Mealybugs
Mealybugs are soft insects covered in white wax that cluster in sheltered spots on houseplants, succulents and citrus. They suck sap and excrete honeydew, and hide well enough to return after treatment.
Pests
What it looks like
Look where leaves meet stems.
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Cottony clusters White, woolly masses in leaf joints and folds. -
Waxy insects Oval, segmented white insects up to 4 mm long. -
Sticky leaves Honeydew and sooty mould below. -
Root mealybug White waxy patches on roots when repotting.
How to confirm it
Tease open a white tuft.
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Insects inside
A pink or grey insect sits inside the wax.
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Hidden spots
Check leaf bases of aloes and the joints of monstera stalks.
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Check the roots
Pale patches on the rootball point to root mealybug.
What to do
Persistence wins.
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Dab with alcohol
Touch colonies with a cotton bud dipped in rubbing alcohol.
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Wash off
Rinse plants in the shower, then check every week.
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Isolate the plant
Keep it away from others until clean.
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Biological control
The ladybird Cryptolaemus controls mealybugs in warm greenhouses.
Prevent it next time
- Quarantine new plants for two weeks.
- Check leaf joints when watering.
- Repot with fresh compost if roots are infested.
What not to do
Do not expect one treatment to work; mealybugs hide, and eggs hatch after it.
In the growing guides
Where the guides mention it, with plant-specific advice.
Sources
- Mealybug, Royal Horticultural Society