Bacterial leaf spot of lettuce
Small water soaked spots turn angular and black between the veins, dry out papery, and heads can rot from the outer leaves.
Crops it strikes
What you see
When to act
Check the outer leaves every week, more often after rain. Start copper sprays only when the first small, angular, black edged spots appear in a wet spell. In dry weather the disease stalls on its own.
What to spray
Active ingredients only, never brands. The FRAC group tells how it works: switch to a different group next time, so the disease does not learn to survive it. Spray only when the damage is worth the cost, and only with products registered with the Fertilizer and Pesticide Authority for your crop. Follow the label. The Shopee and Lazada links only show who sells something with that active ingredient, not a recommendation of any seller or product.
How to prevent it
- Sow clean seed from a trusted seller. The bacterium travels in lettuce seed.
- Water at the base or by furrow, not over the leaves, and do not work the beds while they are wet.
- Rotate for at least a season away from lettuce, and plow under or remove old lettuce right after harvest.
- Space the plants so leaves dry fast, and grow a tolerant variety where one is sold.
- Pull and remove plants with many spots so rain does not splash the bacteria to their neighbors.
Where this comes from
Not sure it is this one?
Many diseases look alike. Send a photo to Anee, the smart farm technician in anee.io. She reads it with your crop, its age and the weather, and tells you what it most likely is and what to do first. In Tagalog or English.