Brown Spots on Tomato Leaves?
The four common causes — and how to tell which one you have.
Brown spots on tomato leaves are almost always a fungal or bacterial disease: most commonly early blight (brown target-ring spots low on the plant), septoria leaf spot (many small dark-bordered spots), or bacterial spot — while fast-spreading grey-brown blotches can mean late blight. The pattern tells you which: concentric rings point to early blight; tiny black dots in tan centres point to septoria; greasy spreading blotches mean act fast. Snap a photo below for an instant diagnosis and the exact fix.
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The 4 causes, compared
| Cause | How to spot it | Fix |
|---|---|---|
| Early blight | Brown target-ring spots with a yellow halo, on older/lower leaves first | Remove affected leaves, mulch to stop soil splash, spray copper or chlorothalonil |
| Septoria leaf spot | Many small circular spots — dark border, tan centre with tiny black dots | Strip infected lower leaves, improve airflow, apply a copper/chlorothalonil fungicide |
| Bacterial spot / speck | Small dark greasy spots (often with a yellow halo) on leaves and fruit | Copper spray, remove infected tissue, never water overhead |
| Late blight | Large irregular grey-brown greasy blotches, white mould underside, spreads fast | Act immediately — destroy affected plants; it can wipe out a crop in days |
FAQ
- Why does my tomato have brown spots on the leaves?
- Most often it's early blight (brown target-ring spots low on the plant) or septoria leaf spot (many small dark-bordered spots). Both are fungal and favoured by warm, wet, humid weather and splashing soil.
- How do I treat brown spots on tomato leaves?
- Remove the affected lower leaves, improve airflow, keep water off the foliage, and apply a copper or chlorothalonil fungicide early. Mulch the soil to stop rain splashing spores back up onto the plant.
- Will tomato brown spots spread to the fruit?
- Yes — bacterial spot and late blight attack the fruit too, and early blight can cause stem and fruit lesions. Treat the leaves early to protect the crop.