Japanese beetles are a real nuisance. They come back every year and can wreak havoc in your yard. Their damage is easily recognizable - skeletonized leaves or total defoliation. If you like to grow roses, you're probably quite familiar with these little buggers. They love rosebuds (which they tend to eat from the inside out) and all members of the rose family for that matter, including Rose of Sharon and Cherries.
Prevent.
Although these solutions won't immediately rid your yard of Japanese Beetles, they are the best solution to controlling the population. The grubs that you find in your lawn may grow up to be Japanese Beetles. Make sure that you're preventing all kinds of grubs first and foremost.
Trap.
These work great if your have a larger yard. Place a Japanese Beetle trap in your yard away from their desired plants and watch the bags fill up! The traps trick them into thinking a mate is present. They fly in and get stuck in the trap. You just have to pull the bag off and throw it away!
Defend.
Spraying with pyrethrin based insecticides is a safe and effective method of controlling Japanese Beetles on vegetables and ornamentals. Neem oil can be a great antifeedant.
Hand Pick.
Japanese Beetles are pretty slow moving. Go out in the morning when they are less alert and pick them off your plants (don't worry they don't bite) and drop them in a bucket of soapy water.