First you notice one or two metallic-green-and-copper beetles here and there. And then they’re everywhere, hundreds of munch-tanks devouring the petals of your prized rosebush or the green leaves of your peach tree. But before you reach for the industrial-grade bug killer, consider these safer options.
When I first discovered beetles in my grape arbor last month, there must have been at least 300 of them. Within a few days, I had reduced their population to about 25, plus a few more scattered about the yard. If you too have a concentrated infestation and a few minutes to spare each morning and evening, then doing as I did should guarantee you similar success.
A caveat: You can’t get them all. But at least there’s only one generation to worry about: Eggs laid in the ground in late summer won’t emerge as adults until next year. Grubs could be devouring your lawn in the interim, but that’s a separate concern.
The best way to deal with Japanese beetles in the short term is to gather them by hand. Granted, for those of us over the age of 8, handling insects can be a bit unnerving (to find out how you’ll fare, put a few beetles in your hand and let them try to push their way down between your fingers). The good news is that they don’t bite, and you rarely have to actually touch them. You can even use a hand-held vacuum cleaner, but that sort of spoils the fun. Think of stalking these space invaders as a neo-ninja game and it won’t seem as tedious. If the thrill of the hunt pales after a few days, take garden guru Walter Reeves’ advice and find a child to do it: “At a nickel per bug, a trip to the ice-cream store can soon be financed!”
The problem with commercial beetle traps is that while they can trap thousands of beetles a day, they always attract more beetles to your yard than they catch. The only effective way to use such traps, then, is to place them in someone else’s yard, which your neighbors might not be thrilled about.
It’s possible to make your own trap — perhaps a weaker one with a shorter range. Directions for a simple one can be found at www.ghorganics.com/JapaneseBeetle.html. A more complicated one is at http://home1.gte.net/aai/Trap.html.
There are also a number of “trap crops” — plants that Japanese beetles love. You just simply pick the beetles off the trap plant. But once again, you may attract more beetles than you catch. Whenever possible, then, it’s best to avoid or remove plants the beetles like. These include smartweed, Virginia creeper, wild rose and wild grape. You can find a list of others online (or just find out the hard way).
But some plants both attract and poison Japanese beetles. These include four o’clocks, larkspur, white geranium, red or dwarf buckeye and castor bean. Assuming these trap crops don’t also attract more beetles than they kill, you might consider planting them for next year. Keep in mind, however, that they’re poisonous to children and pets as well.
There are other methods: attracting birds, many of which love to eat Japanese beetles; introducing parasitic insects and diseases; and simply covering smaller plants with netting. These approaches were either too involved or just not feasible for my needs. I did try the biodynamic, that’ll-teach-’em method of putting my catch and some water in a blender and spraying that on the plants. I certainly found it repulsive, but even with habanero oil and tobacco added, it didn’t seem to faze the beetles. Fortunately, simply gathering them every morning has proved sufficient — and not a bad way to get out of the house and keep tabs on my garden as well.
The cardinal principle of beetle hunting is that the early gardener gets the bug. In the morning, Japanese beetles are either too cold or too wet to fly.
The easiest thing to do — especially if the beetles are too high up or too numerous to pick by hand — is to get out early, spread a tarp beneath the infested plant, and jostle its branches. When Japanese beetles sense danger, they bail out. On the ground, they’re usually very hard to see. Your mission, then, should you choose to accept it, is to intercept them in between. With a tarp under the plant, the job is easy. You just “shake and rake,” gathering up the pickings like mulberries (only crunchier).
With bushier plants, the tarp method doesn’t work as well. You may still be successful by holding a container under them (or just your cupped palm). Beetles that have burrowed into the center of rose or other blooms may need to be dug out.
Always look carefully before you reach for a bug. There are bound to be more, maybe even on the underside of the same leaf. If you haven’t already noticed, these beetles are awfully “social.” They can smell one another’s parfum sexuel hundreds of yards away, and they don’t hesitate to join the party. That’s great for us: It makes them easier to find, and the more you get rid of, the less attractive the spot becomes to other fun-seeking beetles. Your work has a cumulative effect.
If it’s midday and there’s no chance of getting a tarp under them soon, you can at least shake the bush or tree and have the bugs fly off — hopefully landing somewhere else. But keep in mind that this can spread them to other plants in your yard. You’ll notice that beetles start from the top of a plant and work their way down. They’re also attracted to already-compromised plants, so removing damaged leaves can help.
What do you do with them when you catch them? Some people get satisfaction from squishing them. After your 10th or so squished beetle, however, practicality tends to overtake vindictiveness, and most folks prefer to simply drop them into a container with a little soapy water at the bottom (Japanese beetles aren’t good swimmers).
For an interesting (albeit gruesome) variation, try placing your beetles in an open container without water. You’ll find that the more you add, the more likely they are to stick around. They clump together until they’re one writhing mass, and it’s not clear whether they’re climbing all over one another to escape or to mate. I suspect that excitement — whether sex- or fear-induced — releases a certain pheromone. Either way, it looks exactly like a Hieronymus Bosch depiction of hell; surely there is something we can learn from this.
When I’m done gathering I put the frantic throng in the freezer, and within a couple of minutes they’re immobile. Supposedly it’s one of the more pleasant ways to die.
So that’s the “crouching tiger, hidden beetle” method of Japanese-beetle management. Remember to look at it as fun (at least on your end). Isn’t that a good approach to life in general?
[Author, editor and educator Alan Muskat can be reached at http://www.alanmuskat.com]