Beech red spider mite

Beech red spider mite (Eotetranychus fagi) was first detected in Britain in 2004. It is specific to beech (Fagus sylvatica) and can cause extensive bronzing of the foliage.

 Beech red spider mite

Quick facts

Common name Beech red spider mite
Scientific name Eotetranychus fagi
Plants affected Beech (Fagus sylvatica)
Main symptoms Extensive bronzing of foliage
Most active Spring to autumn
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What it beech red spider mite?

Spider mites are members of the Acari (mite) family Teranychidae. They generally live on the undersides of plants, where they spin protective webs and cause damage by puncturing plant cells to feed. Some spider mites feed on a broad range of plants others have a limited host range.

Beech red spider mite (Eotetranychus fagi) is specific to beech (Fagus sylvatica) and was first discovered in the UK in 2004. Adult mites are less than 1mm in length and despite its name are normally a pale greenish yellow.

Symptoms

Infestations cause fine pale yellow mottling (bronzing) of the upper leaf surface with damage particularly concentrated along the larger leaf veins. The undersides of the leaves have black excrement spots and are littered with cast mite skins and egg shells.

Beech grown as a hedge tends to be more vulnerable to this mite than standard trees, this may be due to the warmer microclimate that can occur around and within a hedge.

It is likely to have several generations during the summer months and will overwinter on the bark as eggs.

Control

Non-chemical control

Although the damage caused by the mites can look unsightly by late summer, it unlikely to affect the long term health of infested trees. This is fortunate as it is likely to be difficult to spray a hedge effectively against this mite and infestations on established hedges and tall trees have to be tolerated.

Chemical control 

It is only feasible to treat young hedges or trees that are small enough to be sprayed thoroughly.

Products suitable for use on beech include sprays based on plant oils (considered organic e.g. Vitax Organic 2 in 1 Pest and Disease Control or Scotts Bug Clear for Fruit & Veg). These need to be applied thoroughly to the underside of the leaves.

Do not spray near plants in flower due to the danger to pollinating insects.

Inclusion of a pesticide product does not indicate a recommendation or endorsement by the RHS. It is a list of products currently available to the home gardener.

Downloads

Pesticides for gardeners (Adobe Acrobat pdf document outlining pesticides available to gardeners)

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