VIEW ARTICLE

Ecology and Epidemiology

Application of Two Epidemiological Models for the Identification of Slow Stem Rusting in Wheat. D. R. MacKenzie, Former Rockefeller Foundation Post-Doctoral Fellow, The International Center for Maize and Wheat Improvement (CIMMYT), Londres 40, Mexico 6, D. F., Mexico, Present address: Department of Plant Pathology, The Pennsylvania State University, University Park 16802; Phytopathology 66:55-59. Accepted for publication 16 July 1975. DOI: 10.1094/Phyto-66-55.

Two stem rust (caused by Puccinia graminis f. sp. tritici)-susceptible spring wheat cultivars (Pitic 62 and Penjamo 62) were compared to the slow rusting cultivar Bonza 55 for those gross epidemiological attributes (i.e. reduced spread, rate of increase) which might characterize slow rusting. Analyses of physically isolated stem rust epidemics indicated that reduced spread and lessened rates of increase on Bonza 55 relative to the susceptible varieties, characterized slow rusting. Application of these relationships to the identification of slow rusting is proposed. This method would combine the slow rusting components of rate of disease increase and spread into a single slow rusting index.