In Canada, this species is restricted to south coastal British Columbia; it also occurs south along the coast to California and throughout Europe.
Damage, symptoms and biology
Ditula angustiorana is a common solitary defoliator.
Mature larvae up to 14 mm long. Head, brownish yellow with distinct ocellar area and lateral bar on cheek. Thoracic shield usually yellowish, grading to brownish laterally. Body, yellowish green above spiracular line, creamy yellow below. Faint green middorsal stripe.
This species overwinters as a young larva. Larval feeding resumes in spring and continues until June. Pupation occurs in June, and adults emerge from June to July. Eggs are laid in shingle-like masses on host foliage.
Canadian Forest Service Publications
Diet and feeding behaviour
: Feeds on the leaves of plants.
- Free-living defoliator: Feeds on and moves about freely on foliage.
Information on host(s)
The principal coniferous hosts of Ditula angustiorana are Douglas-fir, western yew and common yew; other hosts include Garry oak, ivy, boxwood and apple.