Post #G21-029: Bee-proof cucumber beetle traps, Part 2

Posted on June 3, 2021

See Post #G21-028 for the background.  Briefly, I’m trying to get rid of cucumber beetles in my garden.  The last time I tried sticky traps for this I caught many beneficial insects along with cucumber beetles.  At which point, I called that a failure and tossed out the sticky traps.

Today’s question is, can I set up a sticky trap that will catch cucumber beetles and not catch beneficial insects?

In this post I show the simple construction of a “bee-proof” sticky trap.  It’s a sticky trap enclosed in a fine-mesh (1/8″ square) hardware cloth cage.

I have no idea yet whether or not these will work.  This post documents the construction of the bee-proof sticky traps.  Next post will give the results, if any.

This build starts with a beekeeping supply house.

I ordered 3 feet of 36″ wide 1/8″ square mesh hardware cloth from Blyhthewood Bee Company.  (I ordered from them despite the name, which I thought was chosen to be cute and olde-tyme sounding, but turns out simply to be the name of the town where they’re located.)

Beekeepers routinely use this type of hardware cloth because honeybees can’t get through it.  I thought that was a good start, given what I’m trying to do.  Blyhthewood Bee Company was one of a handful of beekeeping supply companies selling 1/8″ mesh hardware cloth for a few dollars a running foot.  With shipping, I paid about $22 for three running feet (9 square feet) of this.  That looks like it will be enough for maybe 40 bee-proof traps, far more than I need.  Blyhthewood Bee Company shipped my  measly three feet of hardware cloth rolled, not folded, which I greatly appreciate, because that makes the next step much easier.

As you can see, this cloth has a fine-but-not-too-fine mesh.  That’s what makes it a specialty item.  At eight openings per inch, it’s coarser than window screen (typically 16 openings per inch), but much finer than the hardware cloth you can routinely buy at the hardware store (typically 2 to 4 openings per inch).  Some insects can pass through it, some can’t.   It will, for example, keep bees in a beehive, but allow bee mites to fall through onto a sticky trap below a beehive.

Next up, here’s a picture of my cheap sticky traps from, and the tools needed to make the bee-proof cages for them.  I think I paid about 15 cents each for the sticky traps.  They are flimsy, but seem to work just fine, with the protective paper peeling away easily to yield a very sticky surface.

Those are the only two tools needed.  At the right is a set of tin snips, on the left is a set of needlenose pliers.  These are the right tools, but neither one is critical.  You can cut this hardware cloth with scissors (if you don’t mind dulling the scissors), or even just slice it with a utility knife.  You can bend it with any set of pliers you have handy.

Next, cut a strip off the roll of hardware cloth that is about twice as wide as the sticky trap is long.

Fold the strip in half lengthwise, and start cutting off pieces that are maybe 1.5″ longer than the height of the sticky part of the sticky trap.  This shows you what you are aiming for — the hardware cloth will form a little cage around the sticky trap.  You just need enough excess to allow for a little space between the wire and the trap, and to allow for the ends of the wires to be folded over.

Now make the hardware cloth pieces into open-ended envelopes.   Use the pliers to turn over and crimp the top and the side, leaving the bottom open.

You end up with a little bee-proof protective cage.  All told, each unit costs about $0.70 ($0.55 for the screen, $0.15 for the trap), and once you get going, takes about a minute to make.

Where to put them?  Cucumber beetles like to chow down on squash pollen, and are typically found in the male squash flowers every morning.  I’m putting the majority of these in with the squash, and putting a few in with my cucumbers.  Here’s a couple of shots of these in among the summer squash.

The only remaining questions are a) will this fool the cucumber beetles, b) will they be willing and able to get through the mesh, and c) will any beneficial insects get through the mesh?  The silver mesh does seem to dull the color quite a bit.  But the nice thing is, these are one-way traps.  Each cucumber beetle only needs to mistake it for a squash flower once.

This is a specialized trap, in the sense that it won’t work for just any old pest.  It relies on the fact that cucumber beetles are tiny, while bees are not.  But the same concept should work for other tiny flying pests such as aphids, white flies, and the like.  This ought to be a way to catch any type of small flying pest, while keeping bees, butterflies, and birds away from your sticky trap.

I’ll come back to show the results in a couple of days.