Leafroller caterpillars cause damage to commercial and backyard fruit trees by feeding on both foliage and fruit. They are so named because they tie (or roll) leaves together for protection. The most common species in Utah is the obliquebanded leafroller.
The caterpillar is greenish-yellow with a brown to black head capsule. When they are exposed from within rolled leaves, they will wriggle and drop on a silken thread. Moths are around ¾ to 1 inch-long with wavy tan and brown bands on the wings.
The obliquebanded leafroller spends the winter as a larva (caterpillar) protected within bark crevices. Larvae emerge to resume feeding at bud break. They feed on expanding leaves and flowers, and complete their development by late May to early June. They pupate within a silken cocoon inside folded leaves, and emerge as adult moths June through July. Females lay egg clusters on leaves to start the first summer generation that can be the most damaging to fruit. There is then one more generation of moths that lays the eggs that will become the overwintering larvae.
- Holes in leaves in sporadic locations of the orchard or tree
- Rolled leaves
- Scarring on fruit from early feeding
- Holes or tunnels on fruit skin and flesh
Monitor for leafrollers by checking terminal shoots for rolled leaves or holes in leaves starting in mid-May. Manually kill larvae or cut out infested shoots. A pheromone trap for obliquebanded leafroller can help to determine presence and population size.
Leafrollers often do not cause enough damage in most orchards or backyard trees to warrant treatment. In some cases, obliquebanded leafrollers may be causing enough damage that requires an application. The timing options are in May to target overwintering larvae, or in late June for the first summer generation of larvae.
Residential examples include: spinosad, Bt, or pyrethrins
Commercial examples include: Altacor, Exirel, Delegate, Success or Entrust, Dipel, Javelin, Intrepid, carbaryl, or malathion