In only one day, Japanese Beetles have decimated a plum tree & sand cherry tree; moving on to the apple trees & silver lace vine along with hibiscus & rose of Sharon! I've never seen anything like it. While picking hundreds, there are hundreds more. I will have little left in my garden & landscape if this continues thru July & August as the K-State Bulletin states. While I'm not a fan of chemical spraying, it's impossible to hand-pick them all. What is the best solution for this new trouble maker & why don't the birds eat them? Thanks, Gwen
Birds like crows, grackles and starlings do eat Japanese beetles, both the adults and the larvae, but when populations are heavy, the birds probably can't keep up.
There are a number of chemicals that will kill the adults, carbaryl, bifenthin, cyflutrhin, horticultural insecticidal soaps, to name a few. But when shopping for a chemical to spray, be sure to make sure Japanese beetles are mentioned on the label. Frequent monitoring for new generations, and repeat spraying will be necessary.
You mention the KSU bulletin, which you can again access here. Included n it is a complete list of chemicals, as well as a list of plants that are particularly tasty to these pests. an interesting note in the bulletin is that moisture is critical for the development of the embryos, which may explain why you have seen them in such devasting proportions this year.
Best of luck, Carole - Johnson County Extension Master Gardener