Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: July 24, 1996
Publication Date: N/A
Technical Abstract: The availability of economical methods for producing stable, effective microbial bioherbicides is a major constraint to their commercialization. The use of liquid culture fermentation is generally considered a requirement for success. One strategy for optimizing liquid culture production methods is the use of defined nutritional conditions. By using a defined medium, specific changes can be made in the nutritional environment and the impact of these changes assessed in terms of bioherbicidal propagule yield, efficacy, and stability. Our liquid culture studies with the bioherbicidal fungus Colletotrichum truncatum have demonstrated that nutrition impacts not only spore yield but also the biocontrol efficacy of the spore in controlling the weed hemp sesbania. These studies have led to the development of a liquid culture medium which optimizes spore yield and biocontrol efficacy. Nutritional conditions have also been identified which inhibit sporulation and promote the production of high concentrations of microsclerotia of C. truncatum in liquid culture. Microsclerotia of C. truncatum show promise as bioherbicidal propagules due to their stability as a dry preparation and their efficacy in controlling hemp sesbania when used as a soil amendment. Standardized production methods are required for evaluating bioherbicidal agents and nutrition can be used to regulate bioherbicidal yield, efficacy, and stability.