Attract and Kill- SWD

There has been promising research to reduce the population and egg laying of spotted wing drosophila using attract and kill stations, they are hung in fruit rows and sprayed weekly with a mixture or raspberry concentrate, apple cider vinegar, yeast and a pesticide for adults to feed on.

It is important that the attractant stations are round shaped and red colored to visually attract SWD. The most current construction Mr. Jentsch is using is a mesh disc which is coated in super absorbent polymers and gelatin (pictured in the video below), but just water polymer crystals were used initially. There are no products available for sale that I know of, so it is strictly DIY. Whatever is used it should wet rapidly to absorb morning dew and weekly sprays of the solution and hold plenty of liquid to increase the amount of time it stays moist.

The recommended pesticide is borax, which seems wise to reduce the risk of resistance of other sprays. The combination of sprays and attract and kill stations provides better protection than either alone during high pressure.

My own thoughts are that these could be useful in areas where alternate hosts drop their fruit to reduce the population. And that the Fruit Fast brand raspberry concentrate is too expensive for me, will attempt to make a homemade attractant from mulberries or spoiled berries instead.

Here is some more info:

I requested the full text of the most recent article on the subject, but have not received a response yet:
Developing attract and kill strategies to manage spotted wing drosophila, Drosophila suzukii Matsumara, in organic raspberry and blueberry


I still question if bait stations is the best way? Most say never to use the Japanese beetle traps. I have gallons and gallons of frozen raspberries, making a concentrate is not a problem.
One farmer has had good luck attracting hummingbirds which love to feed on fruit flies. I’m going to add a few humming bird feeders to the garden.

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My understanding is Japanese beetle traps can be problematic because the beetles themselves are mostly attracted to their own pheromones (or the pheromones used as an attractant in the traps). Because Japanese beetles feed on so many different types of foliage and can be so ubiquitous to an area, using a pheromone attractant near one’s planting, can draw in and congregate the beetles to the planting.

I think this is somewhat unique to Japanese beetles though. Pheromone traps for Codling moth and OFM don’t tend to congregate the pests because if you have an orchard, almost all of these pests in the area are already going to be at the orchard anyway.

I think if one has a blackberry or raspberry planting, the same would apply. SWD would view the planting as a buffet, or a sort of oasis in the middle of a food desert.

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Makes a lot of sense Olpea,

Luckily their are ways to avoid SWD with blackberries or raspberries. Many blackberries are early fruiting. Natchez, Boysenberry, wyeberry,and tayberry is a little later but before SWD.
Most summer fruiting raspberries, or fall being pruned for summer crops miss the window. Here at least.

I’m hoping the humming bird thing works. At my cottage we watch them all the time. It sounds too good to be very effective though! Nothing ever seems that easy to do!
I’m just thinking though since they need to eat several dozen insects a day, they will have insects, water and energy all in my yard. A blurb from a birding site.

Insects: Small insects, larvae, insect eggs and spiders are critical food sources for hummingbirds. Insects provide the fat, protein and salts the birds cannot derive from nectar, and these are crucial nutritional components, especially for rapidly growing hatchlings. Hummingbirds may hunt insects in several ways, including gleaning or picking them from bark, flowers or leaves, hawking them in midair or plucking them from spider webs or sticky sap. To get the required amount of protein for a healthy diet, an adult hummingbird must eat several dozen insects each day. They will eat many more, however, if they need to regurgitate this nutritious food to hungry hatchlings, or if they are in the midst of a long migration.

Here is another blurb

To settle the question of what, exactly, hummingbirds eat, early ornithologists shot a number of them—a perfectly legal activity in those days—in order to examine the contents of their stomachs. Upon dissection, they discovered the remains of such prey as flies, gnats, wasps, aphids, beetles, leafhoppers, and spiders, often completely packing the abdominal cavity. Zoologist and museum director Frederic A. Lucas found that the stomach of one hummingbird “contained remains of not less then 50 individuals, probably more."

I’m putting up at least 3 feeders all around my garden. Even if it doesn’t work completely I want these birds in my garden and I’m going to give them reasons to always come back. I will make sure those feeders are always full.

Here’s the articles that started me on this



Thanks for the link to the Charlie O’Dell article on SWD. Very interesting information.

He is a very well known and respected researcher in my part of the country.


Would you (or anyone else) have any ideas on what type of “mesh disk” Jentsch is using and what is meant by “super absorbent polymers” ?

I’d like to try this method, but I don’t know where to get these materials. I’m thinking the mesh disk are those scrubbing pads? I have no idea where to get super absorbent polymers.

If anyone thinks they might know of an online source for these materials, please let me know.

I think the humming bird idea is a good one, but I don’t think it would work for me. I’m afraid if the humming birds didn’t work good enough for me, I’d have to spray (which might be bad for the birds) and the sprayer would probably blows any nests they made out of the trees.

