First Report of Leaf Spot in Water Spinach Caused by Ectophoma multirostrata

Gyo-Bin  Lee1   Hong-Sik  Shim1   Weon-Dae  Cho1   Wan-Gyu  Kim1,*   

1Global Agro-Consulting Corporation, Suwon 16614, Korea

Abstract

Leaf spot symptoms were observed in water spinach (Ipomoea aquatica) plants growing in fields in Ansan and Hongseong, Korea, during disease surveys in 2019 and 2020. The symptoms appeared as brown to dark brown circular or irregular spots on the leaves of the plants. The disease incidence on the plant leaves in the fields investigated at the two locations ranged from 1% to 20%. Five single-spore isolates of Phoma sp. were obtained from lesions of the diseased leaves. All the isolates were identified as Ectophoma multirostrata based on their cultural and morphological characteristics, as well as molecular analysis. Two isolates of E. multirostrata were tested for pathogenicity on water spinach leaves using artificial inoculation. The tested isolates caused leaf spot symptoms in the inoculated plants. These symptoms were similar to those observed in plants from the investigated fields. To our knowledge, this is the first report of E. multirostrata causing leaf spot in water spinach.

Figures & Tables

Fig. 1. Leaf spot symptoms in water spinach plants. A and B: Symptoms observed in the investigated fields. C: Symptoms induced by artificial inoculation test with an isolate of Ectophoma multirostrata. D:A non-inoculated plant (control).