Can I use household soap to kill the pests?

Avoid using harsh dish soaps as they can burn the leaves. Stick to insecticidal soap or a mild horticultural soap.

Will these pests kill my castor bean?

If left untreated, a heavy infestation can weaken the plant and cause leaf loss. Early intervention usually saves the plant.

Castor bean: pests, causes and fixes

Check these first

Inspect the undersides of leaves for webbing.
Look for tiny moving dots on the stems.
Check if the air around the plant is very dry.

Likely causes

Spider mites
Most likely
How to tell: You will see fine, silky webbing between leaves and tiny yellow stippling on the foliage surface. These pests thrive in hot, dry air.
What to do: Wipe the leaves down with a damp cloth to remove the mites. Spray the plant with insecticidal soap every 5 to 7 days until the infestation clears.
Aphids
Possible
How to tell: This is less common for this plant, usually caused by poor air circulation or nearby infested plants. Look for clusters of small green or black insects on new growth.
What to do: Blast the aphids off with a steady stream of water from your hose. If they persist, apply neem oil to the affected areas once a week.

Find out what's wrong with your castor bean

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

Worry if the leaves start turning yellow or dropping rapidly. A few mites are manageable, but a full colony can stunt growth quickly.

Stopping it coming back

Keep the humidity up by misting the leaves occasionally and ensuring the plant has good airflow. Regularly wiping leaves keeps them clean and pest free.

Keep your castor bean healthy from here

Save your plant in Pocket Botanist and you get care reminders timed for this plant, plus a care history that shows what worked. Identification and a health check are free.

Get the app · Or check it from a photo now, free

Questions people ask

Can I use household soap to kill the pests?: Avoid using harsh dish soaps as they can burn the leaves. Stick to insecticidal soap or a mild horticultural soap.
Will these pests kill my castor bean?: If left untreated, a heavy infestation can weaken the plant and cause leaf loss. Early intervention usually saves the plant.

Why are there pests on my castor bean plant?