OBLIQUEBANDED LEAFROLLER (OBLR) Choristoneura rosaceana
Description:
Adults:
Tan in color, with alternating light and dark brown (oblique) bands across their forewings. Female moths are larger and more distinctively marked.
Eggs:
Dull, greenish yellow eggs are laid in flattened, overlapping masses of up to 200 on leaves. Egg mass is approximately 0.275 by 0.551 in or 7 mm by 14 mm in diameter.
Larvae:
Fully-grown larvae are 0 .75 – 1 in or 19 to 25 .4 mm long, yellowish green with brown to black head capsule.
Host:
Apples, pears, walnuts, filberts, pistachios, stone fruit, oaks, berries, grapes, hops, azaleas.
Damage:
- Larvae from overwintering generation become active in March and April, feeding on leaves and developing fruit.
- Severely damaged fruit or clusters are often aborted by trees. Those remaining are deeply scarred and deformed.
- Summer generation larvae cause the most serious damage by shallow feeding in the skin (0.06 inch or 0.16 mm deep) or small holes near the stem end of the fruit.
- In hazelnuts, the second generation can cause nut drop by feeding on the shell of the developing nut.
Phenology:
- Two to three generations per year (in hazelnuts only two generations).
- Overwinters as third instar larvae in hibernacula in bark crevices.
- Adult emerges in mid-May in warmer regions, mid-June in cooler districts.
- Earliest emergence is May 15 (Hood River, OR), June 1 (Yakima, WA).

OBLIQUEBANDED LEAFROLLER (OBLR) Choristoneura rosaceana
Photo: forestryimages.org