title: A Physically Based Theoretical Model of Spore Deposition for Predicting Spread of Plant Diseases.
abstract: A physically based theory for predicting spore deposition downwind from an area source of inoculum is presented. The modeling framework is based on theories of turbulence dispersion in the atmospheric boundary layer and applies only to spores that escape from plant canopies. A "disease resistance" coefficient is introduced to convert the theoretical spore deposition model into a simple tool for predicting disease spread at the field scale. Results from the model agree well with published measurements of Uromyces phaseoli spore deposition and measurements of wheat leaf rust disease severity. The theoretical model has the advantage over empirical models in that it can be used to assess the influence of source distribution and geometry, spore characteristics, and meteorological conditions on spore deposition and disease spread. The modeling framework is refined to predict the detailed two-dimensional spatial pattern of disease spread from an infection focus. Accounting for the time variations of wind speed and direction in the refined modeling procedure improves predictions, especially near the inoculum source, and enables application of the theoretical modeling framework to field experiment design.
authors.affiliation: First author: Department of Plant Pathology and Environmental Microbiology and Department of Meteorology, and second author: Department of Meteorology, The Pennsylvania State University, University Park 61802.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Isard
authors.affiliation: First author: Department of Plant Pathology and Environmental Microbiology and Department of Meteorology, and second author: Department of Meteorology, The Pennsylvania State University, University Park 61802.
authors.forename: Marcelo
authors.initials: M
authors.lastname: Chamecki
mesh_terms: D001487:Basidiomycota / Q000502:physiology*; D008954:Models, Biological; D010935:Plant Diseases / Q000382:microbiology*; D013172:Spores, Fungal / Q000502:physiology*; D014908:Triticum / Q000382:microbiology*
keywords: canopy escape; power law