Hope this helps!

Here is a link that might be useful: Organic Japanese Beetle Control

Bacillus popilleae, Milky Spore Disease, is a long term control and not very effective for short term and parasitic nematodes can also be used. Put these out in early August about when the eggs will be hatching. But if not every one for miles around does not do that you will get them from distant places.
Day to day control can be achieved by going out early in the day with a bucket of soapy water and knocking the wee buggers into that. These buggers are difficult to control even with that synthetic pesticides.

Here is a link that might be useful: Organic control of Japanese Beetles

I agree that Milky Spore would be the best treatment. In the meantime I like, YES, those traps..very organic. I have also used another aid.
In 2003 I trapped an estimated 270,000 beetles besides killing thousands of others.
After taking a system approach, this year I hand killed 24 beetles; last year 8; and the year before 5.

The Japanese Beetle traps do more to bring the buggers into your garden than anything else.
In many areas of the country the population of Japanese Beetles was quite low, most likely because the weather of the previous summer was not conducive to growing the larva. In the late 1940's researchers from Michigan State came ands put a Japanese Beetle trap in out yard, to see if they were present, We have never had a problem with those buggers before but after that year we did. Those beetle traps are not a good means of control.

Well, kimmsr, I tend to disagree. A dead beetle is a dead beetle and will not propagate further. To skillfully utilize traps early in the season is paramount...before a lot of eggs are laid.

I think your assessment is too simple. If you had more beetles after traps were put out, likely then someone else had less. Beetles will not multiply because of traps. It takes mating, egg laying, hatching into grubs, and survival until the next season.

Glad that you decided to seek other alternatives to control the Jap. beetle in your yard. I'm kind of new to the midwest. It's a new problem that I get to deal with here. Good to hear all of the responses from others OG.
By the way, Bayer just released a statement that neonicitinoids are not the problem with bee dieoffs. What a surprise. Good luck this coming year.
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Glad that you decided to seek other alternatives to control the Jap. beetle in your yard. I'm kind of new to the midwest. It's a new problem that I get to deal with here. Good to hear all of the responses from others OG.
By the way, Bayer just released a statement that neonicitinoids are not the problem with bee dieoffs. What a surprise. Good luck this coming year.
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Pardon me if this was posted and I missed it. Kind of a strange idea but there are lots of web discussions on Japanese Beetles and 4 o'clocks. I don't have personal experience with either Japanese Beetles or 4 o'clocks, but have been researching this flower to grow in my garden this year. It is reported as deer resistant and rabbit resistant, and attracts hummingbirds and butterflies to the flowers.

The flower nectar is beneficial, but the leaves contain a toxin that reportedly kills Japanese Beetles.

There are lots of online catalogs that sell 4 o'clock seeds. I'm planning to grow them this year for the benefits and because I think they are a nice flower. They are considered easy to grow.

Larkspurs, pelargoniums, and tansy might also be beneficial

Here is a link that might be useful: 4 o'clocks attract & kill japanese beetles

I found I had many more Japanese Beetles when I grew 4 O'Clocks than when I did not, just as I had many more when the beetle traps were used than after they were dumped.
The Japanese Beetle traps have a pheromone, an attractant, that mimics that which female JBs emit to attract male JBs and those male JBs that get trapped emit a pheromone that attracts the female JBs. The traps were originally meant to monitor populations of JBs, not to eliminate them.

"Natural Controls
Many kinds of birds such as bobwhites, eastern
kingbirds, crows, European starlings, redwinged
blackbirds, catbirds, songsparrows, robins and grackles
eat Japanese beetles. European starlings, common
grackles and crows eat large numbers of grubs in heavily
infested areas. When grubs are close to the surface,
flocks of starlings may be seen on lawns and pastures
digging up grubs with their long, pointed bills. Crows
frequently pull up small pieces of turf and scatter them
over a lawn as they dig. Moles, shrews and skunks also
feed on white grubs. These animals can damage lawns as
they search for grubs.
Predaceous insects such as wheel bugs, robber flies and
praying mantids occasionally feed on adult beetles. A
few native wasps and flies also feed on beetle adults or
grubs, but they appear to play only a minor part in
beetle control. Several parasitic wasps, flies and beetles
have been imported from the Orient in an attempt to
control the beetle in the United States with only limited
success.
Milky Spore Disease
Milky spore disease is a bacterial disease that kills
Japanese beetle grubs. Spores of this bacterium are
produced commercially and sold under the names of
Doom,, Japidemic, and Milky Spore. The application of
milky spore may reduce the numbers of Japanese beetle
grubs in lawns but beetles will fly in from other areas to
damage plants and crops. Research trials using this
approach to reduce grub numbers in turf have given
very erratic results.
The disease does not kill other types of grubs that
damage turf. See ENT-10, Controlling White Grubs for
additional information.
Collecting Beetles
Hand collecting obviously is not the most effective
method of control, but can be used to protect valuable
plants when beetle activity is relatively low. The
presence of beetles on a plant attracts more beetles.
When you remove beetles daily by hand from a plant,
only about half as many are attracted to that plant
compared to those on which beetles are allowed to
accumulate. One of the easiest ways to remove beetles
from small plants is to shake the plants early in the
morning (about 7 a.m.) when temperatures are low and
the beetles sluggish. The beetles may be killed by
shaking them into a bucket of soapy water.
Trapping Beetles
In recent years commercial or homemade traps have
become a popular means of trying to reduce beetle
numbers. Commercially available traps attract the
beetles with two types of baits. One mimics the scent of
virgin female beetles and is highly attractive to males.
The other bait is a sweet-smelling food-type lure that
attracts both males and females. This combination is
such a powerful and effective attractant that traps can
draw in thousands of beetles in a day. Only a portion of
the beetles attracted to traps are caught in them. Small
number of traps in a home landscape can actually
increase Japanese beetle problems rather than reduce
them."
"Traps may be effective in reducing Japanese beetle
problems if used throughout a neighborhood or in open
areas well away from valuable plantings or vulnerable
crops. In most home landscape situations, using 1 or 2
traps probably will do more harm than good."

