I remember Japanese beetles from my childhood in Maryland: colorful little insects that were fun to collect in jars while they ate plants and flowers to shreds. I really haven't had to deal with them personally since then.
Earlier this summer, though, a couple Japanese beetles were turned in to the Sedgwick County Extension Office and, not much later, a fellow Kansas garden blogger from the Manhattan area wrote about seeing them locally at a nursery. It would appear that they are knocking on our door.
So a week ago, when we visited our good friends, Flip and Shelley, in the Chicago area, I was both intrigued and somewhat horrified by the plethora of Japanese beetles in their garden. I don't remember seeing them when we've visited before.
Here, in no particular order, are my thoughts and observations as I explored the garden during our visit....
Japanese beetles are smaller than I remember. My memory paints them as about the same size as June bugs, but they are actually about half that size. The beetles are, however, just as pretty as I remember them.
Japanese beetles LOVE roses, both the blossoms (especially the blossoms) and the leaves. A single Japanese beetle can wreak havoc on a rose bloom in a very short period of time.
Based on their name, Japanese beetles would appear to be from Japan. Many roses are from that area of the world too. I wonder what keeps them under control in their native range?
There were many plants that the Japanese beetles did not appear to consider edible in Shelley's garden: clematis vines, Russian sage, Oriental lilies, Echinacea, and Joe Pye weed, for example, were all left alone. On the other hand, the Japanese beetles seemed to relish roses (as mentioned), wisteria leaves, grape vine leaves, hollyhocks, and even elm leaves.
The Japanese beetles were horny little things. Mating pairs were everywhere. No wonder they expand their range so rapidly! The photo above shows typical damage on a brand new rose shoot.
I was able to decrease the numbers of Japanese beetles in Flip & Shelley's garden a bit by using my favorite "soapy water in a jar" method of termination, but the beetles (especially when the day was warm) were excellent at evading capture, both by dropping to the ground and by flying away. Many even combined the two escape routes: they fell halfway to the ground and then opened their wings and flew away.
The beetles tended to feed in groups and must have released some sort of pheromone when disturbed, because snagging one individual would cause a mass exodus of almost all nearby beetles, even if I captured the one without jostling any nearby leaves. At best my efforts allowed a few sprays of roses to bloom long enough that we could have cut them off for display in a vase. I was also able to get a couple photos.
Despite the beetles' gorging on petals, the blooms appeared to set seed (hollyhocks) or develop hips (roses) as normal. There were grapes developing on some of the grape vines too. So it would appear that the beetles may function as pollinators - or, at any rate, don't negatively effect fertilization - when they eat the petals into oblivion.
That said, Japanese beetles cannot be said to improve the beauty of a garden. They leave stubs of petals on blossoms, skeletonize the leaves and generally just create a mess of their favorite food plants.
I sure hope they decide that central Kansas isn't welcoming territory and stay the heck away. The last thing that gardeners around here need is one more horde to attack!
