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Caused By:-     Pseudococcus or Planococcus species of insects


There are several species of mealybug which belong to the Pseudococcus or Planococcus Genus . Most thrive in warm conditions, which is why they are not usually seen on outdoor plants in the UK.
They are active all year round on houseplants and in greenhouses and tend to live together in clusters in parts of plants where the sap flows easily, such as leaf axils or leaf sheaths. Mealybugs are sap sucking soft bodied insects, which cover themselves in a waxy white powdery like substance.
They feed on a wide variety of garden plants especially cacti or succulents, which are usually in a greenhouse or indoors. It is often easy to overlook them on cacti as the breathing pores are usually fluffy and white.
Their sap sucking activities can inhibit or damage the plant's growth and eventually kill the plants.
These pests can also transmit bacterial and fungal infections from plant to plant.
When there is a heavy infestation they also secrete honeydew which can drop on the lower leaves allowing dirt to be trapped and moulds to grow.
The adult females have flattened oval-shaped soft bodies up to 4mm in length; they are pink in colour but appear whitish due to the waxy coating on their bodies. There is rarely any flying stages, so infestations are usually from another infested plant. Therefore keep new plants them in quarantine for a period when introducing new plants and inspect regularly.
Picture from Wikimedia Commons.
See also Mealy Cabbage Aphids, Mealy Plum Aphids, Phormium Mealy Bugs, Root Mealybugs, Wooly Aphids.


Spraying with an insecticide often does not work as their waxy coat protects them. A systemic insecticide is often best as it gets into the sap and kills the pest when it ingests it. Painting them off with a solution of washing-up-liquid, methylated spirits or rubbing alcohol is a good way to eradicate them. spraying the plant with plant oils or fatty acids will help kill eggs as well as the pest. Whatever chemical control is used it is wise to test it out on a small part of the plant before covering the whole plant. Care should also be exercised when dealing with food plants. Dead leaves and prunings should be destroyed as these may harbour mealybugs or eggs. Natural enemies of this pest are ladybirds and its larvae or parasitic wasps which can be bought to control them. The ladybird and parasitic wasps need a warmish temperature and so are mainly successful from May to September. When using biological control care must be exercised when spraying so as not to kill beneficial insects.

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