부산대학교 도서관

A survey of Phytophthora diseases of cucurbit crops in Taiwan was conducted from 1980 to 2015 and Phytophthora species were detected in 62 cucurbit fields. Analysis of morphological characteristics and RNA Internal Transcription DNA Sequence (ITS1-5.8S rDNA-ITS2) of these isolates revealed that Phytophthora melonis and Phytophthora capsici were two predominant species found in Taiwan cucurbit fields. Analysis of 100 P. melonis isolates obtained from 36 sites revealed that 44 isolates were A^1 and the remaining isolates were A^2. P. melonis was primarily isolated from diseased cucumber (Cucumis sativus), wax gourd (Benincasa hispida), bottle gourd (Lagenaria siceraria), melon (Cucumis melo), and watermelon (Citrullus vulgaris). Analysis of P. capsici 77 isolates collected from 26 fields revealed that 27 isolates were A^1 and 50 isolates were A^2. P. capsici was isolated from cucumber, wax gourd, Chinese squash (Cucurbita moschata), ornamental gourd (Cucurbita pepo var. ovifera), bottle gourd, melon and watermelon. Phytophthora melonis mainly attacked the basal stems, fruits and young seedlings of cucumber and the fruits of other cucurbit plants in the fields. In contrast, P. capsici mainly induced fruit rot of the infected plants, but sometimes it also caused seedling damping-off and basal stem rot. All Phytophthora isolates collected from cucurbit belonged to the typical types of P. melonis or P. capsici. Pathogenicity assays revealed that the pathogens caused symptoms resemble those found in the fields and the same pathogen could be reisolated from all artificially infected tissues. Pathogenicity tests showed that both Phytophthora species were highly virulent to the seedlings of cucumber, wax gourd, Chinese squash, bottle gourd, melon and watermelon, but not to bitter melon (Momordica charantia) and luffa (Luffa cylindrica). In addition, P. capsici but not P. melonis isolated from cucurbit plants was highly virulent to sweet pepper. To our knowledge, this is the first report of Phytophthora spp. causing diseases on wax gourd, Chinese squash and bottle gourd in Taiwan.