Try neem oil, mix the concentrate and spray as directed. I'm not going to just guess if you have genuine Japanese beetles of a particular type or June bugs -- they are not the same thing. But neem oil will affect their reproductive process regardless. It's a bit more "natural" than sprays and powders but may not make much of a dent in the population if there's a lot of them already. I've been fighting the Japanese lily beetle for going on four years now. They destroyed all my true lilies. Bloomed, but weak flowers, lasted barely a day, leaves mangled, spindly plants returning the next year. This year, I sprayed with neem oil very, very early in spring, just as the lilies emerged. Kept a watch. Ultimately caught 3 beetles, squished them. So far, no more. I'll find out soon if I managed to stop the reproduction before it reached a level that can't be contained. In fact, they get another spray tonight. (Don't use neem in the day.)
Try neem oil, mix the concentrate and spray as directed. I'm not going to just guess if you have genuine Japanese beetles of a particular type or June bugs -- they are not the same thing. But neem oil will affect their reproductive process regardless. It's a bit more "natural" than sprays and powders but may not make much of a dent in the population if there's a lot of them already. I've been fighting the Japanese lily beetle for going on four years now. They destroyed all my true lilies. Bloomed, but weak flowers, lasted barely a day, leaves mangled, spindly plants returning the next year. This year, I sprayed with neem oil very, very early in spring, just as the lilies emerged. Kept a watch. Ultimately caught 3 beetles, squished them. So far, no more. I'll find out soon if I managed to stop the reproduction before it reached a level that can't be contained. In fact, they get another spray tonight. (Don't use neem in the day.)