Abstract
Many isolates belonging to the genus Phomopsis were obtained from the concave rot of melon fruit, Cucumis melo, a new postharvest disease. They were divided into four groups of A, B, C and D according to their cultural characters on PSA. Several representative isolates selected from each type of isolates showed clear pathogenicity to melon fruits. Morphologically, isolates were divided into two groups; one having shorter β-conidia and containing colony groups of A and B, and the other having longer β-conidia and containing colony groups C and D. Some isolates of the former group produced perithecial stage on PSA and also on water agar plate containing a fragment of melon fruit. A new variety of Diaporthe melonis Beraha et O'Brien, D. melonis var, brevistylospora Kobayashi et Ohsawa was proposed for the fungus. Although the isolates of the latter did not produce any perithecia on artificial media mentioned above, these were identified as the conidial stage of Diaporthe melonis Beraha et O'Brien var. melonis, Phomopsis cucurbitae McKeen sensu Behara et O'Brien.
