Potential Range of Phymatotrichum omnivorum as Determined by Edaphic Factors. R. G. Percy, Research Associate, Plant Sciences Department, Texas Agricultural Experiment Station, Texas A&M University, College Station 77843. Plant Dis. 67:981-983. Accepted for publication 21 February 1983. Copyright 1983 American Phytopathological Society. DOI: 10.1094/PD-67-981.

Based on a search of the literature, a potential range distribution for P. omnivorum has been developed using edaphic factors. Soil base exchange capacity, pH, sodium content, calcium content, and clay fraction were determined to be factors delimiting occurrence and survival of the fungus. A nonedaphic factor considered was mean annual air temperature. Soil types possessing the necessary characteristics were identified using the FAO-UNESCO soil-classification system. A map of the potential distribution of P. omnivorum in North America was produced and a comparison made with the known distribution of Phymatotrichum root rot disease. The two distributions were coterminous. Distribution of P. omnivorum-conducive soils in South America, Africa, and India was also examined.