Every year Japanese beetles swarm my roses and cherry tree. I regularly blast them with a spray of water and also will pick them off by hand and drown them in soapy water. What else can I do?

I was going to buy Pyola from Gardens Alive! But what can I do for the long run? I haven't hung Japanese beetle traps because I have heard that they actually aggravate the problem. Which makes sense since when I have hung fly traps to get rid of the flies, I had a worse problem than without them, plus the smell. Yech!

the Japanese chafer beetle traps work well when hung AWAY from the afflicted plants, and emptied on a regular basis. Helps with population control. Milky spore powder will keep the chafer beetles from multiplying where it is applied. After it is applied, it takes about three years to spread out evenly through the soil, but then it is there for the next fifty or so years, so it is only a one time expense. The more people you can get in your area to apply it, the better, since even though the grubs will not be hatching in your yard, the beetles can always fly in from the next yard over. The larger an area that is treated with it, the longer it takes for beetles to enter it. Predatory nematodes are also remarkably effective at treating them, provided you keep the soil moist. They do not winter over in cold climates, so you have to respray each spring, but it isn't any more expensive than spreading chemicals for them. The nematodes also kill flea larvae, tick larvae, bean beetles, grasshoppers...etc...

To deter the beetles, they do not like onions or anything in that family, so planting onions, chives and ornamental alliums all over the area is an excellent control. I have chives and garlic chives (both of which are veryy pretty) around all my roses. Also, interplanting your roses with other plants, like clematis (let a clematis climb up your climbing roses, they benefit from the association and it is quite pretty), lavender, thyme, and other strong smelling herbs will help to deter the beetles, mostly by covering the scent of the roses so that it takes longer to detect them.

Put up bird houses in the area for birds that eat japanese chafer beetles. And be aware that moles LOVE them, they are like candy to them. If you want to plant things that chafer beetles like to eat (anything in the prunus and rose family are susceptible) plant them apart from each other surrounded by other things to prevent the beetles converging for their favorite buffet.

Don't blast the beetles off with water, they'll just be back later. Knock them into the soapy water, or if that doesn't suit, take a japanese beetle trap and open it right next to the rose. The beetles should all fly into it, then you can remove the dead beetles and take the trap away.

The only time I have problems with Japanese Beetles is when my plants are under stress, so do whatever you can to be sure they are growing good and healthy, get a steady supply of nutrients, not a jolt now and again, and the soil is evenly moist so the plants take up the nutrients they need constantly (no moisture, no nutrients).
You are right about not wanting to use the traps. They have an attractant in them that lures the male beetle who release a pheromone that attracts the female who releases a pheromone that attracts the male. The original purpose of these things was to monitor the presence of the JBs and all they do is bring more into the area.

Thanks for the suggestions. I think that Gardens Alive! has the beneficial nematodes and I have a coupon. I'll also try the chives. I think I will also try planting my garlic this year in with my roses. Thanks again.

I found collecting them first thing in the morning was best. When the beetles are still stiff and sluggish; certainly before the sun has hit them and they can warm up. I would hold my jar of "poison" under them and then I could just knock the bugs off the leaf and into the jar. Their instict seems to be to fall to the ground, so hold the jar under the leave. a wide mouth canning jar works well. After a week of that, the problem dissappears. Healthy soil keeps them from coming back and for the plant to endure the bugs I miss.

Those terrible, nasty, bugs are by me also. Out here it is a total investation every year. They will strip my tomatoe plants bare in one night. My roses dont stand a chance. All of the farmers said you got to use Seven. I found one who said the chickens will eat them. NO THEY DONT! Pyola worked but it also killed the plants. I use hot pepper spray. It worked great. Those little beasts flew away the moment the spray was put on the plants. That spray is worth it's weight in gold to me.

Well, at least my soil can't be all too unhealthy. I've only really started gardening, let alone organically. I have been guilty of using those prepackaged, round ball and/or funny colored things in my garden. Even things that have come in an aerosol can. It's like an addiction. But for as much as I have used those "drugs" ( the crack of gardening) I have also used nice healthy food (compost) also. While the plants are covered and look like swiss cheese, they have survived each year. I welcome all the help I can get.