VIEW ARTICLE

Disease Control and Pest Management

Evaluation of Cercospora rodmanii as a Biological Control of Waterhyacinths. Kenneth E. Conway, Assistant Research Scientist, Plant Pathology Department, University of Florida, Gainesville 32611; Phytopathology 66:914-917. Accepted for publication 20 February 1976. DOI: 10.1094/Phyto-66-914.

A fungus, Cercospora rodmanii Conway, which was isolated from declining waterhyacinths in Rodman Reservoir in Florida, was evaluated for its biological control potential on waterhyacinths during two growing seasons (February-November). Results of greenhouse and field studies indicated that the fungus was responsible for the waterhyacinth decline. Infection was initiated on waterhyacinths in Lake Alice on the University of Florida campus during September and October, 1974. A combination of conidia and mycelia was applied to the plants. When the inoculum level was increased by a second similar spray application the disease spread rapidly. Browning of the waterhyacinths in the test pool was augmented in the later stages of the test by below-freezing temperatures. Cercospora rodmanii can be a virulent pathogen on waterhyacinth and its effect on field populations of waterhyacinth will be evaluated further to quantify damage to the plant.