Leafrollers
Hosts
All fruit trees
Biology
Leafrollers (obliquebanded, OBLR; fruittree) are usually minor pests in the Intermountain West. OBLR larvae can damage tart cherries just before harvest if populations are high. Depending on the species, they overwinter as pupae or eggs and emerge in spring. Only the obliquebanded leafroller has more than one generation.
Symptoms/Damage
Rolled, chewed leaves; dimpling or scarring on fruit.
Monitoring
Look for rolled leaves at shoot terminals starting in late May; monitor adult populations with pheromone traps.
Treatment Threshold
No threshold determined.
Degree Day Model
OBLR:
- Lower threshold: 43°F
- Upper threshold: 85°F
| Event | Degree Days |
|---|---|
| Hang pheromone traps in orchards | 600-700 |
| First months of 1st summer generation expected | 1025-1175 |
| Set biofix at first month | 0 (reset to zero) |
| 1st generation egg hatch | 400-920 |
| 2nd generation egg hatch | 1590-2360 |
Management Considerations
In apple and pear where OBLR injure fruit, suppress overwintering larvae in the spring (half-inch green to petal fall); insecticides applied for control of codling moth will often suppress OBLR later in the season. In tart cherry where OBLR larvae injure fruit just before harvest, select an insecticide that kills OBLR in the mid to late cherry fruit fly control program.