19 Jan Mealybug


Mealybugs are one of the harder common insect pests to eradicate in either the garden or in potted plants. Their pale pink bodies are covered in waxy threads and powdery wax and often get diagnosed as a fungal problem.

Damage Caused:

Mealybugs suck on the plants sap system and weaken the plant considerably. They can generally be found on concealed areas of plants such as where leaves sheath around each other (eg. Centre of Clivea, Agapanthus, Flax) or in forks of plant growth. They can also live in the potting mix of potted plants where they adhere to the roots. As they produce a waxy substance they are often mistaken for a fungal disease.

Ants can generally be found around Mealybugs, protecting them from natural predators such as ladybirds in return for a feed on the sugary substance (honey dew) they excrete from their bodies.

It is also this honey dew that feeds a fungus called ‘sooty mould’ that blankets the leaves in a back, sooty film. Removal of the mealybugs will remove the source of the honey dew and thus diminish both.


Green: Oil sprays can beneficial in reducing numbers (eg. Eco-Oil, Pest Oil) sprays are useful for both vegetable and ornamental gardens. Oil sprays work by smothering the pests, blocking their breathing (which they do through their body) and killing them. Application to the entire plant (including undersides of leaves is crucial when using these types of products, as they require you to get the spray onto every pest for successful control. Just a few sheltered pests re-populate a plant quickly if the conditions are right.

NB Do not apply oil sprays in temperatures exceeding 25°C as this will likely burn foliage.

Orange: Generally only ornamentals are treated with systemic insecticides (eg. Confidor, Maxguard),which penetrate into the plants sap system which the pests feed on. They are highly efficient at killing these pests and last on average two weeks in the plants system. With this pest a re-application is recommended after two weeks. As they are systemic the spray does not have to make contact with the pest itself to work and insects can be killed in areas of the plant not reached by the spray (though thorough application is recommended)

NB Care should be taken when spraying these above chemicals is they harm foraging bees. As a rule I only use these on plants that are not currently in flower to avoid the risk to bees that are so vital in the garden. Saying that these sprays are invaluable for treating pests in situations such as hedging where contact with individual pests is not always possible.

Red: Not required for this pest.



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