Latin name: Choristoneura rosaceana
Reason for Concern:
1) Dominant leafroller species in caneberries in British Columbia and northern Washington. Egg hatch timing makes it less of a problem in southern growing regions.
2) In the south larvae usually appear after harvest of primary varieties and only a potential problem in late ripening blackberries.
3) Foliar webbing and feeding damage is rarely economic. Larvae are a potential harvest contaminant.
Larvae are yellowish green caterpillars, up to 1”, with a dark brown or black head and shoulders. When disturbed, they wiggle backwards and drop to the ground on a silken thread. Larvae form protective nests in webbed rolled leaves during pre-bloom and harvest time. Some larvae feed within berries and may not be noticed until harvest. Adult moths, predominant during pre-harvest, have dark brown bands running at oblique angles across the wings.
Obliquebanded leafrollers overwinter as young larvae, often between canes. They feed on new leaves, buds and rolling leaves, from April to June, then pupate and emerge as moths. Moths mate and lay eggs on leaves and canes. Hatched leafrollers feed on foliage and ripe fruit and can contaminate harvested berries.
- Place pheromone traps in fields beginning in late April or May and check weekly. Change lures every 28 days and trap bottoms when debris (organic material) limits the usefulness of the trap. Count and record. Scrape trap bottom and note date on trap when bottoms and lures are changed.
- As the pheromone attractant for Orange Tortrix and Obliquebanded Tortrix is very similar, it is necessary to distinguish between the two while trapping. Orange Tortrix is considerably smaller than the Obliquebanded, and the Obliquebanded generally has much thicker, more pronounced, diagonal lines across its wings. Carnation Tortrix will also sometimes be caught and is easily discernible by its bright orange coloring on the underside of its wings.
- About a week after peak flight, begin scouting for larvae using a beating tray in several random locations throughout field. The Orange Tortrix larva will appear light brown to yellow green, and will appear full grown at ¾” (2-3cm) long. When agitated, it will wiggle vigorously backwards and drop to the ground on a silken thread. Orange Tortrix larvae differ from Obliquebanded larvae in that the Orange Tortix larvae will have a much lighter colored head than Obliquebanded which has a brown or black head.
- Search 10 leaf tips in at least 4 areas of the field for indication of larvae (rolled leaf often at tip of canes). Identify, record number and destroy. Change areas per visit in order to cover field.
- Leafrollers are a minor pest in blueberries, however, there may be low tolerances for blueberry exports to certain countries.