Fermentation strategies for improving the fitness of a bioherbicide

• Published in: Weed technology Vol. 10; no. 3; pp. 645 - 650
• Main Authors: Jackson, M.A, Schisler, D.A, Slininger, P.J, Boyette, C.D, Silman, R.W, Bothast, R.J
• Format: Journal Article
• Language: English
• Published: Weed Science Society of America 01-07-1996
• Subjects: AGENT PATHOGENE; AMENDEMENT DU SOL; AUXILIAIRE DE LUTTE BIOLOGIQUE; BIOLOGICAL CONTROL; BIOLOGICAL CONTROL ORGANISMS; Carbon; Colletotrichum; COLLETOTRICHUM TRUNCATUM; Conidia; CONTROL BIOLOGICO; CULTIVO IN VITRO; CULTURE IN VITRO; CULTURE MEDIA; DESHERBAGE; EFFICACY; ENFERMEDADES FUNGOSAS; ENMIENDAS DEL SUELO; ESCARDA; ESPORULACION; FERMENTACION; FERMENTATION; FUNGAL DISEASES; FUNGAL MORPHOLOGY; Fungal spores; Fungi; Hemp; HERBICIDAS; HERBICIDE; HERBICIDES; IN VITRO CULTURE; Liquids; LUTTE BIOLOGIQUE; MALADIE FONGIQUE; MEDIO DE CULTIVO; MICROBIAL PESTICIDES; MILIEU DE CULTURE; MORFOLOGIA FUNGICA; MORPHOLOGIE DE CHAMPIGNON; MYCOHERBICIDES; NEW PRODUCTS; ORGANISMOS PARA CONTROL BIOLOGICO; ORGANISMOS PATOGENOS; PATHOGENS; PESTICIDE MICROBIEN; PLAGUICIDAS MICROBIANOS; PRODUCTOS NUEVOS; PRODUIT NOUVEAU; SCLEROTIA; SESBANIA; SESBANIA EXALTATA; SOIL AMENDMENTS; Spores; SPORULATION; Symposium: Biological Weed Control Symposium; WEED CONTROL
• ISSN: 0890-037X; 1550-2740
• DOI: 10.1017/s0890037x00040574

The commercial development of microbial bioherbicides requires the availability of low-cost production methods. The use of liquid culture fermentation is generally considered necessary to achieve this goal. Our strategy for optimizing liquid culture media is based on using defined nutritional conditions. Specific changes are made in the nutritional environment of the medium and the effect of these changes is assessed in terms of propagule yield, efficacy, and stability of the bioherbicidal agent. Liquid culture studies with the fungus Colletotrichum truncatum have demonstrated that nutrition impacts not only spore yield but also spore efficacy in controlling the weed hemp sesbania. Nutritional conditions were identified which suppressed sporulation and promoted the production of high concentrations of C. truncatum microsclerotia in liquid culture. Microsclerotia of C. truncatum (particle size range = 180 μm to 425 μm) showed 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. By understanding how nutrition impacts propagule formation, yield, efficacy, and stability, rational approaches can be taken to develop submerged culture production methods for microbial biocontrol agents. Breakthroughs in these areas should allow numerous promising bioherbicidal agents to become commercial products.