Tomato Blight? Don't Panic—Identify, Treat, and Prevent

Last year's late blight devastated tomato crops, but most foliar diseases are far more manageable. Don't despair at the first spot—act smart.

Start Clean

• Ferment saved seeds to kill pathogens.
• Buy healthy plants—check neighbors in the flat for spots/yellowing.

Cultural Prevention

• Water at base (soaker hoses)—wet foliage breeds fungi.
• Space widely; prune for airflow.
• Mulch to prevent soil-splash onto leaves.
• Remove low branches touching soil.

At First Sign of Trouble

• Prune diseased leaves/branches; disinfect tools between plants.
• Trash—don't compost—infected material.
• Switch to bottom watering; improve airflow.
• Most diseases don't require immediate plant removal (unlike late blight).

Treatment Options

• Chlorothalonil (Daconil/Ortho Garden Disease Control): Effective against fungal blights.
• Copper sprays: Work on fungi/bacteria; "organic" but potentially more toxic than synthetics.
• Organic alternatives: Neem oil, milk sprays, Messenger—may help early, less effective on advanced infections.
• Spray preventatively or at first symptom for best control.

Diagnosis Tips

Early-season spots that persist >1 week = not late blight. Common culprits: Septoria Leaf Spot, Early Blight. Bacterial Speck, Grey Mold also possible. Curling leaves = spider mites, herbicide drift, or uneven watering. Defoliation = hornworms (look for dark frass), rabbits/groundhogs (provide water source).

End-of-Season Cleanup

Don't compost or till in diseased plants—spores overwinter. Remove and trash or burn (per local rules). Rotate tomatoes: same spot ≤1 year in 3. Single rows > patches; cage/stake for airflow.

Bottom Line

Tomatoes are tough. Ugly plants can still yield well. Monitor, act early, and don't give up.