Japanese beetles worse this year than I ever recall, anything I can do this late in season?

Question

I thought Knockout Roses would be immune to these hated beetles…how wrong could I be?? I have 4 expensive plants; but during summer, you would hardly guess that they exist. They only have a brief chance to bloom in spring, then maybe in fall. My mother (R.I.P.) used beetle traps long ago, with mixed results. I have never seen so many beetles as I see this year! Devouring the roses, and when I realized they were ravaging my beloved hand-planted zinnias, I was shocked. Never saw that before! My zinnias can reach 4-5 feet tall when unmolested. This year they probably won’t be more than half that height. I have several hardy hibiscus which fortunately are so hardy that the beetles don’t really hurt them although these shrubs are a favorite of theirs.

As photos are encouraged here…I just made a pic of some of the sad carnage in one of the zinnia patches.

Is there anything I could do to get some control over these hated bugs other than picking them off by hand, etc.? They bite and I fear them! Besides, I work away from home and don’t have free time to kill bugs one by one.

Answer 1

What a pest! Some people have resorted to hand-held vacuums to scoop up the bugs. (empty into soapy water) As far as control agents, please be mindful that beneficial insects are also affected. The least toxic insecticide is pyrethrum. Another recommended treatment is neem oil. As always, read and follow instructions thoroughly. There are more toxic approaches. Do an internet search for “contact insecticide for Japanese beetles”. Two are listed in this article: https://www.gardeningknowhow.com/ornamental/flowers/roses/japanese-beetles-roses.htm