Common crops affected
What is it?
Early blight is caused by Alternaria fungi. It survives in soil and crop debris and spreads in warm, humid weather via splashing water and wind. It typically appears first on older, lower leaves and progresses upward, and it is favored by plant stress and crowded, wet conditions.
How to identify it
- Dark brown to black spots with concentric rings (a target-like or bullseye look)
- Yellowing around the spots, starting on the lowest, oldest leaves
- Progressive defoliation moving up the plant
- Dark, sunken lesions on stems and fruit or tubers in severe cases
Damage and how it spreads
By defoliating the plant from the bottom up, early blight reduces photosynthesis, weakens plants, and exposes fruit to sunscald and tubers to infection — cutting both yield and quality. It returns from soil and debris each season, so sanitation and protective treatment are key to keeping it in check.
How to control it
- Remove and destroy infected lower leaves and end-of-season debris.
- Mulch to reduce soil splash, and rotate away from tomatoes and potatoes.
- Stake and space plants for airflow; avoid overhead watering.
- Apply a protective natural fungicide at first sign and through warm, humid weather.
Recommended Vegalab solution: Spore Control
Vegalab Spore Control (Thymol) protects against early blight by forming a film on the plant cuticle and inhibiting spore germination and mycelium growth. Apply as a foliar spray at first sign of disease, diluted 1:1,000 (1 mL/L), with thorough lower-canopy coverage, and maintain protection through warm, humid spells. Sanitation and mulch make the program more effective.
| Role | Product | Use |
|---|---|---|
| Primary control | Spore Control | Broad-spectrum protective fungicide |
| Companion / broader pressure | Armour Boost | Silica for tissue resilience |
Preventing it next season
Rotate crops, mulch, space and stake plants, remove debris, and start protective sprays before disease pressure builds in warm, humid weather. Keep plants unstressed and vigorous with balanced nutrition and Armour Boost.
Claims and product availability vary by jurisdiction. Always read and follow the product label.