Studies on the Complex Disease Caused by Root-knot Nematode and Fusarium Wilt Fungus in Tomato Seedlings : I. Development of Wilt Symptom and Difference in Disease Incidence in Tomato Varieties

摘要

Studies on the Complex Disease Caused by Root-knot Nematode and Fusarium Wilt Fungus in Tomato Seedlings. I. Development of Wilt Symptom and Difference in Disease Incidence in Tomato Varieties. T. KAWAMURA and K. HIRANO. Faculty of Horticulture, Chiba University, Matsudo, Japan. Tech. Bull. Fac. Hort. Chiba Univ., No.15: 7〜19, 1967. The authors studied on the complex disease of tomato seedlings caused by both root-knot nematode, Meloidogyne incognita (KOFOID and WHITE) CHITWOOD and Fusarium wilt fungus, Fusarium oxysporum f. lycopersici (SACC.) SNYDER et HANSEN. There were varietal differences in the development of wilt symptoms in tomato seedlings. In u22Matsudo-Ponderosau22 variety, susceptible to both Meloidogyne and Fusarium, the wilt symptoms in plants inoculated with both pathogens developed significantly greater than those with Fusarium alone. However, in u22Okitsu No.1u22, susceptible to Meloidogyne and resistant to Fusarium, and u22Anahuu22, resistant to both pathogens, the wilt symptoms did not appear in plants of these varieties even when inoculated with both pathogens. The severest development of wilt symptoms in u22Matsudo-Ponderosau22 occurred among plants inoculated with two pathogens simultaneously and this was intensified by increasing nematode quantity inoculated. The degree of wilt incidence of tomato seedlings varied with the inoculation order of nematodes and fungi, inoculating alternately at 16 dayintervals; the wilt symptoms in plants inoculated with nematodes after fungus inoculation developed greater than those in plants inoculated with nematodes first. The plants which showed the wilting rapidly after nematode-fungus inoculation interrupted the galling of roots, and gall index of these plants decreased slightly. Whole symptoms associated with the complex disease in tomato seedlings appeared in the galls on roots and the wilts on stems and leaves, and they were especially extended by wilting only. Therefore, the functional nature of the complex disease caused by Meloidogyne and Fusarium, which appeared