Adult (resting)
9-11 mm long, forewings pale ochreous yellow each with four darker spots and scattered darker scales. Hindwings paler. Lie still when disturbed (e.g. by beating) characteristically scuttling round on its back sporadically.
Egg
Very pale green becoming orange-brown prior to hatching. Oval, 0.7 mm long and 0.4 mm wide. Eggs can be laid on the undersides of leaves and on dead leaves in the tree.
Larvae
Up to 10-13 mm long; purplish-brown and shiny, lighter underneath. With a darker head and prothoracic plate, rather plump.
Other pests with which Blastobasis may be confused
Larvae of several leaf-rolling tortrix moths cause similar, though less severe damage, including larvae of the summer fruit tortrix moth, Adoxophyes orana.
- The purplish-brown colour of Blastobasis larvae is distinctive.