Early Blight
Alternaria linariae (A. solani) · fungus
- Issue type
- disease
- Seedborne
- Yes, travels on seed
- Resistance code
- EB, AB
- Affects
- Tomato
Symptoms
Brown lesions with concentric target-board rings on lower leaves first, yellowing and defoliating upward as fruit load peaks; stem lesions (collar rot) on seedlings and dark sunken shoulders on fruit. The most common tomato foliar disease in most of the country.
Management
Defense in depth: mulch to stop soil splash, stake and prune for airflow, rotate 2-3 years, remove infected lower leaves early, and use tolerant varieties, several modern hybrids (e.g. Mountain Magic, Iron Lady, Defiant PhR) carry real early blight tolerance, a meaningful shift after decades where none existed. Protectant fungicides on a schedule carry commercial fields.
Varieties with documented resistance
| Variety | Level | Code | Days | Breeding |
|---|---|---|---|---|
| Juliet | tolerant | - | 60-62 | F1 hybrid |
| Mountain Magic | tolerant | - | 66-70 | F1 hybrid |
| Defiant PhR | intermediate | - | 65-70 | F1 hybrid |
| Iron Lady | tolerant | - | 75-80 | F1 hybrid |
| Jasper | tolerant | - | 60-65 | F1 hybrid |
| Galahad | tolerant | - | 69-75 | F1 hybrid |
Sources & References
Evidence: 1 source, all independent references.
- Vegetable MD Online · Cornell University, Plant Pathology, University or Government