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Spotted Wing Drosophila


spotted wingspotted wing pattern

Hosts:  all fruits, especially soft fruits

  Overwinter as adults and pupae; adults lay eggs inside fruit and maggots feed on pulp.  SWD adults have been trapped in Utah orchards, but no fruit injury has been detected.

  Sunken fruit; holes in fruit.

  SWD has been found in northern Utah in low numbers, and in north-central Idaho in high numbers.  Monitoring should be done using traps containing a cider vinegar or sugar-yeast bait.  See the USU Spotted Wing Drosophila factsheet for more detailed information on monitoring techniques.

Treatment Threshold:
  None determined yet.

Degree Day Model:

  • Lower threshold:  50°F
  • Upper threshold:  88°F
  • Start date:  Jan 1
  • Peak adult emergence:  755 DD after Jan 1

Management Considerations:
  Monitoring will help to determine if this pest has been introduced to your area.