Pepper brown spots on leaves
There are 3 common causes, and they need completely different responses — so working out which one you have matters more than treating quickly.
None of them will normally kill the plant.
Check these two things first
- Push a finger into the soil, two knuckles deep. Wet soil plus a wilting plant means too much water, not too little — and it is the commonest reason a plant is dying. Dry soil plus crisp leaves means the opposite. The leaves look nearly identical either way, so the soil is what tells you.
- Turn a damaged leaf over. Half of all diagnoses live on the underside: fuzz means downy mildew, fine webbing means spider mites, clusters of insects mean aphids. Nothing on the top of a leaf is as informative.
Most garden problems are cosmetic and resolve without treatment. Reach for a spray last, not first.
The 3 causes, and how to tell them apart
1.Bacterial Leaf Spot
TreatableBacterial disease
Small dark spots that look wet or greasy, often with angular edges because they stop at the leaf veins, sometimes surrounded by a yellow halo. In humid weather the spots look water-soaked; in dry weather the centres fall out leaving small holes.
How to know it is this one
Greasy, water-soaked appearance, especially in the morning.
2.Early Blight
TreatableFungal disease
Brown spots about the size of a pencil eraser with concentric rings inside them, like a tiny archery target. The tissue around each spot turns yellow, and affected leaves eventually go fully yellow and drop.
How to know it is this one
Concentric rings inside each brown spot — the bullseye is the giveaway.
3.Sunscald
Mostly cosmeticGrowing conditions
On fruit, a pale whitish or yellow patch on the shoulder facing the sun, which becomes papery, sunken and sometimes greyish as it dries. On leaves, bleached or brown patches on the most exposed surfaces rather than at the edges.
How to know it is this one
Damage on the side facing the sun, not the blossom end or stem end.
Still not sure?
The diagnostic key adds two more questions — which part is affected and where the trouble started — and those usually settle it.
Run the diagnostic key