Common crops affected
What is downy mildew?
Despite the name, downy mildews are not true fungi — they are oomycetes (water moulds), more closely related to algae. They infect through leaf pores and grow inside the plant, then push spore-bearing structures out through the leaf underside. Because they live inside the tissue and depend on moisture, their management differs from powdery mildew.
How to identify downy mildew
- Yellow or pale-green "oil spots" on the upper leaf surface, often bounded by veins so they look angular
- Grey, purple or white fuzzy growth on the underside — the "downy" layer, most visible in humid mornings
- Rapid browning and leaf death as spots merge; on grapes, shoots and clusters can be lost
Conditions that spread it
Downy mildew needs moisture: extended leaf wetness from rain, dew, fog or overhead irrigation, combined with mild temperatures, triggers rapid infection and sporulation. Dense, poorly ventilated canopies accelerate spread. Because it advances so quickly, preventive timing ahead of wet periods is far more effective than catching up after symptoms explode.
Controlling downy mildew naturally
Effective programs are preventive and coverage-driven: protect the canopy before rain, maintain airflow, and rotate modes of action. A rainfast, adherent, nature-derived fungicide suits this because it stays on the canopy through wet weather rather than washing off.
Recommended Vegalab solution: Mildew Control
Vegalab Mildew Control (geraniol-based) and Spore Control are built on the nano-encapsulation platform: the capsule adheres to the canopy and resists wash-off, releasing its active on contact for rainfast protection with zero pre-harvest and zero re-entry interval. Their physical mode of action makes them practical rotation partners. OMRI-listed options are available. Results vary by crop, region and disease pressure; claims and availability vary by jurisdiction — always read and follow the applicable product label.
| Role | Product | Use |
|---|---|---|
| Primary control | Spore Control | Broad-spectrum protective fungicide |
| Companion / broader pressure | Mildew Control | Geraniol fungicide for mildews |
| Plant support | Armour Boost | Silica for tissue resilience |
Claims and product availability vary by jurisdiction. Always read and follow the product label.