Effect of Rust on Sugarcane Growth and Biomass. J. C. Comstock, Agricultural Research Service, U.S. Department of Agriculture, Sugarcane Field Station, Canal Point, FL 33438. J. M. Shine, Jr., and R. N. Raid. Florida Sugar Cane League, Canal Point 33438; and University of Florida, Everglades Research and Education Center, Belle Glade 33430. Plant Dis. 76:175-177. Accepted for publication 27 August 1991. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source, The American Phytopathological Society, 1992. DOI: 10.1094/PD-76-0175.

The sugarcane rust pathogen, Puccinia melanocephala, caused significant growth and biomass reductions of sugarcane plants in a replicated pot study. Disease severity, estimated as the percent area infected on the top visible dewlap leaf, was 53.5% on the highly susceptible cultivar B 4362, 6.9% on the moderately susceptible cultivar CP 78-1247, and 2.3% on the resistant cultivar CP 70-1133. In contrast, the level of rust on uninoculated control plants was 1.3% for cultivar B 4362. Uninoculated control plants of the two other cultivars were free of rust. Stalk height reductions caused by rust were 32.6% in cultivar B 4362, 20.1% in cultivar CP 78-1247, and 15.1% in cultivar CP 70-1133. Wet weights were reduced by 40.9% in cultivar B 4362 and 12.3% in cultivar CP 78-1247 because of rust. Correspondingly, dry weights also were reduced in these two cultivars. Wet weight loss was not observed on the rust-resistant cultivar CP 70-1133, although its dry weight decreased by 3.1%. The experimental design allowed for detection of small yield losses.