Septoria Leaf Spot on Tomatoes: Late-Season Disease Management Reality

Those brown/black lower leaves with spots progressing upward are classic septoria leaf spot—a "wet summer" disease that's unstoppable once advanced.

Current Situation

No curative treatment exists at this stage. Infected leaves will continue dying. Focus on harvesting remaining fruit.

Prevention for Next Year

• Rotate tomato locations
• Mulch to prevent soil splash
• Water at soil level, not overhead
• Apply preventive chlorothalonil starting in June if wet weather persists
• Remove all crop debris after harvest

Accept this year's loss; implement prevention for next season.