First report of sooty blotch on Gynura bicolor caused by Zasmidium gynurae in Japan

Abstract

Sooty blotch was found on Gynura bicolor seedlings in Okinawa Prefecture in 2017. Fungal-like isolates, mainly obtained from the lower leaves, caused similar symptoms on plants sprayed with individual isolates, which were identified as Zasmidium gynurae based on morphological characteristics and sequences of rDNA ITS regions. This is the first report of a disease of G. bicolor caused by Z. gynurae in Japan, and we propose the Japanese name “susuhan-byou” (sooty blotch) of Gynura bicolor.