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Key lime · Citrus aurantiifolia

What are these spots on my Key lime tree leaves?

Spots on citrus leaves can range from harmless fungal issues to serious bacterial infections. Identifying the pattern is key to saving your tree.

Not sure it's this? Check a photo of your plant for free

spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Check if the spots have a yellow halo.
  2. Examine the fruit for similar markings.
  3. Ensure the leaves are not staying wet after watering.

Likely causes

  1. Citrus Canker

    Possible

    How to tell: Small, raised, tan or brown spots appear on leaves, stems, or fruit. They often have a yellow halo around them.

    What to do: Prune away severely infected branches using sterilized shears. Keep the foliage dry by watering at the base of the plant instead of overhead.

  2. Fungal Leaf Spot

    Possible

    How to tell: Dark brown or black spots with irregular shapes appear on the leaves. This usually happens when the tree stays wet for too long.

    What to do: Increase air circulation around the tree by moving it to a spot with better airflow. Remove fallen leaves from the soil surface to prevent spores from spreading.

Leaf spots on other plants

Find out what's wrong with your key lime

The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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When to worry

If the spots are spreading rapidly or causing fruit to drop, it is a serious issue. Minor cosmetic spotting is usually not a threat to the tree.

Stopping it coming back

Water the soil directly rather than wetting the leaves. Ensure the tree gets plenty of direct sunlight to help the foliage dry quickly.

Key lime: spots? Check yours with a photo

Every plant is a little different. Take a photo of your key lime and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.

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Questions people ask

Is citrus canker contagious?
Yes, it spreads easily through wind and water splashes. Isolate the plant if you suspect it has canker.
Can I eat the fruit if the tree has spots?
If the spots are just on the rind, the fruit is generally safe to eat. However, do not share the fruit if the tree has a confirmed bacterial infection.

Guides to these causes

More problems with Key lime

Back to the Key lime guide

This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.