Michigan spotted wing Drosophila report for July 1, 2014

Catches of spotted wing Drosophila continue into their second week, with numbers remaining low.

This is the second weekly report of the Michigan State University Extension spotted wing Drosophila (SWD) statewide monitoring effort for 2014. Our network of traps across more than 80 sites was checked during the week of June 22 and has revealed continued activity of this pest in Michigan. The catches are generally lower this past week, but with a detection in a new location. There was a total of one male and two females trapped, one fly in each of three southwest Michigan counties: Berrien, Ottawa and Kent. This is the first detection of SWD activity in Kent County at a raspberry farm.

Comparison of average trap catches by week between 2013 and 2014

The number of flies caught in each trap was generally zero or one SWD. This indicates that SWD is slowly becoming active and growers should be on alert for this pest as their susceptible fruit crops start or continue to ripen. SWD can only infest berries when they are ripening or ripe, so currently the focus of SWD monitoring and management efforts should be on ripening strawberries and early summer raspberries. Blueberry fields that are just starting to be ripe should also be carefully monitored and managed if they have SWD captures and ripe fruit.

In addition to the use of monitoring traps to detect the adult flies, a simple salt solution of 1 cup of salt per gallon of water can be used to assess fruit for larval infestation. As blueberries, cherries, and other susceptible crops ripen, growers will need to make management decisions based on fly activity and crop ripeness stage.

For more information on SWD monitoring and management strategies, and to read past reports, visit MSU‘s Spotted Wing Drosophila website.

The weekly SWD statewide monitoring report has been funded through Project GREEEN and Michigan State University Extension. This output is generated through a network of MSU Extension field staff and campus specialists. We would like to acknowledge the following team members and thank them for their weekly scouting efforts and input into this report: Rufus Isaacs, Keith Mason, Steve VanTimmeren, Larry Gut, Peter McGhee, Michael Haas, Bob Tritten, Mark Longstroth, Brad Baughman, Carlos Garcia, Karen Powers and Nikki Rothwell.

Dr. Isaacs' work is funded in part by MSU's AgBioResearch.

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