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
What is beech scale?
Individual scales are about 1mm long but infestations are usually detected by the grey-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, a combination of the scale and a canker fungus (Nectria coccinea) (Forest Research information).
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.
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