Common house plant pests: Aphids

Description:
Commonly called plant lice.

Aphids, common house plant pest

Detection:
Check the undersides of leaves, new shoots and buds for an oval shaped insect which grows to about 3mm long with disproportionately long legs and antennae; some species also have wings. Aphids may be green, pink, brown, white, black, yellow, red or grey. They live in small colonies or groups and often have white "shells" (cast-off skins) scattered among the living insects. Aphids suck out juices from the plants, causing stunted growth, and distortion of buds and leaves which if left untreated will cause the affected area to curl and die. They also excrete a sticky honeydew which could attract a black sooty mould. The more difficult aphids to detect feed from the roots. Although, fortunately, they are unusual on house plants.

Control:
Remove as many as possible by hand with a soft brush then take the plant and swish it upside-down in a weak solution of soapy water (preferably non-detergent). Be careful not to contaminate the soil with soap and cover the top of the pot with a plastic bag in order to prevent soil falling out. Swab the leaves with a soapy cloth and then rinse with clear tepid water. A tough plant may be rinsed with the garden hose paying particular attention to the underside of the leaves. For persistent infestations, take the plant into a well ventilated area, preferably outside, and spray the plant with one of the insecticides that are legal to use where you live. Aphids are becoming resistant to some of the commonly used chemicals, so check with your local garden centre or agricultural college.

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