The adults eat the leaves of birch, linden, fruit trees, roses and purple-leaved shrubs, of which I have several in my yard. Check that – had – in my yard. A purple leaved sand cherry bush is now mostly twigs. The roses were history weeks ago - discovered when we returned home from vacation. A birch tree in my front yard has shed several lawn bags of leaves rendered useless by the beetles’ feeding, despite regular sprayings of insecticide. Dead beetles rain from the tree after each spraying, but are soon replaced by new beetles from elsewhere. A neighbor with a fruit tree has beetles by the hundreds infesting his yard.
If you have a Japanese beetle problem the best thing to do is to spray affected plants with chemical products available at most home stores, such as Sevin, Bayer Advanced Multi-Insect Killer Concentrate and Ortho Bug-B-Gone. Pheromone-activated beetle traps can be used to good effect – a neighbor has captured and disposed of several plastic bags full of the insects over the past week or so.
This is also the time to treat your lawn to kill the grubby offspring that the bugs are producing. Milky spore powder will kill grubs and eggs before they become a problem next year.
Click on pictures to enlarge. Photographs © 2008 James Jordan.