Pests of box
This insect causes the leaves to become cup-shaped and in spring there are splashes of a waxy white material on the foliage which can also be blown around in the wind. In most cases this insect can be tolerated as it has a very limited effect on plant growth. Visit the Box sucker profile for more information.
The caterpillars of this moth can completely defoliate plants. It is prevalent in parts of England and has spread into Wales and Ireland. For more information and to submit reports of this insect visit the box tree caterpillar profile.
Box leaf-mining gall midge
The box leaf-mining gall midge, Monarthropalpus flavus, is uncommon in Britain but occasionally feeding damage is observed. This tiny fly deposits its eggs in the new leaves during late April - May. The larvae feed inside the foliage, causing a yellowish discolouration on the upper leaf surface. The lower leaf surface develops a slight swelling in the area affected by the larva's feeding. The yellow larvae are up to 3mm long and they feed inside the leaves during summer – winter before pupating within the mines in spring. Several mines can develop in a leaf and heavily damaged ones often drop off.
Whilst the damage caused can be unsightly it rarely affects the vigour of plants and it can usually be tolerated.
Mussel scale, Lepidosaphes ulmi, is a sap-sucking insect that is found on a range of woody plants, including box, apple, hawthorn, ceanothus, cornus and cotoneaster. The blackish-brown shells or scales are shaped like mussels, up to 3mm in length, and are attached mainly to the bark but sometimes they spread to the foliage. Heavy infestations can result in plants dying back. Visit the Mussel scale profile for more information.
Box red spider mite
A fine whitish mottling on the foliage of box plants can be caused by the box red spider mite, Eurytetranychus buxi, which is a mite that is specific to box. This tiny creature feeds by sucking sap from the undersides of the leaves, particularly during spring and early summer. By late summer it dies out and the mite overwinters as eggs, which are laid on the stems and underside of leaves.
Box tree red spider mite is difficult to control. Fortunately, although the mottling may be considered unsightly, this mite does not cause serious damage to the plants and so it can be tolerated.
Fluted scale, Icerya purchasi, is a sap-feeding insect which, until recently, was largely confined to heated greenhouses. It still an uncommon problem, especially on outdoor plants, however in recent years it has become more widespread. This insect has a very wide range of host plants, including box, and heavy infestations can cause a lack of vigour. The adult scales are flat, oval insects about 4-5mm long and reddish brown in colour. The females deposit their eggs amongst mounds of white waxy fibres that have a grooved appearance, these can be found on the stems and foliage. The scales excrete a sticky honeydew on which black sooty moulds can grow. Visit the Fluted scale profile for more information.