Association of Sugarcane Rust Severity with Soil Factors in Florida. D. L. Anderson, Associate Professor of Agronomy, University of Florida, Everglades Research and Education Center, Belle Glade 33430. R. N. Raid, M. S. Irey, and L. J. Henderson. Assistant Professor of Plant Pathology, University of Florida, Everglades Research and Education Center, Belle Glade 33430; Plant Pathologist, and Soil Scientist, Research Department, U.S. Sugar Corporation, Clewiston 33440. Plant Dis. 74:683-686. Accepted for publication 14 February 1990. Copyright 1990 The American Phytopathological Society. DOI: 10.1094/PD-74-0683.

Sugarcane production in Florida has been affected by sugarcane rust, caused by Puccinia melanocephala, since the first recorded outbreak of the disease in 1979. During 1988 and 1989, seven first-year production fields exhibiting high variability in rust severity were selected for study. Each field site was spatially sampled for soil variability and assessed for rust infection levels. Although rust severities are negatively correlated with soil pH at each and across all locations, rust severity is site- and cultivar-specific. Soil pH is an important criteria, but it is not the sole determinant affecting rust severity in sugarcane. High levels of soil phosphorus were also associated with high rust severity at all locations. At two locations, high levels of soil magnesium and potassium were associated with lower rust severity. These associations, although not conclusive of a causal relationship, provide a basis for identifying soil conditions promoting high rust intensity as well as for directing sugarcane rust research in the future.