Hosts: apple, hawthorn, plum
Biology: Adults lay eggs in host fruits in mid to late summer; maggots drop to pupate in soil.
Symptoms/Damage: Knobby fruit with cone-shaped pits; egg-laying scars; narrow brown tunnels in flesh.
Monitoring: In Utah, this fly has been trapped in backyard apple and plum trees, and maggots have been found in plums but not in apples. In Colorado, it is found in apples from Colorado Springs to Loveland, CO. Apple maggot has not been trapped in commercial orchards in Colorado, Utah, or Idaho. It has been found infesting home garden plums in Utah. Its native host is river hawthorn.
To monitor, hang red sticky sphere traps or Pherocon AM yellow sticky traps starting in early July at orchard borders.
Treatment Threshold: According to Cornell University, treat when 5 flies per trap are caught.
Degree Day Model:
- Lower threshold: 44°F
- Adults active at 1450 degree days after March 1
Management Considerations: This pest is regulated by a quarantine to prevent its spread.