FORMULATION OF MYCOHERBICIDAL STRAINS OF FUSARIUM-OXYSPORUM

Biomass abundant in chlamydospores obtained by liquid fermentation of mycoherbicidal strains of Fusarium oxysporum was incorporated into alg inate prills with various food substrates and granular formulations su ch as corn flour:starch, wheat flour:kaolin, rice:wheat flour, and ric e:wheat gluten formulations. These fungal strains cause vascular wilts in coca (Erythroxylum coca var, coca) and in poppy (Papavar somniferu m). Fungal strain, formulation method, and interaction of these two pa rameters significantly affected the shelf life of the formulations at room temperature as well as the ability to form secondary propagules o n 1% water agar. In bioassays, there were no significant differences a mong ii oxysporum strain EN4-S formulations in their ability to coloni ze root tissue or the rhizosphere of E. coca seedlings. The study indi cates that most of the formulations meet at least three of the four cr iteria important for biological control agents to be effective: low lo sses in viability during the formulation process, satisfactory shelf l ife at room temperature, abundant secondary chlamydospore formation, a nd rhizosphere colonization.