The apple clearwing moth (Synanthedon myopaeformis) is a pest of apple, often only attacking old and neglected trees. Other hosts are pear, almond, peach, cherry and plum. It is widely distributed in central and southern Europe.
Life cycle and appearance of Apple clearwing moth
The adults have a wing span of 20-25 mm; the wings are mainly clear (therefore the common name) with brownish black veins and borders. The body is black with a red band across the abdomen. The larvae are up to 20 mm long and their body is slightly flattened. They are dull whitish brown and the dark central blood vessel can be seen clearly from above. The head is shiny reddish brown and retractile; young larvae are whitish and have a light brown head. The pupa is 10-13 mm long and light brown with a dark brown head.
The adults usually appear in June or July and are very active in warm, sunny weather. The eggs are laid in crevices of the trunk of host trees or at the base of main branches, often close to wounds. The larvae emerging from the eggs burrow into the tree and form irregular, winding galleries within or just beneath the bark. Development lasts around 20 months. When fully grown, in April to June of the following year, the larva pupates in a tough greyish cocoon. The pupae can be found close to the surface amongst decayed wood and masses of frass. After 2-4 weeks, the pupae comes out of the cocoon and wiggles to the surface of the bark, where the remains can be seen protruding form the exit hole after the adult has emerged.
The bark covering infested parts peels of readily and the infestation encourages invasion of fungal pathogens. Severe attacks lead to soft, blackish patches of bark from which sticky sap may exude. The apple clearwing moth usually only attacks sickly trees and is therefore usually of secondary importance.