Will aphids kill my tree?

Usually no, but a severe infestation can weaken a young tree. Keep an eye on the health of the new growth.

Does the sticky stuff hurt the leaves?

The honeydew itself is harmless, but it encourages black sooty mold to grow, which can block sunlight from reaching the leaf surface.

Japanese zelkova: pests, causes and fixes

Check these first

Inspect the undersides of young leaves for small insects.
Look for sticky honeydew on the foliage.
Check for ants traveling along the branches.

Likely causes

Aphid infestation
Most likely
How to tell: You will see clusters of tiny green or black insects on new growth and a sticky substance called honeydew on the leaves below. Sooty mold often grows on this sticky residue.
What to do: Spray the tree with a strong stream of water to knock the aphids off. If the infestation is heavy, apply insecticidal soap or neem oil according to the label instructions.
Ant activity
Possible
How to tell: Ants are often seen crawling up and down the trunk to farm the aphids for their honeydew. They protect the aphids from predators.
What to do: Focus on removing the aphids first, as the ants will leave once their food source is gone. You can also wrap a sticky barrier around the trunk to stop ants from climbing.

Pests on other plants

Find out what's wrong with your japanese zelkova

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.

When to worry

A few aphids are normal and usually handled by ladybugs. Worry if the tree shows signs of stress or if the honeydew is causing heavy sooty mold coverage.

Stopping it coming back

Encourage beneficial insects like ladybugs and lacewings to visit your garden. Avoid over fertilizing, as excess nitrogen attracts aphids.

Japanese zelkova: pests? Check yours with a photo

Every plant is a little different. Take a photo of your japanese zelkova 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

Will aphids kill my tree?: Usually no, but a severe infestation can weaken a young tree. Keep an eye on the health of the new growth.
Does the sticky stuff hurt the leaves?: The honeydew itself is harmless, but it encourages black sooty mold to grow, which can block sunlight from reaching the leaf surface.

Guides to these causes

Aphids

Why are there sticky spots on my Japanese zelkova leaves?

Check these first

Not sure what's wrong with your japanese zelkova?