Please indicate the recommended treatment of Japanese Beetles in order to eliminate complete destruction of a tree, particularly large older trees which are under attack.

This excerpt is taking from Ohio State University: Control of Japanese Beetles and Grubs in Home Lawns.

The adults can be controlled by spraying susceptible plants with insecticides. Over-the-counter pesticides available for this include: acephate (Orthene), carbaryl (Sevin), and several pyrethroids - bifenthrin, cyfluthrin, deltamethrin, lambda-cyhalothrin, permethrin, and others.

Applications of imidacloprid (e.g., Bayer Advanced Tree & Shrub Concentrate) generally need to be made 20 days before anticipated Japanese beetle adult activity.

During the heavy adult activity periods, sprays may be needed every 5 to 10 days.

An additional source, from the USDA Animal Plant Health Inspection Service:

http://www.aphis.usda.gov/lpa/pubs/pub_phjbeetle04.pdf