Has there been any improvement in the technology for removing Japanese beetles? We have rosebushes and a large grapevine, and by August we’re inundated with Japanese beetles. When my father had them, it was our daily duty to pick them off and put them in a can of kerosene.
Your father had the right idea by collecting Japanese beetles every day, because it stops signals given off by feeding beetles that attract more beetles: Handpicking can reduce overall feeding by half. But instead of kerosene, a couple of inches of soapy water in a pail or bowl is the collection method generally recommended.