Another weapon in the war against Japanese beetles?

Photos courtesy of Lynn Hunt.
The English rose St. Swithun didn't have a chance against a gang of Japanese beetles.

As I mentioned in my previous post, Meet the Beetles, I don't use heavy-duty insect sprays in my garden. I once accidentally zapped a praying mantis with an insecticide and was so upset about it, I’ve been extremely careful ever since. I’m sure the birds, ducks, and beneficial bugs in the area are grateful for my caution.

Having said that, there is something so disheartening about seeing Japanese beetles devour a favorite rose, I feel compelled to try anything (blowtorch anyone?) to make them disappear.

So yesterday I grabbed a spray bottle of window cleaner and went beetle hunting. I had hear a rumor that window cleaner might zap Japanese beetles.

I sprayed the pests on four or five roses and waited to see what happened. Almost immediately, several of them simply took off. One brazen beetle flew directly at me and had to be forcibly removed from my T-shirt. Others continued munching happily as if nothing had happened.

I set off for my afternoon walk thinking the experiment had been a complete failure.

An hour later, the situation changed dramatically. Many beetles lay lifeless on the ground. Others were wandering around erratically and some were dead inside the rose petals where I had sprayed them earlier (see second photo above).

The rose blooms and foliage did not appear to be affected, although today I noticed that Tess of the d’Urbervilles had a bit of bluing around the edges. In addition, it hasn't been as hot here as it usually is, which can affect results when you're spraying.

I suggest that if you want to try this idea in your own garden, you test a small area first to make sure you don't end up with crispy petals and leaves.

The window cleaner  I use contains ammonia, and I am wondering if it is the ingredient that sent the beetles to their doom. Entomologist Michael Klein speculated it might be a possibility.

I’ll never know what happened to the beetles that flew off, but if they met an untimely fate later, at least they were shiny and sparkling clean.

PSSST: My good rose-judging friend, Jim Diggs, tells me that sparrows take care of his beetle population in Richmond, Va. He reports that the birds knock the beetles to the ground, then lap them up. I must have a word with my sparrows. They are falling down on the job here in Maryland.

Find more posts from The Rose Whisperer, Lynn Hunt, at our blog archive.

More Monitor gardening: The main Monitor gardening page. Our RSS feed.

You may also want to visit Gardening With the Monitor on Flickr. If you join the group (it's free), you can upload your garden photos and possibly win a prize. This month's photo contest is veggies. Feel free to join the discussions and get answers to your gardening questions.

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