Spotted Wing Drosophila ID and Biology

Identification/Lifecycle

Spotted Wing Drosophila

  • Overwinter as adults and maybe pupae in leaf litter, duff, and rotting fruit
  • Adult flies live for up to 2 weeks
  • Females can lay 300 eggs
  • Can develop from egg to adult in as little as 8 days
  • Likely to have over 10 generations per growing season

Damage:

  • Females lay eggs in fruit
  • Larvae eat flesh, which renders it unmarketable or causes customer discontent (infested fruit ‘melts down’ in 2 days)
  • Egg laying introduces fungal pathogens, which rot fruit
  • See more examples of damage at The Univ. of Wisconsin - SWD in Wisconsin and Recognize Fruit Damage from SWD (OSU)

Crops at Risk:

This insect has a wide host range but is primarily a pest of berry crops and some stone fruits (cherry, nectarine, peach), but may also be found in high tunnel tomatoes.

Identified SWD Host Plants; Cultivated and Wild
Cultivated Host Cultivated Host Wild Host
Apple Gooseberries American Pokeweed
Asian Pear Grapes Autumn Olive
Asian Plum Mulberries Beach Plum
Blackberries Nectarines Climbing Nightshade
Blueberries Peaches Crabapple
Boysenberries Persimmons Elderberry
Cherries Plums & Plumcots Fox Grape
Cold Hardy Kiwi Raspberries Japanese Yew
Currants Strawberries Kousa Dogwood
Elderberries Tomatoes Porcilainberry
    Wild Rose

Plants in highlighted letters represent preferred hosts

Significance:

  • Unlike other fruit flies, SWD attacks sound ripening fruit
  • Once eggs laid in fruit, no longer able to control with pesticides
  • Short lifecycle and overlapping generations make spray timing difficult
  • Requires sprays near harvest time
  • Requires multiple sprays which can lead to pesticide resistance

For more resources on SWD identification see the following links:

Spotted Wing Drosophila
Spotted Wing Drosophila on fruit
Spotted Wing Drosophila life cycle