There was a discussion here about them last month, I think. I had a terrible time with them too, and found something called Milky Spore, a beneficial nematode that eats their larvae. It doesn't work right away, but it does finally work and stays working a long, long time. Plus, it's natural. No poisons. I got mine through GardensAlive! (Try a search on GardensAlive!) under the name "Beneficial Nematodes Hb". They also sell something called "Neem-Away" which is a natural insecticide that doesn't harm the good insects, like bees.

Whatever she does, do NOT let her get those Bag-a-Bug things. I tried those and I swear they attracted every dreadful bug in the owrld into my yard for a big party, plus, beautiful butterflies were climbing into the bags as well, which broke my heart.

This is a long story, but when I moved into my town 9 yrs ago, didn't garden the first yr,did a veggies the second and both flowers and veggies ever since. My neighbor (who my mom bought the house from next door to me) was a chemical, salt, only liquid fertilizer, etc. user and every year she'd say the bugs were getting worse, so she'd use more or higher doses or more often. She said she was getting the bags and I tried talking her out of it... for 3 yrs she used the bags and the beetles were ferocious!!!!!!
Now, it's technically been 3 summers since she's not been in the gardening practices, and this year so far, *I know, I might have to kick myself for saying this but as of this date, I've seen 3 Japanese beetles......
Now, I know we've had a wierd spring and summer so far, butttttttt................
only 3..........and I never had any until she started really using those bags........ actually I can't just say it was her, because I remember the summer before she got her bags, that we had taken several strolls through the streets and remarked to each other how many people had the bags and multiple bags as well.....and she jumped on the wagon and got several too. But I've noticed not one bag here in town this year.
I am wondering if everyone has come up the same conclusion about the bags as well.
I can only hope!! They are a pain, they stink, they are some what expensive and I don't like chemicals myself.....
Thanks for the soapbox!!LOL