Co-Authors: Joffe, A.Z., Department of Botany, Hebrew University, Jerusalem, Israel Palti, J., Department of Plant Protection, Extension Services, Ministry of Agriculture, Tel-Aviv, Israel
Abstract: Fusarium javanicumKds. has been isolated from wilted vegetable marrows and melons and from the soil of a citrus grove in Israel. The morphology of the species is described, and measurements and drawings of macroconidia are presented. In vitro tests showed that F. javanicum failed to develop at either 12 or 40° C, and developed better at 24° C than 18 or 30° C. Mycelial growth on potato dextrose agar was always better at pH 7 than at pH 4.2. Darkness favored such growth to a marked extent only at 18° C and pH 4.2. In glasshouse inoculation tests one isolate of F. javanicum from vegetable marrow proved clearly pathogenic to cucumber, melon, watermelon and marrow. Measurements of macroconidia have been made, for comparative purposes, on isolates of F. javanicum var. ensiforme and of F. solani f. cucurbitae furnished from abroad, and on isolates of F. solani from cucurbits in Israel. Comparing the data for 3-septate macroconidia with those given in literature for F. solani and for F. javanicum and its var. radicicola and var. ensiforme, it is concluded that two groups can be distinguished: One group comprises, with one exception, all isolates of F. javanicum and its varieties as well as F. solani f. cucurbitae, and is characterized by slender macroconidia. The other group is represented by F. solani with its typically sausage shaped conidia. It is concluded that F. javanicum should be maintained as a species distinct from F. solani. It is further suggested that what has been called F. solani f. cucurbitae may have closer affinity to F. javanicum than to F. solani. © 1970 Dr. W. Junk N.V.