Vinegar Fruit Fly Traps for the Raspberry Patch

This is how I spent my lunch hour today: 
I just walked right out our back door, and came back in 20 minutes later with a bowl of freshly picked red raspberries.  It was definitely one of those "this is the life" moments, and a perfect argument for why it's worth the effort and time to have a backyard garden in some form or another.

The early raspberry crop is a little late this year, but otherwise is looking great! It's always the smaller and shorter of the two crops, but a welcomed arrival nonetheless.  This week was the first week the pickings have been sizable (i.e. more than 5 or 6 ripe berries) and with a little luck, I might just squeak out a small batch of jam with the berries this weekend.  
Unfortunately, the past week also brought some bad news to gardeners with backyard berry patches in Minnesota.  Remember that little fruit fly problem I had last fall?  Well, they're back.  Earlier this week I shared this link on the Sweet Domesticity Facebook page, which breaks the news that the pesky fruit fly in question, the Spotted Wing Drosophila (SWD), managed to survive the winter. 

While I have not yet seen any sign of them in our raspberry patch, they have been confirmed elsewhere in our county, so I'm being extra diligent about picking every day and making sure there is no fruit on the ground.  But since that wasn't quite enough to control the pest last fall, I'm also adding the use of vinegar traps to my arsenal this year in hopes of salvaging more of the raspberry crop if and/or when they do show up.  
To make the traps, I followed these directions, pretty much to the letter.  I used a clear plastic beverage cup that one of my co-workers was more than happy to supply for me (thoroughly washed out, of course) and drilled the necessary holes around the top for the fruit flies to enter the trap, as well as a couple of holes right under the lip to string a piece of twine through to hang the trap in the raspberries.  
The trap is filled with about an inch of apple cider vinegar, which attracts the fruit flies.  I need to look around  this weekend and see if I can pick up the sticky traps locally (which will hang from the string inside the top of the cup to capture the fruit flies), but in the meantime a few drops of dish soap mixed into the vinegar will do the trick.  

The traps should be hung low, under the cover of the thicket, but also free from too many leaves so the fruit flies will find the holes and enter the trap.  I tied mine to some of the older canes that were growing more horizontally and could easily support the (light) weight of the trap.
Within the first several hours of placing the trap, there were already a small handful of fruit flies floating in the vinegar-soap concoction, so it is effective!  Our raspberry patch is around ten or twelve feet long, so I'll be adding two more traps over the weekend for a total of three: one on each end, and this one in the middle.  In addition to the obvious trapping and killing of as many adult fruit flies as possible, keeping an eye on these traps will also help me monitor how active the fruit flies are in the patch and if they are the SWD or not, which will in turn help me decide how early and often I need to pick the berries in order to ensure that I get more of this: 
than the fruit flies do this summer.

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