Bacterial Leaf Spot
Small dark spots that look wet or greasy at first, then dry to brown or black. Where a leaf has strong veins the spots go squared-off and angular because the veins stop them spreading, and they never carry the concentric target rings you see in early blight.
Disease checklist
Four things to look for. If most of them match what you are holding, you are in the right place.
What gets rid of it
Gentlest option first. For most backyard cases the first one is enough, so try these in order and stop as soon as it works. If you do spray something, the product label tells you how — please read the notice further down.
1Stop overhead watering
Water the soil at the base of the plant in the morning so the leaves never stay wet.
drip irrigation kit gardenTry this first2Stay out of wet plants
Do not prune, tie or pick while foliage is wet; you carry the bacteria on hands and clothes.
3Space plants wider
Give each plant enough room that air moves through and leaves dry off after a rain.
4Buy clean seed and resistant varieties
Order certified disease-free seed and pick varieties listed as resistant to bacterial spot.
bacterial spot resistant tomato seed5Rotate three to four years
Keep tomatoes and peppers out of the same bed for at least three years and clear the old debris in fall.
6Copper only protects
A copper spray can slow new infection on healthy leaves but will not clean up leaves already spotted. Follow the product label.
copper fungicide garden
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Which plants get bacterial leaf spot
Every plant we cover that gets bacterial leaf spot, grouped by type — tap any one to open its page. A note beside a plant came from that plant’s own entry, because the same disease can be a minor nuisance on one plant and a serious problem on another. Plenty of plants we do not cover get it too.
Plant families hit hardest
Related plants often share the same problems, so if one plant in a family has it, check the others. The largest group here is Rosaceae, with 3 of the 10 affected plants.
- Rosaceae3 plants
- Asteraceae2 plants
- Solanaceae2 plants
When to treat
Act the first week you see spots, because the bacteria travel in splashing water and every rain pushes them further through the planting.
Timing only — the label is the law
This page tells you when to watch for bacterial leaf spot and when treating is worth considering. It is not a recommendation to apply any particular product. Read and follow the product label before you spray — under federal law the label is the legal instruction, and using a pesticide against it is illegal.
- Check the pre-harvest interval. Every product that’s cleared for an edible crop sets a minimum number of days between spraying and picking. Find it on the label before you spray anything you intend to eat.
- Check the re-entry interval before you or anyone else works in the treated area again, and use the protective equipment the label names.
- Confirm the product is registered for your crop in your state. This page groups many different crops together, and a product legal on one of them is not legal on all of them — state registrations differ too. Your state pesticide agency or local extension office can confirm both.
- Rates and mixing instructions come from the label, never from us. We don’t publish them because they differ by product and formulation.
Other problems on the same plants
If a plant gets bacterial leaf spot, these are the problems it most often gets as well, so they are worth checking for while you are out there. They tend to appear together; one does not cause another.