Beech scale
Beech scale produces a grey-white waxy powder which can be obvious on beech trees. This does little harm to the trees.
Quick facts
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?
Scale insects are sap sucking true bugs belonging to several families in the Hemiptera. Typically the adults are immobile having a flattened or raised appearance, with no visible legs. They often look like a ‘scale’ on a leaf or stem, many species produce a white wax often covering egg masses. There are more than 100 species found in Britain, 26 of which have been introduced. More than 25 species can be found in gardens or on houseplants.
Symptoms
Individual scales are about 1 mm long but populations are usually detected by the grey-white waxy powder that colonies produce.
There is no honeydew produced and little direct damage is caused but affected trees may become more susceptible to beech bark disease, a combination of the scale and a canker fungus (Nectria coccinea) (Forest Research information).
Management
Biology
Beech scale is a 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.
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