As much as I held out hope that the Japanese beetle population had been wiped out by an unusually fortuitous twist of fate, my watch for the invasive insect ended today with the discovery of several beetles on my raspberry bushes.
If you have rose bushes, grapes, hollyhock, linden trees, pin oak, willows or raspberries, be on the lookout, as these plants are among the favorites of Japanese beetles. But really, they’re not that picky.
The beetles, easily identified by their copper-colored wings and metallic-green heads, are known to devour at least 300 different plants, turning the foliage into lace.
Iowa State University Extension notes that Japanese beetles also are becoming a common corn and soybean pest. ISU produced a map last year that showed the beetle had made its way into nearly 60 of Iowa’s 99 counties, after first being recorded in the state in 1994.
In the past, I was a bit squeamish about smashing the bugs with my bare hands, but no longer, especially after witnessing the destruction these foreign invaders wreak.
I’ll still use my favorite method on larger numbers: knocking them into a bucket of soapy water. This tends to work better in the late afternoon, when the beetles have less of a tendency to fly away and escape.
I avoid insecticides and haven’t tried the pheromone traps that some gardeners use to lure large numbers of Japanese beetles to their deaths.
Organic methods of control include using milky spore in the soil, which treats beetles in the grub stage, and chickens, which devour both the Japanese beetle grubs and those in the adult stage.
A friend passed along this method, which I intend to try this year. Last year, she had some success sprinkling self-rising flour on her plants. She noted that the foliage showed some effect from the treatment, “but not as much as having everything chewed off.”
Congratulations on the first siting. I have one add to your post.
While the pheromone traps can successfully attract Popillia japonica, not all fall into the trap, and many feast on nearby delicacies. A neighbor placed several traps on the border of their large property a few years ago, which happened to be next to my small orchard. Yikes! The leaves on the apple trees were more lace than chlorophyll. Too, there is the issue of what to do with the carcasses of tens of thousands of deceased insects. A friend tried burning them, but the exoskeleton survived the intended pyre. They collected dozens and dozens of bags full of the metallic pests from only a few traps. Advice on what to do with the dead Japanese Beetles would be appreciated.
Thanks for posting this. Hope they stay away from here a while longer.
I have a similar problem with the soapy water full of dead beetles, which I usually dump onto the ground and they eventually decompose. I wonder if the bagged beetles can be composted??
They are at this very minute happily chewing on the vines outside my office window. Makes a rather grisly site, as many of them as there are.
Oh no! Already out in full force!
I’m in Central Illinois and I can tell you for a fact that they are out in full force. At my place it happened within 3 days when I spotted the first couple beetles. Today, my rhubarb, a very large yellow apple tree, a linden tree and my asparagus patch are absolutely covered. They were swarming right outside my garage door at noon today. There are so, so many here right now that I have written off the rhubarb patch so I applied Sevien earlier which seemed to have not much of an affect on them. About an hour after application the leaves of all plants were covered with live, breeding beetles. I just went out 30 minutes ago and sprinkled self rising flour on the rhubarb and the asparagus and sat back and watched. The beetles flying in are not landing and if they do, its short-lived. They leave. The others are dropping off. Too bad I cant have a crop duster dump a load of flour on the entire property….
Thank you for your note, Debbi. That’s a great tip! I’ll have to give that method a try.