Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 9, 1998
Publication Date: N/A
Technical Abstract: Over the past 30 years, extensive research has been conducted to develop the "bioherbicide approach" for controlling weedy plants. Despite this success in discovering potential bioherbicides, only four mycoherbicides have been registered for use in North America and only two of these products are currently in the marketplace. While regulatory issues and market demand have hindered the development of some potential bioherbicides, the overall lack of commercial success in using living microbial biocontrol agents stems from difficulties in producing and stabilizing these agents and from the lack of consistent effective weed control in field situations. Low-cost production and formulation methods which yield stable, effective fungal propagules are needed to overcome these constraints. Using liquid culture fermentation, the nutritional environment can be manipulated during culture growth and propagule formation to yield superior mycoherbicides. Our liquid culture studies with the bioherbicidal fungus Colletotrichum truncatum have demonstrated that nutrition impacts not only spore yield but also spore efficacy in controlling the weed hemp sesbania. Nutritional conditions have also been identified which inhibit sporulation and promote the production of high concentrations of microsclerotia of C. truncatum in liquid culture. In addition, formulation can also be used to increase propagule stability and biocontrol efficacy under field conditions.