Is the sticky stuff harmful?

The sticky stuff is honeydew, which is waste from the scale. While not directly harmful, it attracts ants and leads to sooty mold.

Can I use pesticides?

It is better to use horticultural oil or insecticidal soap. These are effective against scale without harming beneficial insects.

Why are there pests on my Chinese wisteria?

Check these first

Inspect the undersides of leaves and stems for small bumps.
Touch the leaves to see if they feel sticky.
Look for black dust on the foliage.

Likely causes

Wisteria Scale
Most likely
How to tell: You see small, round, brown bumps on the stems and a sticky substance on the leaves.
What to do: Scrub the stems with a soft brush and soapy water to remove the insects. For heavy infestations, apply horticultural oil in early spring before the buds break.
Sooty Mold
Possible
How to tell: A black, powdery coating appears on the leaves, usually following a scale infestation.
What to do: Wash the leaves with a gentle spray of water to remove the mold. Treat the underlying scale infestation to stop the mold from returning.

When to worry

If the scale covers the entire vine, it can weaken the plant significantly. Treat it early to prevent stunted growth.

Stopping it coming back

Keep your wisteria healthy with proper watering and pruning, as stressed plants are more attractive to pests.

Not sure which one it is? Photograph your wisteria.

This page lists the usual causes. Pocket Botanist looks at your actual leaf 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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Questions people ask

Is the sticky stuff harmful?: The sticky stuff is honeydew, which is waste from the scale. While not directly harmful, it attracts ants and leads to sooty mold.
Can I use pesticides?: It is better to use horticultural oil or insecticidal soap. These are effective against scale without harming beneficial insects.