I think the polymer is sodium polyacrylate. It is available in various sizes, the smaller the better so it sticks well with the gelatin. The mesh is partly visible in one of the slides from the above .pdf, couldn’t find any specifics. Look at all of the swd it attracted though!

I was thinking of just bundling up some of the polymers in pieces of old row cover, they would be harder to rewet than a flat disc though.

Thanks Hoosier,

I’m still having some trouble visualizing exactly how this comes together. There are so few details given by Jentsch.

Please let me know what you think of this “recipe”.

-Take a red fiber mesh cloth and cut it in disks (although it looks like Jentsch is using white mesh cloth).
-Mix sodium polyacrylate and unflavored gelatin (in what ratio, I’ve no idea) and shake the disks in the powder, to embed the powders inside the mesh disk.
-Then wet the disk to saturate the gelatin and polyacrylate within the mesh disk.
-Mix a 75% rasp. concentrate, 25% apple vinegar, 1% borax in a spray bottle as poison bait.
-Spray the disk(s) with the poison bait and hang them in the planting.
-Renew the poison bait on the disks every 4-7 days by respraying with the spray bottle.

Does any of that sound wrong to you, or do you have any better ideas?

Maybe the Sodium polyacrylate and gelatin could be mixed to a thick syrup and the mesh dipped into it. Brady


I was hoping that there would be more technical information in the paper I requested, it has been 2 weeks though…

I think Brady has the right idea of mixing it up and dipping the discs, the gelatin needs some heat to melt. I am a little confused about using gelatin actually because it would remelt on a very hot day and might slide off.

I’m not sure why this method is so special? I myself would try more conventional traps. I can paint anything red, and use the attractant in any bait station. Luckily I never spray my brambles with pesticides most years, I can use the birds no problem. I also have large suitable trees nearby for nests (not fruit trees).
I also can see if you have a yellowjacket problem, those things overwhelming the discs, or any station. I plan to bait them next year. they were super bad this year.

The mix is 75% vinegar so yellowjackets are probably not going to prefer the discs over fruit. That is something to think about with hummingbird feeders though.

There will be low impact on other bugs since the discs are the only thing that get sprayed. Spiders seem like ideal predators for fruit flies.

There are red/round traps being developed but they will cost much more and take more time to manage. The discs are modeled for commercial growers who will need hundreds or thousands.

Making a trap more attractive than fruit is a hard thing to do since the smell only leaks out the entrances, the discs are a better simulation of fruit.

I didn’t think of gelatin melting on a hot day. It must not be too bad though because apparently it works for Jentsch (although perhaps it doesn’t get quite as hot in NY as it does in other places).

Any ideas on the mixture ratio of the gelatin and polyacrylate?

Thanks for clarifying that!

The article indicated color and shape are pretty important. Plus it’s important the traps be moist and hung throughout the canopy. (apparently the gelatin and absorbing polymer re-wet themselves with dew). I’m thinking one can directly hang these traps on the canes with twist ties (sort of like fake fruit). If yellow jackets decide to visit these traps and, go to their doom from the poison. :joy:

I noticed the polyacrylate is sort of costly on the Internet, even for relatively small quantities. Thinking out of the box a little, I wonder if one could buy disposable diapers and mine the absorbing polymer out of them?

I thought they used the same stuff used in Soil Moist?
I would think homemade bait traps can be set up not to dry out too. Using a pool of liquid, easy enough to see if it’s dry or not. Throw some soil moist in there…

I just remembered Nourse sent a sample of viterra agri-gel to dip the strawberry roots in last year that I didn’t use… It is potassium propenoate-propenamide copolymers. So that is what I will experiment with, a half ounce is supposed to make 1-2 gallons of slurry so it seems cheap enough. I am not sure about the gelatin, most of the liquid will be absorbed by the polymers so just the extra bit that makes it a fluid needs to be solidified. It could be added gradually to the heated slurry until cooled samples are solid enough to stick well.

For the Raspberry part,I may get some fresh or frozen berries and run them through a food strainer. Brady

Thanks Hoosier,

Since you mentioned that, I also remembered Nourse sending that stuff. Here is a link to get a little larger quantity from Nourse Accessory Agrigel

I also found what appears to be a pound of it on ebay pretty cheap with free shipping.

I’m thinking you are right, the gelatin would just be enough to make the absorbent polymer stick together and stick to the mesh.

@Olpea, the absorbent material in diapers is typically poly acrylic acid.

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Looking it up, its already in the sodium polyacrylate form so diapers would possibly be a cheap source of the absorbent polymer to try.

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It might depend on how much is in each diaper, bars of gold are cheaper than diapers!

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