Houseplant Pests – Mealy Bugs

These soft, fiat, wingless insects are covered with mealy white wax.
Their bodies are also fringed with white waxy projections.
Consequently they are easily recognisable when they are feeding on exposed parts of the plant. Unfortunately they have the habit of finding hidden corners such as curled up leaves, the sheaths of leaves and bud axils where they are difficult to detect. Both adults and young suck sap from the plant, weakening and stunting its growth. Mealy bugs also excrete masses of sticky honeydew which quickly becomes covered with sooty black moulds. Infested plants make poor growth and, in severe attacks, the leaves turn yellow and fall.

Plants attacked

Mealy bugs feed on a wide range of plants but those most in danger of attack include azalea, cacti, citrus, Codiaeum, ferns and Hedera (ivy).

Control measures

Light infestations can be wiped off with a moistened swab of cotton wool or with a moist paintbrush. Heavy infestations can be dealt with most easily by repeat sprays with an insecticide containing either malathion or pirimiphos-methyl. Ferns, cacti and succulents are sensitive to insecticides so these are best treated by the more laborious method of hand swabbing.