Identification of Grovesinia moricola Causing Zonate Leaf Spots on Lespedeza cyrtobotryain Korea

Ji-Hyun  Park1   Bok-Nam  Jung1   Sang-Hyun Lee1   Hyeon-Dong Shin2,*   

1Division of Forest Insect Pests and Diseases, National Institute of Forest Science, Seoul 02455, Korea
2Division of Environmental Science and Ecological Engineering, Korea University, Seoul 02841, Korea

Abstract

In September 2017, a heavy damage by premature defoliation with the zonate leaf spots was observed in several shrubs of Lespedeza cyrtobotryagrowing at Mt. Obongsan in Chuncheon, Korea. Numerous cone-shaped, white sporophores of a fungus were observed on lesions of the abaxial leaf surface. A similar fungus was isolated in September 2019 from the leaves of L. cyrtobotrya growing at Mt. Taegisan in Hoengseong, Korea. The morphological characteristics of the sporophores were consistent with those of Grovesinia moricola. The species identification was confirmed by sequencing the internal transcribed spacer (ITS) region of the ribosomal DNA from the two isolates (KACC48417 and KACC48934). The fungal pathogenicity was determined by an artificial inoculation in conditions of relative humidity and temperature of 100% and 15±2℃, respectively. This is the first report of association of G. moricola with L. cyrtobotrya in Korea.

Figures & Tables

Fig. 1. Zonate leaf spots of infected with . A, heavy infection in September, 2019; B, C, close-up of symptoms; D, a sporophore formed on the abaxial surface of a leaf lesion; E, five-day-old colony of on potato dextrose agar (PDA); F, three-week-old colony of G. moricola with formation of sclereotia (arrows) on PDA; G, close-up of sclerotia (arrows); H, a leaf showing small lesions 3 days after artificial inoculation; I, appearance of many sporophores on a leaf lesion 2 weeks after artificial inoculation; J, close-up of sporophores on a leaf lesion.