Wednesday

How to Get Rid of Japanese Beetles

Closeup of a Japanese Beetle
It's that time of year again: You know, the time when Japanese beetle grubs make their way out of the soil and begin feasting on your delicate garden plants. Japanese beetles are opportunistic feeders that damage commercial as well as backyard crops and ornamentals. They're very hard to beat, too. We'll get to some methods for dealing with them in a minute, but let's talk about the bug a bit first.

Bug Battles, Why the JB Is Winning


Japanese beetles were first introduced to the U.S. back in in 1916, and they've been trouble ever since. The first beetle immigrants made landfall in Riverton, New Jersey, and have become established in some 30 states -- at last count. Their westward expansion shows no sign of stopping. They have few natural predators here and are voracious, relentless and adaptable. When they find a food source, they can denude blossoms and fruits in hours. Pictures of writhing masses of beetles clustered on plant stems sagging under their weight aren't an exaggeration. The visuals are unsettling, even if you aren't a gardener. If you enjoy maintaining a little patch of green, the reality is heartbreaking.

Frequently Asked Questions and Desperate Comments Addressed


Why do Japanese Beetles arrive at the same time every year? Japanese beetles emerge from the soil in spring or summer on a predictable schedule. For most areas of the U.S., they start causing problems beginning in May or June and continue till fall. Your neighborhood garden center or USDA Cooperative Extension Office (a free service; click to find the location nearest you) can tell you when they're due in your area. The information should be accurate to within a week or so.

I've never had problems with Japanese Beetles before. Although JBs can eat just about anything, they like some plants more than others. This includes berries (grapes, blueberries, raspberries), corn and roses. If you've added new plants to your garden and are having your first JB visitors, chances are you've introduced a plant they find particularly tasty. While they're visiting, they will also explore other vegetation on your property. Getting rid of the plants that attracted the beetles could help reduce their population and give you a break. For a list of plants JBs like a lot, visit: What You Need to Know about Getting Rid of Japanese Beetles 

One day there were just a couple and the next there were hundreds. If you had problems with JBs last year, they probably overwintered in your soil or under your lawn. This means they'll emerge in clusters near your plants, the handiest food source, while supplies of tasty greens and flowers last. If you deal with them this season, you'll likely have fewer problems next year.


Japanese Beetle Pupa
Their numbers are increasing a little every day. After they emerge, JB scouts perform neighborhood recon to find future feeding grounds. Increasing populations over time may mean the word is out about your garden. If you act fact, it might be possible to trick scouts into bypassing your plants by leaving a scent trap. This is done by catching some of the very early beetles (within a week or two of their emerging), killing them in a bucket of soapy water and leaving the water near the most likely target plants, plants they like to eat. The smell of dead beetles will help discourage newcomers. The instinct to feed is strong, though, so this method rarely works late in the season or if the beetles are already entrenched in your garden.

My neighbor (or I) put up Japanese beetle traps, and now there are more beetles than ever before. In theory, JB traps sound like a great idea. Attract the bugs with pheromones, trick them into a sticky box and watch them die, die, die. Tests conducted by the U.S. Department of Agriculture weren't that encouraging, though. They found that traps catch three out of every four beetles they attract. The rest are free to explore your garden. If they like what they see, they'll invite their friends.


How do I get rid of them for good? See the suggestions below.

How to Deal With Japanese Beetles


Dealing with Adult Japanese Beetles Today -- If your blueberries or other delicate plants are under attack by JBs today, pesticide may be your best bet in the short term. Malathion is an effective choice for killing adult beetles, but there are others. Ask your nurseryman for suggestions. Be aware, though, that poison isn't selective. It will kill beneficial insects along with the JBs. To protect honey bees, which are having a hard time these days, prefer spraying in the evening after busy bees have returned to the hive.


Pesticides only work for a while. Poison kills Japanese beetles, but to be effective it should be reapplied according to the manufacturer's directions throughout the season.

Organic Solutions for This Season - If you want to go the organic route, put your garden gloves on, catch batches of the adult pests in your angry little fists, and dump them into soapy water. They'll drown -- and that's fewer of them to contend with. You can also knock them into the water bucket -- after you have some experience under your belt. (There's a bit of a technique to it.)

