Damage, symptoms and biology
Damage is initially caused by the larvae, which, because the adult females lay their eggs individually at the base of buds, penetrate into swollen buds in the spring and feed on them. Later, the caterpillars devour the leaves that are not completely sprouted. In the third instar, as the name suggests, the caterpillars (pale yellow with brown heads) roll the leaves into small tubes, inside which they nourish themselves by devouring the leaf tissue or parenchyma. To identify the insects, it may be necessary to unroll the leaf and closely examine the caterpillar, because there are other leafroller species that attack hardwood trees in Canada’s forests.
These insects, reported for the first time in British Columbia in 1909, but known in Europe since 1758, are found throughout the range of birch in Canada, from southern Ontario to the Northwest Territories. They also attack trembling aspens, alders and yellow birch. Usually birch-aspen leafrollers cause sporadic, local damage and are considered a pest of secondary importance. However, infestations followed by lull periods are regularly reported in Ontario and Quebec.
Canadian Forest Service Publications
Diet and feeding behaviour
: Feeds on the leaves of plants.
- Leafroller: Hides and feeds inside a leaf or the tip of a leaf that it has rolled up into a cigar-shaped tube.