I keep them off my grapes with neem oil. I don't have any roses so can't say how well it would work with those. Are they eating the leaves or the flowers or both?

In my experience neem oil provides a high degree of control with JB, but this only applies if it is used before the beetles arrive and find preferred food sources. Used after they find it it reduces the feeding, but there will continue to be new ones coming in to take a bite. If you only have a few now and then this might be enough, but if you have hoards of them it might not.

Beyond neem oil, there are traps you can buy, but reports are very mixed. They seem to do a great job of attracting and killing them, but many report the traps attract the beetles to the yard in greater numbers than were there before.

You always have the option of using a broad spectrum insecticide like pyrethrin sprays, but it will kill any insect that visits the rose including the bees so you have to decide if it is worth it.

Good luck, the JB are a real nuisance, but the good news is they are only around for a few/several weeks and then go away.

They are rather slow moving, so you can hand pick them off (or use gloves) and drop them in soapy water, if you don't like using insecticides.

Julie

If you do buy traps, place them as far away from the plants you want to protect as possible. They will draw beetles away from the plants instead of to them.

I suggest hand picking and the trap, saw them at Farm & Fleet. Some say that they attract more JB's into your yard, but I have seen quite a reduction in numbers since I've used the trap. In round numbers I caught about 5 soda cans worth 2 years ago, 2 soda cans last year, and just 1/2 can or less so far this year.
I like it more for entertainment value, it's like watching 5 O'Clock Charlie trying to fly. They have very poor control. When we see one sputtering in for a landing we sit and take bets on how long before they land, etc.

Every forum has its jokester(s), and daddylonglegs you're one of WI forum's greats!

Humor is the best medicine! (even if you don't need medicine)

Julie

I have had excellent luck with Bonide Eight in a hose end sprayer. Sprayed all the trees, bushes and flowers 2 weeks ago. I don't like using insecticides, but it was the only option as last year they just about wiped out everything. I actually had very few this year, what did show up I was able to hand pick. Good news is I think they are about over here in Madison. The ones I do find now are bunched up and mating. The life cycle is eat, mate, then lay eggs in the grass for next years crop.

Actually, if you are angry enough to take the gloves off, you can apply Sevin granules to the lawn and around the plants in August. That will wipe out the grubs.

I just have Rose Chafers here? I have yet to see a JB. I'm over by the Mississippi River, near LaCrosse. Are they not here yet?

While living near Chicago traps seemed to attract more but many avoided trap and ate grapes and roses. Seven does work well if applied often. A vineyard owner there told me that cucumber slices hanging from the vines seems to keep JB numbers down. They should be replaced when dried out. I have not seen any in North Crawford Co., WI.

Cucumber slices would certainly keep them in a pickle.

I'm in Oak Creek in southern Milw. cty. and I've never seen any yet. Of course now that I've said that, we'll have hoards of them next summer.

Kat