Sometimes you can plant "sacrifice" plants, that the beetles tend to eat first. We were talking about this over in the veggie forum, how some pole beans are more attractive to beetles than others, so they plant the vulnerable ones to try to keep them away from the others.
I'm sorry I don't have better solutions for you. I hate them too. They have eaten some of my water garden plants. They spend their days in my lotus blossoms. Blasphemy!!!
Lotus flowers are so beautiful and peaceful looking. Now they're filled with those wretched beetles.

I have never had Japanese Beetles, until this year. There's basically nothing left of my Corylus americana.

I agree about the "sacrifice plants." Plant some expensive rose hybrids! But then be sure to "harvest" the beetles on the roses so they don't multiply for next year.

I have great fun going out in the early mornings with a bucket of soapy bubbles and knocking the beetles into it to drown.

In the cool mornings (and sometimes at dusk), the beetles are very sleepy -- almost comatose -- and they'll just let go of their leaf and roll off into your bucket. Don't use too much water, or the bucket will get heavy fast!

Later that afternoon, strain out the water and tie the beetles up in a couple plastic bags and throw them away. Otherwise, they start to smell bad after a few days.

Probably best not to use lure traps -- it attracts more beetles, and the ones who don't fly into the trap hang around together on nearby plants and mate, thereby making thousands more beetle grubs for next spring!

Also, look up "milky spore powder". I *think* it's a natural, organic fungus that reduces jap. beetle grub populations over the course of a few years. And I *think* it's selective for jap. beetles and doesn't harm other grubs. Best to look it up; don't just take the word of some goofy stranger on the internet!

Cathy's right about the sacrificial lamb idea, but the trouble is, these guys seem to have trouble deciding from year to year which plants they like best. Oh it's a sure thing they will seek out fruit trees--anything in the rose family- and hibiscus and so on, but either we don't have the numbers that we did last year (yet) or else they just really have a hankering for a berry because I just finally gave up and quit worrying about freezing the blackberries this year. They are gone, nibbled to stubs and the foliage too.. We had a huge crop coming on with all the plentiful rains and when I first hit the patches I was speechless. In a few areas you would think you were looking at a winter scene because all that was visible to even remind you that you WERE in a berry patch were the naked canes.
The good news is that I have not had a SINGLE beetle on any of my yard plantings, and this is within sight of the berry brambles. Maybe this good news is extrememly short lived, as I can only guess where the beetles will fly to after the bberries are depleted.

THe traps DO work but they need to absolutely stress to the consumer the need to set them up correctly. I think that is the number one thing I am hearing right now, the fact that people are erecting traps in their yards and then experiencing a population explosion when they start to work.
I know of several people who customized their traps to utilize garbage bags instead of those ridiculously small bags they come with, and even then you can't just walk away and forget about it, it HAS to be monitored and cleaned out.

Aren't JB grubs sod-dwellers? I was under the impression that like so many other "white grubs" they prefer lawns and grassy areas to develop during the first stages of their cycle. Maybe we now have another reason to tell people to get rid of their sod and go native.

I can attest to the fact that they don't go for the same things every year. Last year they turned huge canna plants to lace, and ate a lot of raspberry leaves. This year their favorite plant seems to be my "Kiss Me Over the Garden Gate" which they have giant orgies on. Here is a picture of what they do to it.

They are also munching on raspberries, morning glories, coneflowers, roses, zinnias, and surprisingly rhubarb (thought the leaves were poisonous). But, they have not touched the newly planted viburnums and blueberries. I read they loved those last year right after I planted them.

I am going out and hand picking them off into soapy water several times a day and getting dozens almost every time I have gone out for the past several weeks. We don't water our lawns at all and just let it got dormant if there is no rain. Maybe they are overwintering in a neighbors golf course like lawn and heading over to our house come feeding time. Not much of the rest of the neighborhood has much in the way of gardens. I normally don't kill bugs and had a little guilt at first, but they pushed me too far :)

BTW...forgot to add this about milky spore.

Yes it is very effective at keeping the grubs killed off but you have to be dedicated to doing it right for it to work. I know that it takes several years to build up to effective levels and that it can be rather expensive (from what my MIL told me).
Personally I think if you have neighbors with large expanses of turf then it would be a waste of time and effort and money unless they treat for the grubs too. THe adults are like coonhounds...they can't read signs.

This is only my second year in having Japanese Beetles.

Last year their favorite plant was Virginia Creeper, but then they went for my Maple tree and defoliated it completely.

So far this year (crossing fingers), they are only on the Virginia Creeper.

Funny though, I have not seen them in a few days.

I was going to try to get rid of the VC, but I think I will keep it now as a sacrificial, sounds like a good idea.

My sacrificial plant used to be a porcelain vine. In fact, I never had JB's until I got that vine. Then I found out it was invasive, so we got rid of it, and the JBs moved to other things.......like our Linden tree. It completely skeletonizes it every year, but it keeps coming back.
They were late in arriving this year.
How come everything awful on my property, has the word "japanese" in it? I'm not insulting the japanese.......I just think that we are a very similar zone as them, but haven't developed the natural controls that have developed over time in Japan.
They completely ate my pickerill rush in one of my water gardens, but didn't touch them in another one.
They started eating my pole beans and I yelled at them really badly, and it seems to have slowed them down.

Yes, I'm hoping the "season" is over for them; haven't seen one in a while. This year they were very attracted to the Decumaria barbara that I had climbing on the fence; it was nice because you could stop by there every morning and kill a bunch. Last year they like the Illicium floridanum, but I haven't seen one on it this year.

Unfortunately foreign pests do well here because they didn't bring their natural controls with them. And many foreign plants do well because they didn't bring their pests with them! Sheesh.

I feed the JB to the gold fish and frogs in my pond. The gold fish love them and eat most of them before the frogs get a chance.

I do not spray poison as I have milkweed for the monarchs and other butterflies. In fact I never use any poison for fear of killing hummingirds and other wildlife.

The JB have destroyed all of my rose bushes, and my cherry tree. I try to keep the numbers down by hunting them and feeding them to the critters in the pond. I think milky spore is your best bet. I also read that robins and catbirds will eat the JB, but I have never seen them do it.

The JB also eat the milkweed flowers, but I think it kills them LOL!!! I see alot of dead ones hanging from the flowers.

Good luck getting rid of the nasty bugs.

Karen