Beech beetles. Computer illustration of a beech scale (Cryptococcus fagisuga) larva and a beech (Fagus sp.) tree, with an inset showing the characteristic 'scale' pattern left by the insect on the bark of the host tree. The larvae of the beech scale insect infest beech trees and are associated with the transmission of beech bark disease as the holes they punch in the bark allow entry of pathogenic fungi.