Spotted Wing Drosophila in Texas

Snapshot:

Drosophila suzukii, Spotted Wing Drosophila (SWD), is an invasive pest that attacks several soft-bodied fruit, such as cherries, blackberries, blueberries, raspberries, strawberries and grapes.  Similar in size to the common fruit fly, except the females have a serrated ovipositor (organ used for depositing eggs), allowing them to lay eggs in fruit just before harvest.  As a result, the fruit can be unfit for fresh markets by the time they are harvested, resulting in crop loss.  If you would like to send samples to confirm SWD identification, please use the spotted wing drosophila submission form.

Hosts

Major hosts:
Credits: UMass Amherst

Crop host:

  • Apple
  • Asian Pear
  • Asian Plum
  • Blackberries
  • Blueberries
  • Boysenberries
  • Cherries
  • Cold Hardy Kiwis
  • Elderberries
  • Grapes
  • Italian Plums
  • Mulberries
  • Nectarines
  • Peaches
  • Persimmons
  • Plumcots
  • Raspberries
  • Strawberries
  • Tomatoes

Wild host:

  • American Pokeweed
  • Autumn Olive
  • Beach Plum
  • Climbing Nightshade
  • Crabapple
  • Fox Grape
  • Japanese Yew
  • Kousa Dogwood
  • Pocilainberry
  • Wild Rose

Details:

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The male spotted wing drosophila can be distinguished from other Drosophila species by the spot on the tip of the first wing vein.

Spotted Wing Drosophila (SWD), Drosophila suzukii, is an invasive pest that was first seen in California in 2008.  Unlike other vinegar flies that typically only lay eggs in fruit that is already rotting/damaged, SWD females have a serrated ovipositor, giving them the ability to lay eggs in fruit before it is ready to harvest.  As a result, fruit can have one or several SWD larvae in the fruit when it goes to market.  If left unmanaged, SWD can result in 80% or more crop loss, depending on the crop and location.  Substantial crop loss due to SWD is yet to be reported in Texas, so growers should be aware of the pest and signs of SWD damage, but do not currently need to develop control strategies.

Males can be distinguished by a spot on the tip of the first wing vein, which can be seen with a trained naked eye.  Identifying a female, on the other hand, requires the use of a microscope to see the ‘teeth’ or serrations on the ovipositor.  The larvae can be seen in the fruit with the naked eye by opening the fruit.  Look for very small maggots, no longer than 1/8 inch.  Infested fruit will tend to be softer and can be more susceptible to fungal pathogens as secondary infestations.

Very simple home-made SWD traps can be made, using apple cider vinegar as the bait.  Samples can be submitted for identification using the Spotted Wing Drosophila Submission Form.  Although SWD has been detected in Texas, no management or preventative measures are currently being suggested for growers in Texas, since there have been no reports of damage or crop loss.

Additional Resources:

Six-Legged Aggie | Presentation | Sample Submission Form

AgriLife Today | Spotted Wing Drosophila poses risk to soft-bodied fruits

Insects in the City | A berry bad pest

Michigan State University | Spotted Wing Drosophila

University of California IPM Online | Spotted Wing Drosophila

Oregon State University | Spotted Wing Drosophila

 

Creating a Spotted Wing Drosophila monitoring trap

If you plan on submitting a sample, please also submit a sample submission form.

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