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Disease Note.

Race 2 of Fusarium oxysporum f. sp. melonis New to Israel. D. Netzer, ARO, The Volcani Center, Bet Dagan 50-250, Israel. C. Weintall, ARO, The Volcani Center, Bet Dagan 50-250, Israel. Plant Dis. 73:183. Accepted for publication 10 August 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0183B.

During summer 1987, within a commercial planting of muskmelons (Cucumis melo L. var. reticulatus Ser.) in the Bet Netofa Valley, random plants of the cultivar Eden released locally with resistance to races 0 and 1 of Fusarium oxysporum Schlecht. f. sp. melonis Leach & Curr. showed yellowing and wilt symptoms. Stems of sections of wilted plants yielded typical colonies of F. oxysporum. For pathogenicity tests, monoconidial isolates were prepared for inoculation of 8-to 10-day-old seedlings of three differentials suggested by Risser et al (2) by dipping their roots into a conidial suspension (1.5 X 106 conidia per milliliter). Only the Doublon differential remained disease-free. All of the seedlings of the other two differentials (Charentais T and CM 17187) died. (Eden is derived from CM 17187, and although resistance to race 1 also confers resistance to race 0, the reverse is not necessarily true.) On the basis of these findings, the Israeli isolate was designated as F. o. f. sp. melonis race 2 (sensu Risser et al [2]). Race 0 and race 1 have been reported from Israel (1), but this is the first record of race 2 in Israel.

References: (1) D. Netzer and C. Weintall. Phytoparasitica 7:203, 1979. (2) G. Risser et al. Phytopathology 66:1105, 1976.