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Leafrollers

 

Leafroller damageLeafroller damage

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.