Mealybugs
White, woolly tufts in leaf axils, along veins and on roots, hiding oval, white-powdered insects of 3–5 mm. The plant becomes sticky, turns yellow and grows poorly.
Mealybugs mainly affect houseplants and greenhouse plants in warm, dry air, and often arrive on a new plant.
What can you do?
- Isolate the affected plant so the mealybugs can’t spread to others.
- Dab off the tufts with a cotton bud dipped in surgical spirit and repeat weekly.
- Rinse the plant and spray with an insecticidal soap; check the leaf axils and under the rim of the pot too.
- In a greenhouse, you can release the predatory ladybird Cryptolaemus. If the plant is badly infested, throw it away.
Prevention
Check new plants carefully before placing them with others, and inspect the leaf axils regularly.