Common crops affected
- Tomato
- Potato
- Cucurbits
- Brassicas
What is it?
This is a complex of common foliar fungi that infect leaves (and sometimes stems and fruit), producing spots that enlarge and merge into blighted, dying tissue. They survive in debris and spread by splash and wind in wet conditions.
How to identify it
- Round to angular leaf spots, often with concentric rings (Alternaria) or pale centres with dark borders (Cercospora).
- Spots enlarging and coalescing into blighted, dying areas; lower/older leaves first.
- Premature yellowing and defoliation from the bottom of the canopy upward.
- Reduced canopy and exposed/sun-damaged fruit in severe cases.
Life cycle & spread
Survives in crop debris and seed; spores spread by rain splash and wind to new foliage; cycles rapidly in warm, wet, humid weather with repeated leaf wetness.
Conditions that favour it
Warm temperatures, frequent leaf wetness/humidity, dense canopies, and carry-over inoculum in debris.
Damage and how it spreads
Progressive defoliation reduces photosynthesis, yield and fruit quality, and exposes fruit to sunscald.
Monitoring & scouting
Scout lower/older leaves first in warm wet spells; act preventively as conditions favour disease rather than waiting for heavy blighting.
How to control it
- Improve airflow, manage leaf wetness and canopy density, remove debris, and apply protectant programs preventively and at first symptoms.
Recommended Vegalab solution: Spore Control
Spore Control — natural broad-spectrum fungicide (thymol) applied preventively under favourable conditions and at first symptoms, with thorough canopy coverage; combine with airflow and sanitation.
| Role | Product | Use |
|---|---|---|
| Primary control | Spore Control |
Preventing it next season
Airflow/canopy management, leaf-wetness reduction, debris sanitation, crop rotation and preventive sprays in warm wet periods.
Claims and product availability vary by jurisdiction. Always read and follow the product label.