VIEW ARTICLE

Ecology and Epidemiology

Epidemiological and Mycofloral Relationships in Cotton Seedling Disease in Mississippi. K. W. Roy, Department of Plant Pathology, Mississippi State University, Mississippi State 39762; F. M. Bourland, Weed Science and Department of Agronomy, Mississippi State University, Mississippi State 39762. Phytopathology 72:868-872. Accepted for publication 11 December 1981. Copyright 1982 The American Phytopathological Society. DOI: 10.1094/Phyto-72-868.

Cotton seedlings and soil adjacent to seedlings were collected from various locations in Mississippi. Seedlings were evaluated for incidence of fungi on root and hypocotyl tissues. Selected seedling, fungal, and soil variables were analyzed for possible correlations. Of more than 50 different fungi isolated from seedlings, Fusarium oxysporum was the most frequent, followed by Rhizoctonia solani, Thielaviopsis basicola, Fusarium equiseti, and F. solani. Most fungi were isolated more frequently from young than old root and hypocotyl tissues. In pathogenicity tests, isolates of F. oxysporum, R. solani, and T. basicola were pathogenic to seedlings. Incidence of F. oxysporum on seedlings was positively correlated with root disease index, hypocotyl disease index, and total soil N/ha and negatively correlated with soil pH. Incidence of T. basicola on seedlings was positively correlated with soil pH, root disease index, and hypocotyl disease index and negatively correlated with seedling population. Incidence of R. solani on seedlings was positively correlated with hypocotyl disease index. Root disease index was positively correlated with hypocotyl disease index and negatively correlated with seedling population.