Tomato leaves show trouble early, if you know what to look for. This guide covers the tomato leaf diseases farmers and gardeners meet most, how to tell them apart and how to treat them. Always confirm serious outbreaks locally and use only products registered for tomato where you farm.
In short
- Spot pattern and where on the plant it starts identify the disease.
- Wet leaves, crowding and poor airflow favour most tomato leaf diseases.
- Water at the base, stake plants, remove infected leaves and rotate crops.
- Late blight moves fast. Act the same day you suspect it.
Common tomato leaf diseases
| Disease | What you see | Favoured by | First step |
|---|---|---|---|
| Early blight | Brown spots with concentric rings on older, lower leaves | Warm, humid weather, stressed plants | Remove lower leaves, mulch, rotate crops |
| Late blight | Large greasy dark patches, white mould underneath in humid air | Cool, wet weather | Act at once; remove infected plants and get local advice |
| Septoria leaf spot | Many small round spots with grey centres and tiny black dots | Wet leaves, splashing water | Remove affected leaves, avoid overhead watering |
| Leaf mold | Yellow patches on top, olive-green mold underneath | High humidity, closed greenhouses | Improve ventilation |
| Bacterial spot | Small dark water-soaked spots, often with a yellow halo | Warm, wet weather, splashing | Use clean seed, avoid working in wet plants |
| Yellow leaf curl | Upward-curled, yellow, small leaves; stunted plants | Spread by whiteflies | Control whiteflies, remove infected plants |
How to prevent tomato leaf diseases
- Water at the base early in the day, not over the leaves.
- Stake or trellis so air moves through the plants.
- Mulch to stop soil splashing on leaves.
- Rotate away from tomato, potato and pepper for a few seasons.
- Use healthy seedlings and resistant varieties where available.
- Clean tools between plants and fields.
Treating an outbreak
Remove and dispose of the worst leaves, improve airflow and cut leaf wetness first. If a spray is needed, choose a product registered for tomato in your country and follow the label. Organic options exist for some diseases; ask your adviser which suits your rules.
How Famo AI helps
Take a photo of the leaf and the Famo AI scan suggests the likely disease, shows how sure it is, explains the cause and offers organic and conventional options you can add to your task plan. The scan needs an internet connection.
Get Famo AI on Google Play or try the live demo, no sign-up needed.
Frequently asked questions
Why are my tomato leaves turning yellow with brown spots?
Common causes are early blight, septoria, a nutrient shortage or watering stress. The spot pattern tells them apart; use a clear photo and check your soil.
Is late blight dangerous?
Yes. It can destroy plants in days in cool, wet weather, so act the same day you suspect it.
Can I eat tomatoes from a diseased plant?
Fruit from plants with leaf spots is often fine if it looks healthy, but follow local food-safety advice and any product pre-harvest intervals.
