That's depressing. The last thing I read was that they had only migrated as far south and west as Kentucky. It appears that they are now in all counties of KY and I suppose that means they will soon be here too. I do not want
here. We have enough (bad) bugs!
When infestations of any insect are particularly bad I found only two things that can work.
One is to cover the plants you need to save with barrier material. One does not get to look at the plants but the material will allow light(70-75%) & water though it so the plants don't mind. When the worst is over, just remove the cover.
The other is to anticipate the problem and setup (plant) trap plants some good distance away and when the bugs think they are having their cake and eating it too, so to speak, kill them with poisons that one would not use on other plants or, if bad enough, pour kerosene over them and burn them. (do _NOT_ use gasoline - it is much too volatile).
Well, there is a third, which I have done: yank all the plants and toss them into a closed bin. Two years ago it was the cowpea curculio
on peas; this year the harlequin
I still have a few of the harlequin as I caught them a bit late but the trap plants and "Garden Dust" got most of them.
Actually I have to make a mix and spray today(now), in spite of the heat, because aphids
are so bad.
IOW, Jap beetles are going to have plenty of competition if|when they show here.
Harlequin are the worst - very hard to kill and apparently even harder to remove from the property! " If infestations are heavy and food becomes scarce, harlequin bugs will also feed on squash, corn, bean, asparagus, okra, and tomato
I have found that they also feed on chard and arugula
, which certainly covers everything, except peppers & edible|medicinal plants, I normally grow.
https://hgic.clemson.edu/factsheets/hgic2201.htm & https://www.ivyhall.district96.k12.il.us/4th/KKhp/1insects/harlequin.html