Pathogenicity of Fusarium causing wilts on Cucurbitaceous plants was examined. Cucurbita ficifolia and C. maxima were attacked by Fusarium oxysporum f. sp. lagenariae, but not by F. oxysporum f. sp. melonis, f. sp. cucumerinum, f. sp. niveum and f. sp. luffae. But C. ficifolia was infected with F. oxysporum f. sp. melonis without external symptom, because the pathogen was isolated in a high rate from the hypocotyl tissues with browned vascular bundles. Therefore it was considered that C. ficifolia infected with F. oxysporum f. sp. melonis might wilt acutely under bad conditions. On the other hand, neither symptom nor symptomless infection by the above five pathogens was recognized in C. moschata, C. pepo and C. maxima×C. moschata.
The virus isolated from Iceland poppy showing mosaic symptoms was identified as turnip mosaic virus based on host range, symptoms, transmission mode, particle morphology and serological relationships. The virus infected 15 plant species of 8 families among 25 species of 9 families tested, and was transmitted by aphid in a nonpersistent manner. Virus particles were filamentous flexuous, 760-770nm in length. The virus showed close serological relationships with turnip mosaic virus. Stabilities in crude sap were 55-60°C for 10 min, 10-4-10-5 and 3-5 days at room temperature.