Disease Note.

First Report of Fusarium oxysporum f. sp. lycopersici Race 3 on Tomato in Northwest Florida and Georgia. D. O. Chellemi, North Florida Research and Education Center, Route 3, Box 4370, Quincy 32351. H. A. Dankers, and B. Crosier. North Florida Research and Education Center, Route 3, Box 4370, Quincy 32351, and Glades Crop Care, Inc., 949 Turner Quay, Jupiter, FL 33458. Plant Dis. 76:861. Accepted for publication 10 March 1992. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0861D.

During the 1991 production season. symptoms of Fusarium wilt were observed on tomato (Lycopersicon esculentum Mill.) cultivars with resistance to races 1 and 2 in two commercial production fields in northwest Florida and one in southwest Georgia. Discolored vascular tissue plated on potato-dextrose agar consistently yielded Fusarium oxysporum Schlechtend.:Fr. f. sp. lycopersici (Sacc.) W.C. Synder & H.N. Hans. Presence of race 3 was determined with the cullivars Bonny Best (no tolerance or resistance genes), Manapal (1 gene for resistance to race I). Walter (1 and 12 genes for resistance to races I and 2), and 3WR (1, 12, and 13 genes for resistance 10 races 1, 2, and 3). Cultivars were inoculated by immersing the roots of 3-wk-old seedlings into a 200-ml suspension of 1.4-2.6 X 10⁵ micro-conidia per milliliter for 30 sec. Seedlings were then transplanted into 6.5-cm pots containing sterile potting mix and placed in the greenhouse. Inoculations were performed with single spore isolates from three different fields. At 3 wk after inoculation, only plants with resistance to race 3 and control plants immersed in sterile water had remained healthy. The pathogen was reisolated from all planls with symptoms of Fusarium wilt. This is the first report of race 3 of F. o. lycopersici in northwest Florida and Georgia. Approximalely 2,000 ha of fresh market tomatoes are grown in northwest Florida and southwest Georgia, and at the present time. commercially acceptable tomato cultivars with resistance to race 3 are not available.