SPATIAL DISTRIBUTION OF FUSARIUM CROWN AND ROOT-ROT OF TOMATO AND PATHOGEN DISSEMINATION IN FIELD SOIL
Y REKAH1, D SHTIENBERG
1Department of Plant Pathology and Microbiology, The Hebrew University of Jerusalem, Faculty of Agricultural, Food and Environmental Quality Sciences, Rehovot 76100, Israel;
Background and objectives Tomato crown and root-rot, caused by Fusarium oxysporum f. ;sp. radicis-lycopersici is a potentially destructive disease. It is generally accepted that most soil-borne pathogens are monocyclic in nature, whereas foliar pathogens are polycyclic, although some exceptions exist. Such characterization of pathogens has important consequences for disease management. The purpose of this study was to determine whether F. ;o. f. ;sp. radicis-lycopersici is a polycyclic pathogen, namely, if it has the ability to complete several disease cycles per growing season.
Materials and methods
Semivariogram function was calculated separately for each experimental plot for each of the disease assessments. The spread of the pathogen from diseased to neighbouring plants was also studied in fumigated plots using tagged inoculum as nit mutants of the pathogen . On planting day, bags with inoculum were placed near the plant root and pathogen's spread was determined by plating roots of diseased adjacent plants on chlorate amended selective medium.
Results and conclusions
These findings suggest a polycylic nature of F. ;o. f. ;sp. radicis-lycopersici, which differs from the monocyclic nature of many soil-borne pathogens.