Mealybugs are small, soft-bodied insects which feed on sap, causing plants to become stunted and foliage to become yellow. A fluffy, white substance usually appears in leaf and stem axils. Like other sap-feeding insects, mealybugs excrete large quantities of honeydew which promotes sooty moulds and ants. Roots may also be affected; this may be seen as white patches among the roots when re-potting, especially around the sides of the root ball.

The females are oval in shape and can be up to 5 mm long. They are white or whitish-pink in colour, often with white, waxy filaments trailing from their bodies. The most common species found in glasshouses are the citrus mealybug (Planoccocus citri), the vine mealybug (Planococcus ficus) and the long-tailed mealybug (Pseudococcus longispinus).


Mealy bugs can be controlled biologically in greenhouses or conservatories by using their natural enemies Cryptolaemus (mealy bug ladybirds) or Leptomastix (parastic wasps) or a combination of both. If this fails, spray with malathion, pirimiphos-methyl or apply insecticidal soap every two weeks.