Occurrence and analysis of Apple Blotch-like symptoms on apple leaves

Abstract

Apple blotch-like symptoms (ABLS) were observed on ‘Fuji’ apple leaves in Cheongsong, Gunwi and Yeongcheon apple orchards located in Gyeongbuk Province during 2010-2014. Characteristics of ABLS were yellowing, brown spots on leaves, and defoliation, similar to apple blotch diseased (ABD) leaves, which are infected with Marssonina coronaria. It is difficult to differentiate by eye between ABLS and ABD, which has led to misdiagnosis and overuse of fungicide11. The present study was conducted to investigate the cause of ABLS using stereomicroscopy, culture isolation, c11-sectional analysis of leaves, and PCR. No acervuli were found on the surface of ABLS leaves and no growth was obsearon potato dextrose agar (PDA) plates in culture. Furthermore, cross-sectional analysis revealed distinct from ABD.