Common crops affected
What is it?
Downy mildew is caused by water moulds (oomycetes), not true fungi. It thrives in cool, wet, humid conditions and spreads explosively when leaves stay wet. The pathogen infects leaf tissue and produces spores on the underside, which then spread on wind and splashing water.
How to identify it
- Pale yellow to brown angular patches on the upper leaf surface, often bounded by veins
- Fuzzy gray, purple, or white growth on the underside beneath those patches
- Rapid spread in cool, wet, humid weather
- Leaves brown, curl, and die in severe cases, reducing yield
Damage and how it spreads
Because it spreads so fast in wet weather, downy mildew can cause severe defoliation and crop loss quickly. The loss of leaf area cuts photosynthesis and yield, and in crops like grapes and cucurbits it is one of the most economically important diseases. Early, preventive action is essential.
How to control it
- Improve airflow and avoid prolonged leaf wetness — water at the base, early in the day.
- Remove and destroy infected leaves promptly.
- Rotate crops and choose resistant varieties where available.
- Apply a protective natural fungicide at first sign and ahead of wet weather on susceptible crops.
Recommended Vegalab solution: Spore Control
Vegalab Spore Control is an all-natural broad-spectrum fungicide powered by Thymol (Thymus vulgaris oil). It forms a protective film over the plant cuticle and inhibits spore germination and mycelium proliferation, inducing a K+ ion imbalance that causes fungal cell lysis. It targets downy and powdery mildew, anthracnose, gray mold, damping-off, phytophthora, and wilt. Apply as a foliar spray at first sign of disease, diluted 1:1,000 (1 mL/L). Mildew Control (Geraniol) is a strong companion where mildews dominate.
| 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 |
Preventing it next season
Manage moisture aggressively, space and prune for airflow, rotate crops, and begin preventive sprays before wet spells on high-risk crops. Build plant resilience with Armour Boost.
Claims and product availability vary by jurisdiction. Always read and follow the product label.