Compatibility and Infectivity of a Cercospora rodmanii Formulation with Enhancing Agents

摘要

A formulation of the fungus Cercospora rodmanii Conway has been produced as a biocontrol of water hyacinth. To ensure the most efficient germination of the formulation, 12 potential enhancing agents were tested for addition during the spray application. The agents were aspartic acid, glucose, glutamic acid, gum xanthan, nutrient agar, Ortho X-77 Spreader, Tween 20, Tween 60, Tween 80, sodium alginate, Super Slupper, and yeast extract. Compatibility of test agents and combinations of test agents with two lots of the formulation was determined in the laboratory. All agents tested, except Ortho X-77 Spreader, were compatible with the first lot of formulation and four agents--Super Slupper, yeast extract, gum xanthan and aspartic acid--resulted in significantly greater colony counts than controls. All agents, including Ortho X-77 Spreader, were compatible with the second lot and one agent, sodium alginate, resulted in significantly greater colony counts than controls. All combinations of test agents were compatible with both lots of the C. rodmanii formulation. The C. rodmanii formulation was sprayed with test agents on water hyacinth pseudolaminae. Damage was monitored each week for 8 weeks by assigning a disease index to each original and new pseudolaminae. No spots having characteristics suggestive of C. rodmanii infection were observed at any time during the study.