First report of powdery mildew caused by Erysiphe aquilegiae var. ranunculi on Catharanthus roseus in Korea.
In September 2015, individuals of pot-grown C. roseus were found infected with a powdery mildew in a nursery in Seoul, Korea. Numerous chasmothecia were formed on the lesions by November. Based on morphological characteristics, sequence analysis of the internal transcribed spacer regions and pathogenicity tests, the causal agent was identified as Erysiphe aquilegiae var. ranunculi. Powdery mildews of C. roseus have been recorded as Leveillula taurica, Oidium sp., and Erysiphe sp. (Amano 1986; Watanabe and Sato 2009; Farr and Rossman 2016). Liberato and Cunnington (2006) reported E. aquilegiae as a powdery mildew of C. roseus, and Braun and Cook (2012) listed the fungus as E. aquilegiae var. ranunculi. This is thought to be the first report of powdery mildew caused by E. aquilegiae var. ranunculi on C. roseus in Korea.