Overview
This lecture explains how to identify, manage, and treat fungal diseases on tomato plants to maintain continuous harvests using various fungicidal sprays and proper gardening routines.
Identifying Fungal Issues on Tomato Plants
- Look for brown spots with yellow halos on leaves; this indicates active fungal infection.
- Concentric circles (rings within rings) are characteristic of fungal, not insect, damage.
- Fungal damage typically starts at the bottom leaves and progresses upward.
- Insect damage appears as light tan spots or chewed areas, often on leaf undersides.
Principles of Managing Fungal Diseases
- Begin spraying as soon as you notice fungal spots; early intervention is key.
- Maintain a routine spray schedule for effective control.
- Only spray affected tomato plants; most fungal issues are plant-specific.
- Remove diseased bottom leaves after spraying to reduce disease spread.
- Test spray on a few leaves, wait 48 hours for damage; only proceed if safe.
Organic and Non-Organic Sprays
- Three organic sprays: baking soda, wettable sulfur, and copper fungicide.
- One non-organic spray: Daconil (waterproof, longer-lasting).
- Baking soda (1-2 tbsp/gallon water) raises leaf pH, making it inhospitable to fungi.
- Wettable sulfur (1-2 tbsp/gallon water) lowers leaf pH, disrupting fungal growth.
- Copper fungicide disrupts fungal reproduction; follow label mixing instructions.
- Reapply baking soda and sulfur sprays every 7-14 days, or every 5-7 days during outbreaks or after rain.
- Use copper or sulfur sprays on larger fruiting plants; for tomatoes eaten off the vine, prefer baking soda.
Monitoring and Routine
- Journal fungal issues to track timing and effectiveness of treatments each season.
- No spray guarantees elimination, but consistent management prevents serious damage and crop loss.
- Choose spray based on harvest timing and personal preference (organic vs. non-organic).
Key Terms & Definitions
- Fungal Issue — Plant disease caused by fungi, identified by brown spots with yellow halos.
- Wettable Sulfur — Organic fungicide powder that lowers leaf pH to prevent fungal growth.
- Baking Soda Spray — Solution that raises leaf pH, hindering fungal reproduction.
- Copper Fungicide — Organic chemical that kills fungi by disrupting their life cycle.
- Daconil — Synthetic, waterproof fungicide providing extended protection.
Action Items / Next Steps
- Test chosen spray on a few leaves; wait 48 hours for any negative reactions.
- Begin spray routine at the first sign of fungal spots.
- Remove and discard affected bottom leaves post-spraying.
- Keep a journal tracking fungal outbreaks and spray schedules.