the causal agent was identified as Alternaria alternata. This is thought to be the first report of A. alternata causing leaf spot of P. ternata in China, causing yield losses of at least 20%.