Forum is one of the only systemic fungicides with antisporulant activity that fights sporangia before the fungalspores have a chance to form and produce destructive zoospores that infect tubers and leaves.The spore-stopping effect of Forum can control the further spread of downy mildew in already infected fields.
Forum's active ingredient is dimethomorph. This class of fungicides is very susceptible to build up of resistant downy mildew. It should only be applied in rotation with other mode of action (MOA) fungicides and never twice in a row without another fungicide. It cannot be applied to hops aerially or through drip irrigation. Through spray coverage is essential, so proper nozzle selection (like hollow cone) and addition of a surfactant/ spreader/sticker is recommended for best control results.