Formulation of mycoherbicidal strains of Fusarium oxysporum

Biomass abundant in chlamydospores obtained by liquid fermentation of mycoherbicidal strains of Fusarium oxysporum was incorporated into alginate prills with various food substrates and granular formulations such as corn flour : starch, wheat flour : kaolin, rice : wheat flour, and rice : wheat gluten formulations. These fungal strains cause vascular wilts in coca (Erythroxylum coca var. coca) and in poppy (Papavar somniferum). Fungal strain, formulation method, and interaction of these two parameters significantly affected the shelf life of the formulations at room temperature as well as the ability to form secondary propagules on 1% water agar. In bioassays, there were no significant differences among F. oxysporum strain EN4-S formulations in their ability to colonize root tissue or the rhizosphere of E. coca seedlings. The study indicates that most of the formulations meet at least three of the four criteria important for biological control agents to be effective: low losses in viability during the formulation process, satisfactory shelf life at room temperature, abundant secondary chlamydospore formation, and rhizosphere colonization.