If this seems horrifying, you'll get used to in about 10 minutes or so. The only good Japanese beetle is a dead Japanese beetle.  I've caught and submerged over 60 beetles within a 10 minute period in my day -- and I wasn't even trying that hard.  JBs become active at around 9:00 a.m. in my area. A little investigation will show you the best time to plan an assault of your own.  Thinning the herd works, but it requires an ongoing effort. JBs don't bite, which is the only nice thing I have to say about them.

Companion Planting -- To reduce your exposure, one organic option is to add plenty of plants JBs tend to avoid. What follows is a list of plants that repel Japanese beetles somewhat. Placing them near attractant plants may help balance the scales. Here's how it works: In spring when there are lots of feeding locations to choose from, beetles may avoid your garden -- for the most part -- if you add enough olfactory discouragement in the form of stinky plants (from a beetles perspective). Many of the best varieties are strong smelling herbs. Once JB scouts have written you off, they may never circle back around to you in large numbers. Start with these plants:

Japanese Beetle Larva
  • Artemisia
  • Catnip
  • Chives
  • Chrysanthemum (white)
  • Citronella
  • French marigold (may attract spider mites, though)
  • Geranium, especially scented varieties
  • Larkspur
  • Leek
  • Mint
  • Onion
  • Rue
  • Tansy

Revamp Your Garden With Alternative Plant Varieties -- If you're starting a new garden or revamping an old one, choose plants Japanese beetles usually ignore. This can be tricky, and a little discouraging, since many popular garden plants seem to be JB favorites. Still, there are good options around, including:
  • Begonias
  • Boxwood
  • Caladiums
  • Lilac
  • Dusty miller
  • Euonymus
  • Flowering dogwood
  • Forsythia
  • Holly
  • Hydrangeas
  • Juniper
  • Magnolia

Planning for next year -- If you're under attack this season, you may be doomed to fight the good fight until fall. That doesn't mean next year has to be, "Japanese Beetle Attack! - The Sequel." There are measures you can take to kill grubs in your soil over the winter. That way you'll be starting with a clean slate come spring. There are a number of products that can help with this, including pesticides designed specifically for JB grubs, and more organic options like introducing nematodes to your soil or using milky spore bacteria to kill them. (Nematodes are beneficial, microscopic worms that feed on grubs, killing them as they lay dormant over the winter or before they emerge in spring.)

For more information about what I've discussed above, visit other JB posts:

What You Need to Know about Getting Rid of Japanese Beetles 

Get Rid of Japanese Beetles With a Homemade Repellent

Control Japanese Beetles Naturally

Japanese Beetle Control (or Controlling June Beetles)


There are quite a few ways to approach the problem of JBs in the garden, but none of them are simple or totally effective. Even if you apply pesticide to an existing infestation, change you landscape somewhat to make your property less attractive to them and adopt measures to eradicate grubs, you may still encounter Japanese beetles in the garden in the future. Their populations should be more manageable, though, and the damage they inflict less extensive.




Doesn't it just make you want to cry?


Photo ReferencePhoto 1 - By USGS Native Bee Inventory and Monitoring Laboratory from Beltsville, USA [CC-BY-2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons http://commons.wikimedia.org/wiki/File%3APopillia_japonica%2C_unknown%2C_face_2012-07-24-15.09.14_ZS_PMax_(8430127397).jpg, http://upload.wikimedia.org/wikipedia/commons/0/0c/Popillia_japonica%2C_unknown%2C_face_2012-07-24-15.09.14_ZS_PMax_%288430127397%29.jpg (close up)
Photo 2 - http://commons.wikimedia.org/wiki/File:Jbadult.jpg, Public Domain (adult)
Photo 3 - http://en.wikipedia.org/wiki/File:Jbpupa.jpg, Public Domain (pupa)
Photo 4 - http://commons.wikimedia.org/wiki/File:Jblarva.jpg, Public Domain (larva)

Photo5 - By Luke [Public domain], via Wikimedia Commons (mating pair) http://commons.wikimedia.org/wiki/File%3AJapanese_beetles_on_wild_grape_vine.jpg   http://upload.wikimedia.org/wikipedia/commons/e/e4/Japanese_beetles_on_wild_grape_vine.jpg 
  

1 comment:

  1. Oh, I hate those pesky beetles! And the larvae seem to attract skunks. I have had some success with treating the lawn for the larvae, but it takes a while.

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