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Disease Note.

First Report of Corky Dry Rot of Cantaloupe Caused by Fusarium semitectum in Florida. R. J. McGovern, University of Florida, Southwest Florida Research and Education Center, Immokalee 33934. Plant Dis. 78:926,. Accepted for publication 16 June 1994. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0926B.

Corky dry rot of cantaloupe (Cucumis melo L), caused by Fusarium semitectum Berk. & Ravenel, has been reported in eastern, central, and western states in the United States and from Texas (I) and North Carolina (2). The disease was detected in three fields in southwest Florida, which accounted for over 75% of the area’s cantaloupe production in spring 1991 and fall 1993. Disease incidence was approximately 60% in the cantaloupe cultivar Nova and 80% in Primo in 1991, and 30% in Hymark in 1993. Dark, round (5-8 cm), slightly sunken, spongy areas were observed on the rinds of fruit nearing maturity. Dark brown, corky areas were seen beneath the rind, which cracked as lesions expanded. Prior to cracking, lesions seldom extended more than a few centimeters into the fruit. A white mycelium, which became covered with orange spore masses, was common in cracked areas. F. semitectum was consistently isolated (acidified PDA) from surfaced-disinfested tissue pieces taken from lesion margins beneath the rind. The rinds of two surface-disinfested cantaloupe fruit were inoculated by placing agar plugs from a 1-wk-old culture of F. semitectum in each of five wounds. The inoculated fruit and two wounded, noninoculated controls were incubated in a moist chamber at day/night temperatures of 28 C/20 C. Characteristic corky, dry rot lesions developed beneath the rind after 7 days, and F. semitectum was reisolated from the inoculated fruit but not from noninoculated controls. This is the first report of corky dry rot of cantaloupe in Florida.

Reference: (I) Carter. Plant Dis. Rep. 63:1080, 1979. (2) Raymond et al. Mycologia 51:492, 1959.