Gray Leaf Spot
- Issue type
- disease
- Seedborne
- No
- Resistance code
- St
- Affects
- Tomato
Symptoms
Small dark spots that turn gray-brown, crack, and shot-hole, on foliage only, fruit stays clean while the canopy thins. Mostly a warm-region disease.
Management
The Sm resistance gene (code St) is bred into most southern-adapted hybrids, which is why the disease now shows mainly in heirloom plantings across the South.
Varieties with documented resistance
| Variety | Level | Code | Basis | Days | Breeding |
|---|---|---|---|---|---|
| Big Beef | resistant | St | Breeder declared | 70-73 | F1 hybrid |
| Florida 91 | resistant | St | Independently observed | 70-74 | F1 hybrid |
| Solar Fire | resistant | St | Independently observed | 70-75 | F1 hybrid |
| Manalucie | resistant | St | Independently observed | 80-85 | open-pollinated |
| Floradade | resistant | St | Independently observed | 75-80 | open-pollinated |
| Marion | resistant | St | Breeder declared | 75-80 | open-pollinated |
| Tropic | resistant | St | Breeder declared | 80-85 | open-pollinated |
| Rebelski | resistant | St | Breeder declared | 75-80 | F1 hybrid |
| Red Deuce | resistant | St | Breeder declared | 70-75 | F1 hybrid |
| Skyway 687 | resistant | St | Independently observed | 72-78 | F1 hybrid |
| Florida 47 | resistant | St | Independently observed | 72-78 | F1 hybrid |
| Heatmaster | resistant | St | Breeder declared | 70-75 | F1 hybrid |
| Phoenix | resistant | St | Independently observed | 72-78 | F1 hybrid |
| Bigdena | resistant | St | Breeder declared | 75-80 | 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.
- Tomato Production and Cultivar Guides · University of Florida IFAS Extension, University or Government