Susceptibility of Summer Squash to the Watermelon Wilt Pathogen (Fusarium oxysporum f. sp. niveum). R. D. Martyn, Assistant Professor, Plant Sciences Department, Texas A&M University, College Station 77843. R. J. McLaughlin, Research Associate, Plant Sciences Department, Texas A&M University, College Station 77843. Plant Dis. 67:263-266. Accepted for publication 3 August 1982. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-263.

Thirty-four cultivars encompassing six species of Cucurbita were tested for susceptibility to Fusarium oxysporum f. sp. niveum. All were resistant except 10 cultivars or hybrid accessions of Cucurbita pepo var. melopepo that include zucchini and yellow summer squashes. Percentage wilt in the susceptible cultivars ranged from 37 to 100%. Golden Eagle, Hyrific, Straightneck, and Early Prolific Straightneck were the most susceptible. Yellow Crookneck was resistant to F. oxysporum f. sp. niveum as were bush scallop, cushaw, and pumpkin. Resistance of certain cultivars to F. oxysporum f. sp. niveum was attributed to a reduced level of colonization in the vascular tissue rather than lack of penetration by the fungus.

Keyword(s): Citrullus lanatus.