Production and Management
The term plant disease, as used in this publication, refers to a plant problem caused by a pathogen, such as a fungus, bacterium, virus or nematode. Other types of plant problems include disorders, caused by cultural or environmental factors, and pest damage, caused by insects or other animals that feed on or otherwise damage plants. This publication only deals with pathogen control and does not address disorders and pest damage.
"W141-2010 Commercial Vegetable Disease Control Guide," The University of Tennessee Agricultural Extension Service, , http://trace.tennessee.edu/utk_agexcomhort/30