A problem on an annoying scale

Q

My euonymus havebeen devastated by tiny white mites. What can I do to get rid of them?

Mrs V C Ransom, Stamford, Lincs

AThe pests are probably euonymus scale. They clamp down on the plant, sucking sap and causing pale mottling on the leaves, which eventually turn yellow and fall. Such infestations weaken the plant causing dieback.

The males are white, elongated oval shaped and measure 1-2mm. They appear on the underside of leaves and sometimes on top.

The larger, brownish oyster-shellcoloured scales are the females. When scales first hatch they are quite mobile, but then their hard shells form and they become fixed to one spot.

Males, females and juveniles may all be present at the same time and are particularly prevalent from May to August.

Deal with them using insecticide, spraying in June and September to control each year’s two generations. Organic sprays using plant oils (Bug Clear for Fruit and Veg) can be used, with several applications.

More persistent pesticides, including Bayer Ultimate Fruit and Vegetable Bug Killer or Westland Resolva Bug Killer, may give better results. I would also cut back stems to healthy growth.