What to Watch For: How Should North Carolina Strawberry Growers Plan for Spotted Wing Drosophila?

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A few growers are starting to harvest strawberries in North Carolina, and as fruit ripen, now is the time to prepare for spotted wing drosophila management. Our recommendations for strawberries in 2014 are very similar to those we provided in 2013, with one important change.

Our recommendations for this year are:

  1. Strawberry growers should strongly consider monitoring for spotted wing drosophila.  We recommend using yeast and sugar water baits (details here).  We also discussed trapping methods and how many traps a grower should use in this post.

    It’s important to note that this trapping recommendation is only for strawberry growers. For blueberry, blackberry, and raspberry growers, traps have not appeared as useful for timing treatments in North Carolina, and preventative treatments timed to fruit ripening are likely justified.

  2. Growers should be prepared to identify spotted wing drosophila adults and larvae. Not all little brown flies are spotted wing drosophila!  See here for information on adult identification and here for information on larval identification.
  3. Growers should consider when to treat.  Last year, using the yeast and sugar water baited traps, we captured flies in our research plots before we observed infestation, but in 2012 , using apple cider vinegar baited traps, fruit infestation developed before adult flies were caught.  If treatment timing is initiated based on trap captures, be sure to use an attractive bait, not apple cider vinegar!
  4. Data from untreated control plots at the Central Crops Research Station, Clatyon, NC. Spotted wing drosophila captures in 2012 (black line, left) and 2013 (green line, right) and fruit infestation (red bars). In 2012, traps were baited with apple cider vinegar and captured flies only after infestation was present. In 2013, traps were baited with yeast and sugar water and captured flies before infestation developed. Figures: Hannah Burrack

    Data from untreated control plots at the Central Crops Research Station, Clatyon, NC. Spotted wing drosophila captures in 2012 (black line, left) and 2013 (green line, right) and fruit infestation (red bars). In 2012, traps were baited with apple cider vinegar and captured flies only after infestation was present. In 2013, traps were baited with yeast and sugar water and captured flies before infestation developed. Figures: Hannah Burrack

  5. If growers find infested fruit, they should take immediate action to remove it and prevent future damage. We have shared lots of information as to what growers should do if they find an infestation.  Insecticides recommended for use against SWD are listed in the NC Agricultural Chemicals Manual (for materials recommended for use in North Carolina) and the Southern Region Small Fruit Consortium Strawberry IPM Guide (for regional recommendations).

More information

Spotted wing drosophila monitoring recommendations for 2013NC Small Fruit & Specialty Crop IPM

More on spotted wing drosophila: How many traps should growers use?Strawberrry Growers Information Portal

Spotted wing drosophila biologySpotted Wing Drosophila Portal

Identifying larvae that may be present in strawberry fruit – Strawberrry Growers Information Portal

What should growers do if they find SWD infestations? – Strawberrry Growers Information Portal

Written By

Photo of Dr. Hannah BurrackDr. Hannah BurrackAssoc. Professor and Extension Specialist (Berry, Tobacco and Specialty Crops) (919) 513-4344 hannah_burrack@ncsu.eduEntomology and Plant Pathology - NC State University
Updated on Aug 20, 2015
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