Early Blight
- 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 | Basis | Days | Breeding |
|---|---|---|---|---|---|
| Juliet | tolerant | - | Breeder declared | 60-62 | F1 hybrid |
| Mountain Magic | tolerant | - | Independently observed | 66-70 | F1 hybrid |
| Defiant PhR | intermediate | - | Breeder declared | 65-70 | F1 hybrid |
| Iron Lady | tolerant | - | Independently observed | 75-80 | F1 hybrid |
| Jasper | tolerant | - | Breeder declared | 60-65 | F1 hybrid |
| Galahad | tolerant | - | Breeder declared | 69-75 | F1 hybrid |
This is the page where the difference matters most, because it is where a variety gets chosen for its resistance. Breeder declared means the claim comes from whoever breeds or sells the seed, which for most resistance genes is the only evidence that exists. Independently observed means an institution with no stake in the sale grew the plant and reported what happened.
Sources & References
Evidence: 1 source, an independent reference.
- Vegetable MD Online · Cornell University, Plant Pathology, University or Government