Disease Note

Fusarium Crown and Root Rot of Greenhouse Tomatoes in Texas. L. W. Barnes, Texas Plant Disease Diagnostic Laboratory, College Station 77843. R. D. Martyn, Texas Agricultural Experiment Station, College Station 77843. Plant Dis. 69:1100. Accepted for publication 11 September 1985. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-1100d.

Fusarium crown and root rot (FCRR) of tomato (Lycopersicon esculentum Mill.), caused by Fusarium oxysporum Schlecht. f. sp. radicis-lycopersici Jarvis & Shoemaker (FORL), was confirmed in Texas in 1984 on mature, fruit-bearing plants of cv. Laura in a commercial greenhouse. In one house, approximately 50% (1,000) of the plants died. The fungus was isolated from lower stem tissue on Komada medium and identified as FORL by cross-inoculations with it and races 1 and 2 of F. oxysporum f. sp. lycopersici (FOL-1 and FOL-2) onto five tomato cultivars: Bonny Best, Tropic, Walter, Laura, and an unnamed FCRR-resistant variety (De Ruiter Seeds, Inc.) FOL-1 caused wilt only in Bonny Best, whereas FOL-2 caused wilt in Bonny Best and Tropic. The Laura isolate was pathogenic to each cultivar tested except the FCRR-resistant variety. Symptoms included chlorosis, stem girdling, root and crown lesions, limited vascular discoloration, and wilting. Maximum disease incidence caused by FORL in Bonny Best. Tropic, Walter, Laura, and the FCRR-resistant variety was 47, 80, 93, 55, and 0%, respectively. The occurrence of FCRR in Texas extends the number of states reporting this disease to five: California, Ohio, Florida, New Hampshire, and Texas.