Occurrence of Dry Rot on Cymbidium Orchids Caused by Fusarium spp.in Korea

Lee, Byung Dae; Kim, Wan Gyu; Cho, Weon Dae; Sung, Jae Mo

The Plant Pathology Journal 2002;18(3):156-160.
Published online June 30, 2002.

Occurrence of Dry Rot on Cymbidium Orchids Caused by Fusarium spp.in Korea

Byung Dae Lee, Wan Gyu Kim, Weon Dae Cho, Jae Mo Sung

Abstract

Cymbidium orchids with blight and rot symptoms were collected, and a total of 63 isolates of Fusarium spp. was obtained from pseudobulbs, roots, and leaves of the diseased plants. The isolates were identified based on their morphological characteristics. Out of the 63 isolates of Fusarium spp., 51 isolates were identified as F. oxysporum, 10 isolates as F. solani, and the rest as F. proliferatum. F. oxysporum was isolated from all the Cymbidium spp., while F. solani and F. proliferatum were isolated only from Cymbidium ensifolium and C. ginatum, respectively. Isolates of the three Fusarium spp. were tested for pathogenicity to their hosts by artificial inoculation. The strongly pathogenic isolates of Fusarium spp. induced severe dry rot of pseudobulbs and roots of the host plants. The symptoms progressed up to the basal part of the leaves, which later caused blight of the entire plant. The dry rot symptoms induced on the plants by artificial inoculation with the isolates of Fusarium spp. were similar to those observed in the growers` greenhouses. This is the first report of dry rot of Cymbidium spp. caused by F. oxysporum, F. solani, and F. proliferatum in Korea.

Key Words: Cymbidium spp., dry rot, Fusarium oxysporum, F. solani, F. proliferatum, orchid