Plant guide:🍅 Tomato
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⚠ CriticalOne-sided leaf browning and curling with stem streaking — bacterial canker, most often introduced via infected seed.
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Fungal
Bacterial Canker on Tomato
Commonly affects: Solanum lycopersicum (Tomato)
Leaf margins brown and curl upward starting from the bottom of the plant, often on just one side of a leaf or stem. Stems may develop dark streaks or open cankers, and fruit can show small white-haloed 'bird's-eye' spots.
Potential Causes
- 1Clavibacter michiganensis bacteria, often introduced via infected seed or transplants
- 2Wounds from pruning, tying, or wind damage giving the bacteria entry points
- 3Working around wet plants, spreading bacteria via hands and tools
Solution Steps
- 1Remove and destroy severely affected plants — there is no cure once canker is established.
- 2Disinfect tools with a 10% bleach solution between every plant when pruning or suckering.
- 3Avoid working around plants when foliage is wet.
- 4Rotate away from tomatoes for at least 2-3 years in beds where canker has appeared.
Prevention Tip
Buy certified disease-free seed or transplants — bacterial canker is most often introduced this way rather than developing spontaneously in a garden.
