EPIDEMIOLOGY AND MANAGEMENT OF BOTRYTIS LEAF-BLIGHT OF ONION AND GRAY MOLD OF STRAWBERRY - A COMPARATIVE-ANALYSIS

Epidemics of onion leaf blight, caused by Botrytis squamosa, and strawberry gray mold, caused by B. cinerea, are considered in terms of host development, inoculum, infection and colonization of the host, symptom development and disease progress. Implications and applications of the epidemiologic information in disease management are discussed with emphasis on methods that reduce fungicide-dependency of management programs. Methods to suppress inoculum at the source are evaluated in the context of relationships of initial inoculum with disease progress and effectiveness for disease management. The methods for leaf blight include removal of onion cull piles, destruction of volunteer onions, tillage practices, periodic flooding of the soil, crop rotation and host management. The methods considered for the fruit rot phase of gray mold are removal or destruction of foliar residues, and application of fungicides to green and dead foliage in the autumn or early spring. Techniques are considered also for protecting the host and suppressing disease increase. These are, for leaf blight, weatherbased disease forecasters to time fungicide sprays and, for gray mold, applications of biocontrol agents and nutrients. Contrasts and similarities of leaf blight and gray mold are identified. © 1990 Taylor & Francis Group, LLC.