Spotted wing drosophila, invasive fruit fly

Date: 

2012 to 2014

Summary: 

Spotted wing drosophila (SWD) Drosophila suzukii, originally from Asia, is an invasive fruit fly that became established in NY and surrounding states in autumn of 2011. Unlike other fruit flies that typically only infest overripe and rotten fruit, female SWD oviposit in ripe fruit, thereby making them unmarketable. Economic loss projections for NY fruit are estimated at $5M. Soft-skinned fruits are at greatest risk. We monitored adult SWD and larval infestations in berry and stone fruit crops, as well as potential wild hosts, to determine the most at-risk crops, timing of infestation, and the role of wild hosts. Populations explode in mid-August, forcing many berry growers to close fields and abandon the crop. We provided leadership for the consortium, Northeast Spotted Wing Drosophila (SWD) IPM Working Group. The Working Group develops and ranks research, education, regulatory, and extension priorities for dealing with this invasive fruit fly.

Issue: 

The Highbush Blueberry Council and surveyed fruit growers say the loss of product and jobs from spotted wing Drosophila (SWD) may exceed one billion dollars and could go up if effective means for managing the invasive insect are not developed and adopted by growers. The invasive fruit fly, SWD, caused severe damage to fruit crops in 2012, catching farmers off-guard and devastating crop yields. Female SWD oviposit in ripe fruit, making them unmarketable. Soft-skinned fruits that ripen in late summer and autumn are at high risk; especially fall raspberries, blackberries, and blueberries. Cherries, peaches, plums, day-neutral strawberries and grapes support SWD infestation, though damage is not as severe. Approximately 30% of the blueberry crop and 80% of the fall raspberry crop can be lost. Economic loss projections for NY fruit could exceed $7M and many growers are not planting susceptible fruit or are abandoning plantings. Control relies on routine and repeated insecticide applications.

Response: 

We monitor adult SWD and larval infestations in fruit crops and potential wild hosts through the season to determine crops at most risk, timing of infestation, and the role of wild hosts. Over the course of the growing season and into the fall, SWD was found everywhere we deployed traps. By mid-August severe infestations are found and being reported from across NY with infestation development being exponential. Populations explode in August, forcing many berry growers to close their fields and abandon the crop. A SWD online distribution map is being updated routinely and new finding reports are reported on the Spotted Wing Drosophila blog, blogs.cornell.edu/swd1/. We also post findings on the Cornell Fruit Resources spotted wing Drosophila web page, www.fruit.cornell.edu/spottedwing/, to keep people informed of the outbreak of this introduced, invasive species.

Wild hosts including dogwood, bush honeysuckle, pokeweed and buckthorn supported large populations of SWD. Research in NY was supported by lobbying efforts of the NY State Berry Growers Association and improvements in trap and lure design, cultural management practices, netting exclusion, and chemical control are being implemented as rapidly as is feasible to address the threat of SWD to the fruit industry. Dale Ila Riggs, President of the NY State Berry Growers Association, stated that this problem desperately requires financial support for research and she has been tirelessly communicating our findings to key NY State Legislators, Departments and Programs to garner support for needed SWD research.

We know from reports and a survey of berry growers that many abandoned these crops rather than continually spray insecticides, removed the crops from their farm, or decided against planting additional acreage of these crops. It is imperative that we develop IPM practices to combat SWD. Results from our work will benefit all small fruit and stone fruit growers in NY, including 2,000 acres of strawberries, 500 acres of raspberries, 900 acres of blueberries, and over 3,800 acres of peaches and sweet cherries.

We provided leadership for The Northeast Spotted Wing Drosophila (SWD) IPM Working Group, sponsored by the Northeastern Integrated Pest Management Center, which met in 2012 and 2013. The 50-member working group comprises research scientists, extension educators, industry consultants, and growers from ten states in the northeastern U.S. and from three Canadian provinces. Dennis Doyle, representing the U.S. Highbush Blueberry Council, was emphatic in his plea to researchers to “find a solution to this problem.” Mr. Doyle stated that in his more than 30 years in the blueberry business this is the worst problem he has seen for growers. The Working Group develops and ranks research, education, regulatory, and extension priorities for dealing with this invasive fruit fly—published at www.northeastipm.org/working-groups/spotted-wing-drosophila/priorities/. The Northeast IPM Spotted Wing Drosophila Working Group has taken a first step toward finding sustainable and effective IPM strategies against spotted wing drosophila—a step that is critical for the future of the berry industry.

Impact: 

The greatest impact of the work to date has been to identify at-risk crops and wild hosts for SWD in NY and alerting Senator Schumer’s office, the NY Berry Growers Association, and Cornell Cooperative Extension Educators about the gravity of the problem and its potential economic impact of $5M. This invasive insect could bring back an era of repeated insecticide applications based on the calendar rather than on IPM. The priorities developed by the Northeast SWD IPM Working Group provide a solid foundation for funding support.

Cornell Cooperative Extension Educators in three regional fruit programs and nine county associations have joined together to address this invasive threat to fruit crops in NY, engaging in monitoring with improved traps to provide warning of SWD arrival and the need to treat. Information resources on the Internet at Cornell Fruit Resources and the Spotted Wing Drosophila blog have served to alert growers about SWD and improved IPM has resulted.

Submitted by: 

International focus: 

  • Georgia
  • Canada
  • United States of America

United States focus: 

  • Washington
  • New Hampshire
  • Florida
  • Oregon
  • Ohio
  • Pennsylvania
  • Delaware
  • Georgia
  • Rhode Island
  • South Carolina
  • Massachusetts
  • California
  • Wisconsin
  • New Jersey
  • West Virginia
  • Vermont
  • Maryland
  • Tennessee
  • Maine
  • Alabama
  • New York
  • Michigan
  • North Carolina
  • Connecticut
  • Kentucky
  • Virginia

New York State focus: 

  • Delaware