Buy those hanging hormone traps. They work pretty good. My roses, basil and marigolds are destroyed. They are everywhere this year. Every year in late June/July.

Thanks, tomgrower! They haven't attacked my basil yet. Maybe that's because they like the berry bushes better, though I never thought of them as a "trap crop." I noticed ladybugs almost as soon as aphids arrived a week or two ago, but so far the wildlife seems to leave the beetles alone.

It's a ritual in my garden twice a day or more to walk around with a jar of soapy water (2 drops of dish detergent in a few inches of water). We put the jar carefully under the beetles and tap the leaf, and they naturally drop into the jar. Easy. This doesn't work in midday, when they will just fly away.

I am especially vigilant around my roses because they will ruin a bud in a few hours.

I don't know how you feel about Milky Spore (bacillus thuringensis?), but I believe that application of this to my lawn and rose beds 2 or 3 times a growing season has definitely reduced the number and intensity of JB's in my garden.
Many friends here in the Hudson Valley have stated that this has been a horrendous year for JB's, but I have had only moderate infestation. My goddaughter's roses were covered with them, I just wanted to vomit when I saw them so bad.
The hanging hormone traps help, too, but hang them far away from the plants you most want to protect.
And learn to pick and squish!

it's my understanding the natural hormone traps may actually attract _more_ japanese beetles to your area. last weekend, on 98.1 (wkze) saturday garden program, the guest said that milky spore should be applied in the autumn? or spring? i forget, now. but i think he also said that ideally, it ought to be applied by your neighbors as well. in the end, i don't think he gave any sure-fire methods of dealing with the japanse beetles. i did walk around my yard with a coffee tin, filled with a little motor oil. i tapped the beetles with the lid, and they just dropped in. but, as i'm only there on the weekends, i picture them having their fill the rest of the week...

--robbie--

You apply Milky Spore 3 times: spring, mid-summer, autumn. Yeah, it helps if your neighbors do it, too, but in my case neighbors have a lot of paved area and very shady area, not prime JB bedding grounds. One gal on GW wrote that she applied it to the neighbors -- sheesh! Some folks think it's pricey, but the way I see it, it also is lawn insurance (fewer divots dug up by my friendly neighborhood skunks), veggie insurance (lots of other beetles breed the same way and infest cukes and zukes), and flea treatment, all-in-one.

I think one application is sufficient and do it in spring when the grubs are in the ground. Most people around here applied it years ago when there was a factory manufacturing it in Clinton Corners. I've only seen a few beetles and the birds generally take cae of those so I don't bother. I don't have a lawn but my neighbors do. You can use milky spore AND hang beetle traps at the edge of your property but don't grub proof the lawn and also use milky spore since the bacillus can't survive unless it has grubs to work on. Sevin kills beetles but you have to keep at it.

I got TONS of them this year but I've done my part, I caught and killed about 2 quart mayo jars full of them over the past few weeks in my trap. Town of Poughkeepsie area. The trap DO work well, I've been using them for years. Place in a SUNNY spot about 30 feet or so away from plants you want to protect. I noticed they like burning bushes a LOT and my Wisteria. I have a plastic type trap (Made by Teece) and when it gets 1/4 full I get a bucket of HOT water with dishwashing liquid and submerge the trap and wait half an hour. Dead beetle are the result!

Tom