Early blight (Alternaria) on tomato
DiseaseDark spots with concentric rings often start on older leaves and move up the plant.
Often on
Tomatoes and potatoes; common where leaves stay humid.
Symptom tags
Signs in the garden
- Target-like lesions; yellow halos sometimes.
- Lower canopy defoliates first; fruit is rarely the first symptom.
What often helps (general)
- Mulch to reduce soil splash onto lower leaves.
- Stake/prune for airflow; water at the base in the morning.
- Rotate nightshades on a multi-year cycle where space allows.
When to escalate
If lesions climb to growing tips quickly or stems show sunken cankers, get ID help — late blight and other issues differ in urgency.