Plotting a new way to control Japanese beetles

    There are more kinds of beetles on earth than any other kind of critter, and lately it seems all of the bad ones are in the news. We’re protecting our ash tree from the emerald ash borers, so that’s a win. We aren’t sure if the viburnum damage I’ve noticed is the beginning of an invasion by viburnum leaf beetles, but we’re watching it, so I consider that a draw. But the Japanese beetles are not only munching the roses this year but eating up everything else in sight. We have lost that battle, at least for this year.
    Japanese beetles aren’t all that common in Japan, although they wreak havoc in North American gardens. They aren’t a new pest since I can remember my mother plucking them out of her roses more than 50 years ago. The beetles haven’t been an issue along the lake until recently, so the past several summers we’ve been strolling the garden, containers of soapy water in hand, picking the iridescent insects off our plants and chucking them in the water where they drown. I’m not a fan of killing things, but sometime you have to be ruthless.
    Last year we inoculated the lawns with milky spore to try to control them. It takes several years, however, to build up enough of the fungus to kill to beetle grubs, and the little devils have to ingest it when the soil is at the proper temperature or it doesn’t affect them.
    Lures are also popular beetle controls, but there are big drawbacks to using most of them. First, there are a lot of beetles around and they can fly. That means lures may bring beetles from all over town right to our yard. That may not sound too bad, but in tests of beetle density, lures attracted a lot of beetles. A half-acre test orchard in Missouri attracted almost 3 million beetles over the course of the summer. Japanese beetles in Wisconsin may not hit those numbers, but rose enthusiasts in Madison have collected loads of them. I’ve seen photos of buckets of beetles from a single yard. That’s way more than I’m going to successfully eliminate ambling through the flowers.
    We’re in the middle of peak Japanese beetle season now, but we’re plucking and soaping and plotting a better path to control. The study that produced the information about beetle numbers also tested a different lure method to reduce them. It involves building a trap out of a trash can and using a dual lure with both sex pheromones and food aromas.
     In theory, the beetles flock to the scents and find themselves snared in the trap. The trick to the method is to locate the lure/traps far away from the plants they protect (at least 30 feet) because the beetles aren’t stupid. Once the munching machines reach real plants they don’t pay the slightest attention to the lures. They just keep on eating where they are, making lots of eggs to turn into a plague of beetles next year.
    I’m happy to try the suggested beetle lure/trap system, which should require an investment of about $150. I don’t quail at the spiders, snakes and other creepy-crawlies, but crunchy bugs like beetles give me the chills. I’m more than happy to go to a system that leaves their disposal in my husband’s capable hands. I hope I can say goodbye to corpse-ridden bowls of soapy water and hello to roses full of healthy leaves.



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Ozaukee Press

Wisconsin’s largest paid circulation community weekly newspaper. Serving Port Washington, Saukville, Grafton, Fredonia, Belgium, as well as Ozaukee County government. Locally owned and printed in Port Washington, Wisconsin.

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