Mealybugs can be a serious pest problem of numerous plants. Although they are usually only present on plants growing indoors or under cover.
Mealybugs can be present in the house, the conservatory, the sun lounge or the greenhouse, few plants will escape its attention. About 4mm long, their soft bodies are a greyish-white or pink. They secrete a fluffy white, waxy substance that protects their bodies and hides their eggs. They suck sap so are most susceptible to systemic insecticides that get inside the plant.
Look for colonies on the underside of leaves and on plant stems. Like most sap feeders they excrete a sugary honeydew, which makes the surface of leaves on to which it drops very sticky. A black sooty mould grows on this sticky substance.
Treatment and control
Small outbreaks can be wiped off the plants with a damp sponge or kitchen towel - but check regularly for re-infestations.
Spray with a general insecticide
As the waxy coating provides protection against contact insecticides, systemic insecticides are the best ones to use.
A biological approach
Introduce a predatory beetle (Cryptolaemus montrouzieri), which will eat mealybugs. This is available from numerous mail order biological control suppliers.