Larval infestation of strawberries.

2014-15 Rapid Ag: Population Dynamics of Spotted Wing Drosophila

November 28, 2014

Principal Leader

William Hutchison



Funding Awarded

  • 2014 Fiscal Year: $81,506 
  • 2015 Fiscal Year: $39,685

The Problem

Spotted wing Drosophila (SWD) was first found in Minnesota in 2012. There are still many questions as to how SWD will impact strawberries and other fruit in Minnesota. Research is needed to explore what can be done to stop the rapid spread of SWD and what the economic impact will be for the Minnesota soft fruit industry. 


SWD, is an emerging, invasive fruit pest in North America. Unlike most Drosophila species, SWD uses its saw-like ovipositor to penetrate the skins of ripening soft fruits such as raspberries, grapes, cherries, and strawberries. The internally-feeding fly larvae cause severe damage to infested fruit, and SWD infestation can also lead to secondary bacterial and fungal infections.

SWD was first confirmed in Minnesota in August 2012, placing an estimated 750 acres of raspberries, strawberries, grapes, and blueberries (valued at ~ $9.9 million) at risk. As of December 2012, presence of SWD has been confirmed in 29 counties, with quantitative GIS analysis of data from state-wide trapping revealing SWD “hot spots” in the central and southern portions of the state. Together, these data suggest a rapid rate of spread by SWD throughout Minnesota, despite its recent introduction here.

The presence of SWD can be viewed as a “game changer” for Minnesota soft fruit production, as these crops have historically required few insecticide treatments. Increased chemical inputs add substantial new costs to growing operations, as well as increase non-target risks to Minnesota ecosystems. There is particular concern for Minnesota’s growing number of high tunnel operations (now >5000 statewide, valued at ~ $25 million), as 2012 monitoring indicated SWD infestations within these structures. Given its high potential for rapid spread and economic impact, it is imperative that we improve our understanding of the underlying demographic processes that shape SWD geographic distributions in Minnesota; these results will form the foundation for future Integrated Pest Management (IPM) solutions.


  1. Assess overwintering potential of SWD
  2. Expand SWD trapping networks
  3. Compare early‐trapping patters in open‐field vs. high‐tunnel berry operations
Spotted-wing Drosophila adult

photo credit: Bob Koch

Spotted-wing Drosophila is an emerging, invasive fruit pest in North America.