In case you didn't see it there is a very long detailed discussion about this question further down the page. Worth reading through it for tips.

http://forums2.gardenweb.com/discussions/4682250/japanese-beetles-already?n=59

Personally I find Milky Spore very effective but it is a long-term fix directed at the following year crop of beetles and has no effect on this year. Plus it has very specific application times of the year to be effective.

There have many discussions here also about the lures and the general consensus is they only attract more.

Hand picking or knocking them off the garden plants into a container of soapy water is the most common recommendation and effective approach. If you do it after a rain or after you sprinkle the garden they all move to the tops of the plants so are easy to locate and a garden that small should be easy to patrol. Sevin and other highly toxic pesticides need only come into play in cases of a truly major infestation.

Dave

I agree with Dave. They are also easy pickin in the morning if there is a heavy dew. They don't fly when their wings are wet and are easily knocked into the water. They seem to prefer my Asparagus but are also doing a number on the tops of my pole beans. I agree that It is a little annoying when picking beans when they keep flying out into you...just make sure to keep your mouth closed (ask me how I know!!).

I am going to apply Milky spore in about a month in the hopes that it at least puts a dent in their future populations. Nasty little buggers!!

Well, I disagree about traps not being effective. I am a veteran of the JB war. If done early, skillfully placed and emptied [not on or in the ground], using the right lures, it can be very effective when used also with Milky Spore.