Following up from the last post, I want to surround some insect sticky traps with wire mesh. I want that mesh to be small enough to exclude bees and butterflies, but large enough to allow cucumber beetles through.
As it turns out, that’s easy to specify. Use hardware cloth with a 1/8th inch mesh.
First, that’s the right size to exclude bees. One-eighth-inch mesh hardware cloth is literally used by beekeepers to contain bees. So that’s guaranteed small enough to exclude domestic honeybees. And, by reference, bumblebees. It’s still possible that the smallest wild bees and other beneficial insects might still be able to get through that, but we’ll see.
Second, that’s a good size to allow cucumber beetles to pass. Based on one piece of academic research, the typical cucumber beetle can pass through 1mm x 4mm mesh screen. That’s smaller in area than you would get with a 1/8th inch mesh, although the 4MM dimension is slightly larger than 1/8th inch. (Just FYI, a typical cucumber beetle is listed as 1/5th of an inch long, and about 1/10th of an inch wide.)
Finally, there aren’t a lot of other options. Unless I want to buy this from some sort of lab equipment supplier, 1/8th is the only commercially-available choice around that size anyway. Home Depot carries it in 100′ rolls. I just bought a 3′ x 3′ piece from a beekeeping supply company.
That, plus some standard yellow sticky traps, and I will be set up to try this. Alternatively, some people suggest using yellow plastic bowls filled with soapy water. Either way, the screen will exclude bees and larger insects. (Also birds — seems that garden sticky traps can be a problem for birds as well.)
The idea being to put these beneath my squash plants and cucumber plants. The sticky trap itself will sit within a close-fitting wire mesh (hardware cloth) enclosure. With any luck, the beetles will think they are blossoms and land there. And any bees that are fooled will be kept off the sticky trap by the hardware cloth.
I’ll be setting that up when the hardware cloth arrives next week, and will report back on the results.