Oak leafshredder

French common name: Tordeuse printanière du chêne
Scientific name: Croesia semipurpurana (Kraft)
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Tortricidae

Distribution

Eastern Canada

Damage, symptoms and biology

Very early in May, at bud break, the leaves expanding from buds mined by oak leafshredder larvae are riddled with small holes. The larvae continue feeding on the foliage and tie leaves together with silk webbing. These leaves turn brown, resulting in thin crowns. In severely infested trees, significant growth loss occurs and several years of defoliation may result in tree mortality.

When they reach maturity, the larvae spin down to the ground on silken threads and pupate in the litter. The presence of sulphur yellow moths flitting around the crowns of oaks in summer confirms the presence of oak leafshredder and is a sign of an infestation the following season. The eggs are deposited singly in rough bark or cracks in second- and third-year twigs, generally around the nodes. The insect overwinters in the egg stage.

Other information

The oak leafshredder is a pest primarily of mature red oak stands in eastern North America. A native species, it was first recorded in eastern Canada in 1944, in Ontario, where it subsequently caused severe damage in red oak stands between 1957 and 1975.

The insect was first recorded in Quebec in 1945. Severe infestations occurred between 1957 and 1966 in the Quebec City metropolitan area, and subsequently spread southward and westward in the province. It appeared later in the Maritime provinces, where local infestations have been recorded almost annually since the early 1960s.

Canadian Forest Service Publications

Oak leafshredder

Diet and feeding behaviour

Phyllophagous: Feeds on the leaves of plants.
- Leaftier: Ties two or more leaves together with silk threads, forming a tube in which to hide and feed.