Vol. 9, Issue 6, Part G (2025)

The fungus Alternaria eichhorniae is being developed as a mycoherbicide to control water hyacinth [Eichhornia crassipes (Mart.) Solms]. Inoculum concentrations above 2% were all equally effective in achieving 100% weed control. Initially, spores or fungal propagules (0 days old) were more virulent than older ones (4 months old). Talc-based formulations of A. eichhorniae were evaluated under natural outdoor conditions in pots. These formulations, developed from pure cultures, allowed spores to germinate and infect the weed under environmental conditions. All formulations induced higher levels of disease in water hyacinth plants. Reducing the talc powder in the dust formulation from 50% to 10% did not affect efficacy. The most virulent fungi A. eichhorniae showed a damage intensity of 85.06% with 2.1×10⁷ cfu per gram at 15 days after spraying at a 2% concentration. These results confirm the utility and feasibility of talc-based mycoherbicide formulations that promote the bioherbicide’s activity.