Not sure if spraying them with insecticidal soap will do the trick. Check online to confirm yes or no.

There are Japanese beetle traps. They come with "bait", a little packet that emits the smell of hormones. We found one type-with a hard plastic bottle trap- very effective. Others come with a bag trap, and those were less effective.

it helps to fight them in the soil, where they go through their larval stage. you can get beneficial nematodes (microscopic worms) to water into the soil, which kill those larva and several other pests.

Neem oil works somewhat. What works the best is Permethrim. You have to watch what you spray. It will also kill bees, so I only spray non flowering bushes with it. Otherwise everyday I spot spray the beetle with Permethrim. I avoid spraying the flower. Also it doesn't hurt humans or dogs. But is lethal to cats if it is ingested. I had a cat when I used it and he never went around licking plants or bushes anyway. You will get use to what plant the beetles favor. In my yard it is the knock out roses and pussy willow trees.

Do not use the beetle traps! The hormone in the traps attracts the beetles from your neighbors yards into yours. On the way to the beetle trap they will stop and munch on your plants. Buy some traps and give them to a neighbor down the street to attract your beetles into their yard. lol

I am having this HUGE problem! They are eating all my rose leaves, and rose buds!!!!!!! The poor buds are eaten before they could bloom. I've been picking them off like you and murdering them in soapy water, which i hate doing, but they are wrecking havoc.

Place a beetle bag (pheromone lure trap) in a corner of your yard AWAY from the roses. Not all beetles fall into the bag, but they will be drawn away from the plants you wish to protect.

So I ordered the spectricide bags from Amazon and theyll be here tomorrow. Also picked up some spray at home depot and it doesnt seem to work at all. We have a very large bush that attracts them every year...

I'll look into milky spore and nematodes. how do you know where the larva are to do the nematodes though?

The larva is in the ground, where your infected plants are now. I also treated the grassy areas around the plants. Been beetle free for 3 years now after using the milky spore.

Grubs are the larvae that become japanese beetles. you have to treat your entire yard to get rid of them. the beetle traps work really well in the meantime.

From experience, Do NOT do the traps! Unless you are able to place them FAR AWAY from plants/trees you care about.

I threw my traps away, when I realized they were attracting more beetles!

That's so interesting....the traps really helped us, especially around our blueberry plants. Not quite as successful around roses, but still better than nothing. We do have a lot of space, though. And as I said, we found the hard plastic (I think the brand is Ladd?) Much better than the spectricide plastic bags.

In a perfect world, everyone in my suburban paradise would treat their lawns and there would be no JBs. Unfortunately, that hasn't yet happened. Hanging a bag at the perimeter of my property kills hundreds of JBs which means all those beetles aren't laying eggs multiplying their species. Sure, they don't all go into the bag but I can live with that. JBs are strong fliers: if you grow plants they enjoy, they will come.

Years ago I had an invasion of Japanese beetles and they particularly liked my herb garden. I purchased some of the bait traps and installed near where the problem is. Unfortunately they use 'sex lure' and all of the beetles came to my herb garden. I was very offended to see Japanese beetles humping on my basil! It was like an orgy . . . I'm not kidding.

Unless you are able to place them FAR AWAY from plants/trees you care about.

Well....that's how they are supposed to be used.

It could take several years of application for Milky Spore to work, so it's not an immediate solve. Also, I believe it doesn't work on asiatic beetles (the brown beetles as opposed to the green Japanese beetle) from what I was told by my local nursery. Stay away from traps unless you can place far away. A Master Gardener once told me to plant grapes so they go to the grapevine as opposed to my roses. Grapes are extremely toxic to animals and I have three dogs, so I never planted them. Always trying to find a solution, hence finding your article when I plugged beetles into my search. Been dealing with them for at least 7-8 years now with no luck. Do not squish them - they will emit a pheromone that will draw in more beetles. Drown them in soapy dish water. Best time to do that is early morning or late evening. Good luck as I need it myself.