First report of castor leaf spot caused by Cladosporium tenuissimum in Zhanjiang, China.
Ricinus communis (castor) is an important oil crop. Leaf spots on castor with disease incidence of ∼20.5% have been observed in ∼1 800 plants in the field (0.66 ha) located in Zhanjiang (Guangdong, China) since 2016. Early symptoms appeared on affected leaves as light brown or gray necrotic spots. Successively, a muold appeared on both sides of the spots. The spots were irregular in shape and increased in size and coalesced. Seven samples of symptomatic leaves were collected in the field. Based on morphological characteristics, sequence analysis of the rDNA internal transcribed spacer region and a pathogenicity test, the causal agent was identified as C. tenuissimum. It has been reported that C. tenuissimum caused leaf spot of banana and leaf blight watermelon. This is thought to be the first report of C. tenuissimum causing leaf spot in castor.