http://www2.ca.uky.edu/entomology/entfacts/entfactpdf/ef409.pdf

H.Kuska comment: I grew about 1000 roses in a no spray garden. I used milkey spore, beneficial nematodes, and birdhouses / bird feeders. I did not eliminate Japanese beetles, but the population did reach an equilibrium that I could live with.

Here is a link that might be useful: link to above information

A repeat of something I wrote on GW years ago which might be of interest to some. I was talking with a nursery customer on a beautiful sunny June day; large puffy fair weather clouds drifting overhead. My eye spotted a bit of motion in the lawn grass. Closer observation noted a stream of about 30 Japanese beetles emerge from a hole in the lawn and head straight for the potted roses.

This was interesting. After three days of intense observation of JB behavior I noted the following:

1. When they are ready to emerge from the ground a 'scout beetle' pops up and quickly checks the area and then returns underground. About 60 seconds later the whole group emerges.

2. The beetles only hatch on very bright sunny days roughly between the hours of 11:00 am to 1:00 pm, but most activity is during the period of high noon.

3. If a passing cloud should block the sun for a few minutes the beetles stop emerging until the sun returns.

4. When I would see a scout beetle popping up I raced to the spot, found the little ground hole and applied a quick, small puff of canned insect killer which was enough to kill each beetle as it left the nest. Not organic, I know, but the least invasive way to use chemicals.

5. I also tried sealing each hole with a small rock. The beetles waited out the week to emerge when I had to remove the rocks for lawn mowing. I also placed pots over the holes to trap them and then collected as many as I was able.

So, when JB season begins, take some time to study your lawn watching for the scout beetles to pop up and lead you to the underground nest. With persistence and fast action you may be able to reduce their numbers considerably.

I agree that the hanging traps attract beetles so put them a good distance from people areas, handpicking works but grosses me out. By far the best japanese beetle eliminator is the all natural CHICKEN. These cuties eat all the grubs! No kidding. You wont see japanese beetles and a lot of other garden pests if you allow chickens to free range & their poop is a nice addition too. Just section them off from your new seedlings in the spring/fall.

1)Have had success with mesh fabric purchased at fabric store. I sewed two large pieces together and placed over my Hydrangea at the first sight of japanese beetles. I anchored it down to ground with heavy rocks so the wind would not blow if off. You can also use the tension close-pins. Leave on for two weeks(actually I did three cause I went on vacation) and then throw in your washing machine,line dry and save for next year. They say that the time to discourage beetles in your yard is when they are scouting the best eating and by the time you take the netting off the beetles have moved on. I still have to pick off some beetles twice a day,but there are much less and plants look alot better.
2)Put the Grub-ex down on your lawn between sometime June 26 thru July 15 and make sure rain coming or water in well. Sunlight will lessen effects.
3)They say the Milky Spore works-never tried it
4)Plant stuff that beetles do not like. Local extension can give you the list or I can send link. I got rid of the roses.

Happy Gardener

Grub-X, "Chlorantraniliprole", is not an acceptable method of grub control for any organic grower. It also is not effective, against the grubs, when applied in the spring according to Michigan State and Cornell Universities.

Don't know if a physical barrier like light weight row cover would work for you but, I put those nylon sockies on my peaches while thinning the fruit and they work well to keep the danged GJB hoards from trashing the crop around right now. It is so satisfying to see the pests just dying to chew on a ripe peach but unable to get through the sockie, HAH, take that!!! The sockies also have the added benefit of keeping the Oriental fruit moths out, no spraying for me, ya-hoo!!! Putting all of the sockies on is a real time consuming pain in the backside but once it's done it's done.

I have seen 4 JBs so far this year. If you do trap them [good for you], kill the adults in hot water and then DON'T bury them. or leave them on the ground out back. There are fertilized eggs in the females that soon hatch out.