Beech scale

Beech scale produces a dirty white waxy powder which can be obvious on beech trees. Although it is unsightly and may cause alarm it does little harm to the trees.

Beech scale (<EM>Cryptococcus fagisuga</EM>) on Beech (<EM>Fagus sylvatica</EM>)

Quick facts

Common name  Beech scale
Scientific name Cryptococcus fagisuga
Plants affected Beech trees (Fagus sylvatica
Main symptoms Dirty waxy powder on trunk and larger branches
Caused by Sap sucking scale insects 
Timing Summer

What is beech scale?

Beech scale, also known as felted beech coccus, is a scale insect that feeds on the sap of beech (Fagus sylvatica) trees. It is found in colonies in crevices of the bark of the trunk and larger branches.

Symptoms

Individuals are about 1mm long but infestations are usually detected by the dirty white waxy powder that colonies produce.

There is no honeydew produced and little direct damage caused but affected trees may become more susceptible to beech bark disease. 

Control

As this insect usually causes little direct damage to trees control is not necessary. This is fortunate as it is not practical to treat the large trees that it often infects.

Biology

Beech scale is parthenogenetic (reproducing without the need for males) scale insect with one generation year.

During the summer each female lays clusters of up to eight eggs under the protective white waxy wool like substance. The eggs hatch by late summer and the nymphs settle to feed in bark crevices. They overwinter as nymphs becoming adults in early spring.

Advertise here

Gardeners' calendar

Advice from the RHS

Find out what to do this month with our gardeners' calendar

Advice from the RHS

Did you find the advice you needed?

RHS members can get exclusive individual advice from the RHS Gardening Advice team.

Join the RHS now

Discuss this

for the site or to share your experiences on this topic and seek advice from our community of gardeners.

Get involved

We're a UK charity established to share the best in gardening. We want to enrich everyone's life through plants, and make the UK a greener and more beautiful place.