Peronosporaceae spp.

Downy mildew is a water-loving fungal-like disease that strikes fear in the hearts of home gardeners, especially during cool, damp periods. It thrives under high humidity and spreads rapidly through spores that land on the undersides of leaves, where they form a fuzzy white, cream, grey or even purplish growth. Affected leaves may yellow and collapse, weakening the plant and slashing yields. Crops like cucumbers, pumpkins, squashes, lettuce, and even basil are particularly vulnerable, with outbreaks often wiping out entire beds if not caught early.

This disease is costly in every sense. Once symptoms appear, control becomes difficult and treatments must be repeated, raising both input costs and time spent spraying. For the home gardener, the best line of defense is prevention. A proactive approach using organic methods reduces losses and builds long-term resilience into your garden.

To keep downy mildew at bay, water early in the morning and only at the soil level. This gives leaves time to dry before evening, when moisture lingers and promotes infection. Preventative sprays, rotated through compatible products, offer solid protection through the season.

• Biologicals

  • Double Nickel 55 
    A foliar-applied biological fungicide with Bacillus amyloliquefaciens. Prevents and suppresses downy mildew by colonising the leaf surface. Do not mix with copper sprays.

    Péllos
    A microbial fungicide with Ampelomyces quisqualis, which parasitises fungi such as downy mildew and powdery mildew. Provides residual protection for up to 21 days and is suited to regular preventative programs.

• Organics

  • Copper Soap
    Combines soluble copper with fatty acids for preventative control of downy mildew, among others. Apply as a foliar spray but avoid using in combination with microbial-based products like Double Nickel and Péllos.

Note: Rotate between products like Copper Soap and Double Nickel 55 and Péllos to reduce resistance pressure. Do not tank mix biologicals with copper-based sprays.