Compatibility of a Cerscospora rodmanii Formulation with Selected Herbicide Spray Additives

摘要

Cercospora rodmanii Conway, a fungal pathogen, offers promise as a biocontrol of the aquatic plant waterhyacinth (Eichhornia crassipes (Mart.) Solms.). A powered formulation of the pathogen has been developed by Abbott Laboratories, Chicago, Ill. To facilitate the spray application of this formulation, a chemical additive was needed that would not be inhibitory to the fungus. Nine additives commonly used in application of herbicides for control of aquatic plants were tested: Agridex, Big Wet, Cide-Kick 'SA-77,' Lo-Drift, Nalco-Trol, Ortho X-77 Spreader, Peg, Sterox NJ, and Surfel. Each additive was tested at the lowest and highest concentrations recommended by its label. Tests were performed in laboratory cultures by comparing the number of colonies of C. rodmanii produced in the presence of each test agent with the number produced in untreated controls. Results of this study affirm that it would be inadvisble to use eight of these additives with the C. rodmanii formulation at the concentrations recommended by their labels. Ortho X-77 Spreader is recommended for use at the lowest concentration listed on its label.