Microscopic observation and pathogenicity determination of common molds on postharvested longan fruit cv. Daw
Pitchayaporn suwanakood; Vicha sardsud; Somsiri sangchote and Uraporn sardsud
20th Biennial Conference of the ASIAN ASSOCIATION FOR BIOLOGY EDUCATION “Roles of Modern Technologies in Biology Education”. Chiang Mai University. Chiang Mai, Thailand. 27-30 December 2004. Page 30.
2004
บทคัดย่อ
Microscopic observation and pathogenicity determination of common molds on postharvested longan fruit cv. Daw
Longan (Dimocarpus longan Lour. cv. Daw) is among one of the important exported fruits in Thailand. This crop confronting with a severe postharvest fungal rot disease problem. Study on the surface appearance using stereo microscopy showed that the fruit skin rough and uneven. Under scanning electron microscope, the surface of longan fruit consisted of scale and epidermal hair, in some areas the remnant of cuticle could be observed. The filamentous fungi were observed from fruit surface. Many genera of fungi were isolated from healthy fruit skin of harvested longans by tissue transplanting method, such as, Aspergillus, Cladosporium, Colletotrichum, Fusarium, Lasiodiplodia, Mucor, Penicillium, Pestalotiopsis, Phomopsis, Rhizopus, Trichoderma, Verticillium and 7 genera unidentified. Each of the fungal isolate was inoculated onto the pericarp of the fruit for pathogenicity determination. Pathogenic ability showed that the common mold found on the fruit skin, Lasiodiplodia and Pestalotiopsis caused the most severe symptoms and rot the fruit rapidly, respectively. The most virulent isolate was identified as Lasiodiplodia theobromae based on morphological characteristics and DNA sequencing.