Japanese Beetle Control (or Controlling June Beetles)

I hate Japanese beetles (popillia japonica Newman) sometimes spelled Japanese beatles -- if they're musical, I guess -- or referred to as June beetles.

When you're battling these relentless garden pests, you probably despise them, too. I've seen a horde of Japanese beetles completely deconstruct a rosebud in well under a day. I wish I could offer more late term advice and comfort. When it comes to Japanese beetles, though, getting at them early and taking the time in fall to lay the groundwork for next year seems to work the best. On hearing this, I've been told by grumpy readers determined to find a quick solution that I'm no help at all (cue the sound of a door slamming).

When and How Did Japanese Beetles Get Here?

One big problem is that Japanese Beetles aren't native to the U.S. and have few natural predators here. Even worse, they love the weather and can find plenty to eat. They've been around since 1916 after arriving from Japan in a shipment of goods bound for a nursery in southern New Jersey. (It's pretty amazing the experts can actually pinpoint this.) Today, they're very active in 25 U.S. states, most of them east of the Mississippi.

You may think the infestation decimating your blueberry bushes is bad, but the fact is Japanese beetles are also a threat to commercial growers and have an impact on the prices we pay at the market as well as the types and quantities of pesticides on some crops.

Before I moved to the Midwest from the West Coast, I'd never seen a Japanese beetle before, although I'd warred with snails, slugs, aphids, tomato hornworms, sowbugs, centipedes and earwigs -- ugly, nasty bugs all. The first beetle I saw looked like something from the inside of Aladdin's cave. I thought it was beautiful -- an iridescent green and bronze that looked lovely in the heart of a pink rose. Within 48 hours, my pink rose bushes were in shreds, and every morning after that saw more beetles winging their way into my yard. These pests emerge from the ground about the same time every year (for your area), typically during June, which means there isn't a sign of them one day and they're everywhere the next.

I've Never Had Problems with Japanese Beetles Before.  Why Now?

If you've been spared problems with Japanese beetles on you property in the past, it can be hard understand what's happening when they come calling. Often the trigger is the addition to your landscape of a plant on their culinary wish list. Japanese beetles are opportunistic feeders, but they give preference to locations containing their favorite foods. The good news is you can reduce your risk of problems by avoiding these plants. The bad news is that many of their favorites are landscaping and garden favorites, too. You can visit my post: What You Need to Know about Getting Rid of Japanese Beetles  for a list of plants they prefer. It's enlightening (scroll down to the second half of the post to access the list).

Why Is My Garden Being Targeted by Japanese Beetles?

Your property may also be getting the overflow from a neighbor's plants, or even beetles being lured into nearby gardens by beetle traps. According to information released by the U.S. Food and Drug Administration (FDA), commercial traps fail to catch around 25 percent of beetles attracted to them. That means those surviving bugs are going to find food nearby if they can. If you haven't been affected before, this can be a big, unhappy surprise. Japanese beetles are voracious, relentless and can do a lot of damage in a short period of time.

Once beetles are active on your property, it's a good bet their grubs will take up residence to overwinter underground in your lawn and flowerbeds in fall, making it much more likely you'll be targeted again next spring. They like to wake up next to a reliable food source.

There are measures you can take now and before winter to protect yourself.  The post referenced above explains them in detail and also recommends a few popular pesticides that can help, so I won't repeat the information here.

Help! What Can I Do Today to Combat Japanese Beetles?

In the meantime, you can still keep their numbers down by using pesticide or by far my favorite method, shaking, knocking or throwing the bugs into daily buckets of soapy water.  They don't bite, and after the first few, the ick factor all but disappears.  I wear lightweight garden gloves and have a pretty good success rate.  It's easy to develop an effective technique quickly.  All it takes is a bucket, soap, water and the will to win. Consider it an organic approach -- and a good stress reducer.

You'll also find that Japanese beetles tend to become active at about the same time every morning (mine start in at about 9:00 a.m.). If you're at home, you can get a jump on the day by eliminating as many as possible early.  I've found this can sometimes keep their numbers down and help avert a feeding frenzy.

References

USDA Managing Japanese Beetle: A Homeowner's Handbook http://www.aphis.usda.gov/publications/plant_health/content/printable_version/JB3-07.indd.pdf


Photo 1 - By Vmenkov (Own work) [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/0/0c/Japanese_beetle_eats_peach_leaves_P1000159.jpg http://commons.wikimedia.org/wiki/File%3AJapanese_beetle_eats_peach_leaves_P1000159.jpg