Beetle Battle II – Japanese beetle invasion


     I don’t hide my disdain for the Colorado potato beetles that annually devour my potato crop, but come July, I’m battling a much more formidable foe.

    The deceptively handsome, copper-colored Japanese beetles are out in force, their voracious appetites turning foliage to lace throughout my backyard.

    As obnoxious as they are, potato beetles are at least slower moving, and thus easier to squish than the wily Japanese beetle.

    Japanese beetles have perfected the art of stop, drop and roll, and if that fails, while I’m reaching in for the death kill, they simply fly away.

    Their favorite meals appear to be grapes, hollyhocks, roses and – where we do most of our battle – raspberry bushes.

    Armed with a single gardening glove and a container for whatever raspberries they haven’t devoured, I make a trek to the bushes every evening after work.

    Early evening seems to be the time when they are less likely to fly off and are an easier target for my gloved hand.

    When one or two started appearing on the bushes in late June, this “squish” technique seemed to work, but by now, several of the beetles gather on each leaf and it’s time to move on to bigger things.

    Because raspberry patches should be a place where you or a child can readily eat whatever’s ripe, as-is, I wouldn’t use any chemical means of control. The best approach has so far been to take a small bucket of soapy water  to the bushes – I use liquid dish soap – and knock the beetles into the water.

    Plain water doesn’t quite do the trick, as the beetles can survive, swimming around, for at least several days in it.

    I’ve heard bug experts say Japanese beetles usually don’t kill anything before they end their midsummer’s rampage, but I don’t know that they’ve seen the infestation problem that my backyard seems to have.  Once the beetles ravage their favorite plants, they will move on to almost any others available. They even suck the flowers of my fragrant milkweed to nothing.

    I’m envious of the parts of the country where these beetles have not yet reached. Even areas of Cedar Rapids seem immune to the problem. If you’ve had any luck with other methods of control, please let me know.


5 Responses so far »

  1. 1

    Kim Persons said,

    I haven’t battled Japanese beetles in Iowa, but I waged war in Indiana. What I used to do
    was make traps out of plastic milk jugs or 2-liter bottles. Hang or set them near the plants
    you want to protect with a little water in the bottom. The beetles will wander in, but they
    can’t fly out. When you have collected a fair number, add some more water and make a
    ‘sun tea’ out of your Japanese beetles. It will smell really bad, so handle with care. Once
    your ‘tea’ has brewed, dilute it some more and spray it on the plants you want to protect.
    I’m no biologist, but I read about this in an organic gardening book. The theory is that in
    any random population, some individuals will be carrying disease, and the ‘tea’ allows
    the disease organisms to multiply. When you spray it on your plants, you either infect or
    chase off your pests; I’m not sure which, but either way, you win.

  2. 2

    Jane Davis said,

    We are totally inundated with the Japanese beetles this year in our area of the Hudson Valley (NY State) Interesting idea, as the beetle traps do create that gosh-awful “tea” of decaying bugs. Would that be safe to spray that stuff on edible plants and will affect the more pleasant odor of the (hopefully) ravaged-free roses?

  3. 3

    Cindy said,


    I haven’t tried that method, so I can’t say whether or not it would be safe for edible plants. I ran your question past the Linn County Master Gardeners and they said all they can recommend is hand-picking the bugs or the use of chemicals (though I would not use those on your edibles) such as Sevin.
    Maybe other readers would have some advice.


  4. 4

    rdata said,

    Can’t say I’ve done anything to control the adults but hand pick them. We used milky spore to try to control the grub population, but since we’re totally pesticide free in our Wisconsin garden I’m against spraying to kill adults.

    Japanese Beetles are creepy in large numbers, but if you don’t battle them….

    Thanks for a great post.


  5. 5

    Deb said,

    Homeowners should be aware there is a brand new EPA registered product on the market for protecting gardens from Japanese Beetles, Emerald Ash Borer and as other invasive insects. It just became available in August 2010. The high concentrate, imidicloprid product is called, Optrol. It is the only retail product available that is labeled at the highest rate which is needed for efficacy when treating for these pests. Optrol is a soil drench product which will protect gardens and trees for 12 months and is being sold at independent garden centers and other small retailers through independent representatives. You may be interested to know that Optrol was researched and tested by Purdue University, Michigan State University (among others) before launch of this product. Find out more here:

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