Japanese and Oriental Beetles
Since we only have a small infestation of beetles at this point
we've been successful in controlling the population by picking the beetles off the affected plant, and killing them. If you don't care for crushing these beetles in your fingers, a great alternative is putting them in a bucket of soapy water where they will suffocate.
In the event that you're seeing a more serious infestation other organic methods are still available. Biological agents such as beneficial nematodes, and milky spore will control beetle populations by disrupting different stages of their life cycles. Neem oil can also be used to suppress the appetites of the beetles.
If you anticipate a problem with these beetles, and would like to look more at prevention there are a few methods to consider. Avoid growing the beetle's favorite plants, which include varieties of eggplant and strawberries. Make sure produce is harvested in a timely manner. Rotting and overripe produce is one of the things that attracts these beetles.
Something to avoid are the pheromone traps so commonly associated with the control of these pests. While these traps do attract and trap a large number of pests, they also miss some. If trying to control these beetles in a relatively small area, they will end up attracting more beetles than they actually trap. So quite often, these traps can leave you with a larger pest problem than you began with.