Some years are worse than others for yellow jackets. I've read and been told that dry years are worse, and that seems true. Supposedly they are beneficial insects because they prey on pests, but they aren't too beneficial when they sting me and my family, our livestock, and feast on my honeybees. This is especially bad in the fall, when I can see them overwhelming any defense the bees mount to steal their winter stores of honey and pollen, and carry away their larval young and developed adults. They will even kill the queen. The trick is to act against the yellow jackets and not the bees. This is what works for me.
This year the yellow jackets were abundant and aggressive, invading every corner and nook of our farm. My first course of action was to regularly make rounds and kill nests. I never expected to wipe out the population, but it was an attempt to curb their population close to areas we and our animals frequent. I could still see them entering and leaving my bee colonies, so I needed to do something more.
In the winter I use entrance reducers that have holes just large enough for a single bee to slip in and out of, but yellow jackets are slender enough to use those holes. After watching them rob my bees blind and kill them, I had enough and wanted to kill the yellow jackets off. The problem is to kill them without killing the bees now or poisoning their hives.
I have used the yellow jacket traps that you purchase from the store with attractant in them. But, I have found that they love to raid food, including cat food. Also, the trap catches quite a few, but I wanted something I could do without purchasing a trap. Also, something I could use in large quantities without reducing their effectiveness. The yellow traps with lures aren't supposed to be used too densely or it decreases their effectiveness.
The solution is to make homemade traps. For this, use a 2-liter soda bottle. Cut the top portion off at about the height of the upper edge of the label. You will invert the spout and drop it into the base. This will funnel curious and hungry yellow jackets into the lower portion but make it difficult for them to escape once they are inside. The top does not need to be taped or attached to the bottom, which makes for easier cleanup.
Baiting yellow jackets and not bees isn't difficult. Bees search for nectar and fresh fruit smells. Yellow jackets like this, too, but prefer protein. They will eat lunch meat, chicken, fish, and spoiled fruit, which is very evident when we've had overripe cherries drop on the ground and the yellow jackets arrive in great numbers for the harvest. To lure the yellow jackets into the bottle, hang a little meat on a string. The string can be draped over the side of the bottle without to top dropped in. You can also glue the bottle lid to the inside as a little container. You don't need a lot of meat as they seem to have a very good sense of smell.
Another part of the bait is also the fatal trap. Fill the bottom of the bottle with about two inches of sugary water (does not need to be very thick - can be barely sugary) or sugary soda (not diet). To make it unattractive to bees, add some cider vinegar so it smells spoiled to them. When the yellow jackets enter the bottle looking for meat or something sweet, they will fly around inside for a while and eventually get tired. They will then land on the surface of the water or soda to rest. To weaken the surface tension of the water so they fall through, add just a little liquid soap to the water. When they land, they will fall in and become trapped in the liquid.
On heavy yellow jacket activity days, they will fill the bottom of the bottle in a matter of a few hours. It may be even less time early in the fall after a long dry summer. If you need to empty the bottles frequently, I suppose you can pour them on the ground, but I hate the thought of releasing any alive. I have a little bucket with water and I add them to it. The water keeps them submerged to be sure they drown. The next morning after they've had all night to be completely dead, I dump them in an abandoned corner somewhere or pour them on the compost pile.
It is gross and somehow a little satisfying to see a pile of dead yellow jackets. I like being able to trap those feeding on my hives without using any poison or traps that my hurt or kill my bees or taint their honey or food supply. I also sometimes catch other predatory insects such as other wasps or hornets.
Another note about these traps is that they are subject to blowing over. We have a lot of wind where we live, especially in the fall. I take a cafeteria-like tray or cinderblock or old plate I don't use inside and epoxy the bottle to the tray, block, or plate. I can add weights, if needed. This keeps it from blowing away, but does not impair their effectiveness.
If you have rain that comes through, check the traps as they will fill with water. There needs to be space under the spout of the bottle so that the yellow jackets can enter the traps.
Wife to Brandon, mother to Tess and Liam, farmer, entrepreneur, cook & baker, nurse, and accountant who loves to try new things, travel, and work toward greater self-reliance.