Septoria Leaf Spot
Septoria lycopersici
A widespread fungal disease of tomatoes and other members of the nightshade family, causing numerous small spots on the leaves.
Symptoms
- Many small, water-soaked spots on lower leaves that enlarge to about 1/8 inch.
- Spots develop gray or tan centers with dark borders.
- Tiny black specks (fruiting bodies of the fungus) may appear in the center of spots.
- Affected leaves turn yellow, wither, and fall off.
Causes
- Fungus survives on infected plant debris or on solanaceous weeds.
- Spores are spread by splashing water and wind.
- Moderate temperatures and high humidity favor disease development.
Prevention
- Remove infected debris and control weeds.
- Improve air circulation between plants.
- Mulch plants to prevent water splashing from the soil.
- Avoid overhead watering.
Treatments
- Remove and destroy infected leaves.
- Apply fungicides containing chlorothalonil or copper.
- Begin treatment as soon as symptoms appear and repeat as per label instructions.