Japanese beetles can be a challenge at this time of year, eating every rose in sight and making an unsightly mess. Staying ahead of them – or even just keeping up with them -can be a lot of work.
There are gadgets out there that some swear by, like the pheromone-emitting bags that lure the beetles into their trap and kill them. I have no direct experience with these, but have always wondered if attracting Japanese beetles into your own yard is a good idea. Assuming the traps aren’t 100% effective, isn’t there a chance that you could end up with more beetles than you would have had without the trap? (Or is the trick to convince your neighbors to get it…) Anyway, if it works for you, great. No need to argue with success!
Other methods of getting rid of them are a little less palatable to the squeamish, but do work if you have the time and the patience. These consist of squishing them by hand (yeah, I know…) or knocking them off the leaves into a container of dish soap and water, where they drown.
There are additional things that you can do to help. Keep your plants healthy so that they are able to withstand an attack better. You can also try planting plants that they don’t tend to like in amongst your roses, such as Nepeta, and Chives, Garlic. And as a last result, contact someone with a pesticide license to come and deal with the grubs.
An integrated approach is probably best, as it is with most things. Good luck!