At first, I was just knocking them off into sudsy water early in the morning and/or late in the evening when they were inactive. I would leave them in the water a couple of days to make sure they were good and dead and then put them on the compost pile. However, I thought it might be better just to catch them in a jar and give them to my neighbor for his chickens which are coop bound. I began my battle on the 8th day of June, and it has continued unto this day. In one day, I might get over 400 or as few as 49, but the typical day was probably somewhere in the middle of that. I've given them to my neighbor for his chickens for 10 days, and I'm sure the chickens enjoyed the added protein.
One day I caught a couple of June bugs as well for the chickens. If you've heard the phrase, "like a chicken on a June bug," you can probably surmise that a chicken will readily eat a beetle. (I knew a guy that everyone called Junebug. I have no idea how he got his nickname.) The June bugs are considerably larger than the Japanese beetles.
I also caught another beetle one day--you can see it floating amongst the Japanese beetles in this shot. I'm not sure what it is. * (It is roughly the size of a June bug, but is tan whereas a June bug is a metallic green.)
My routine was to knock them off into the jug of sudsy water. The next day I would transfer them to a bucket to sit for a day. (I made the mistake one year to put them on the compost pile the very next day after I caught them, and I found some weren't completely dead. Of course, with giving them to the chickens, there isn't that issue to worry about. If they have become active in the jar, refrigerate it briefly to inactivate them so the chickens can get every last one.)
The last two weeks, the routine has been to knock them off into a jar and give the jar to my neighbor (or set the jar near his steps). He returns the jar by propping it in the Virginia creeper vine atop my fence.
As you can see, they've done quite a bit of damage to the Virginia creeper vine, but only minimal damage to the nearby muscadine vine.
Here's another shot of the Virginia creeper. It seems a majority of the leaves have at least some damage.
On the other hand, here is one skeletonized leaf among many healthy leaves on the grapevine.
Some green grapes are coming on. The last 2 years, they fell off prematurely, but again I hope for a harvest.
A fruit-bearing vine or tree can sustain some damage without hurting the fruit production. In my opinion, it's best not to worry about the plants being picture-perfect.
Milky spore can be sprayed on the lawn to control the beetles in their larval stage, but it's expensive. Knocking them off and feeding them to the chickens is cheap. If you have free range chickens, just go around and shake your bushes, trees, and vines very early in the morning, and the chickens will get them when they hit the ground.
The beetles will be active in the adult stage for just a little while longer. Then the eggs which have been laid in the ground will hatch and overwinter as grubs. The moles will feast on the grubs underground. Then next June the battle will commence again.
I think the tan beetle might be what is called a grapevine beetle, and some people call it a spotted June beetle, Pelidnota punctata.