Help stop the striped cucumber beetles on their lawless march of death!

This year I planted 8 rows of popcorn, primarily so that my kids could see the seeds germinate, grow into plants, then help harvest the popcorn. (and pop it, of course) We live in the city, so it is fun being able to look 5 feet out from the kitchen window and see those tall stalks of corn right there.
Lately, however, striped cucumber beetles have started stripping the leaves. I have 6 short rows, and about 26 plants total. Twice a day, after breakfast and supper, I go out and squash as many as I find. Usually that comes to more than two dozen a day, or about one per plant. They seem to be eating the leaves from the underside. It also seems like they congregate and strip primarily one leaf, then go on to the next, almost as if they are leaving a chemical marker letting other beetles know the best place to eat.
I've tried applying thiodan a couple of times, with a stronger dose the second time. I've also tried diazinon. Neither seemed to have any effect on the beetles at all.
Obviously, my squishing is causing something - I've killed 250 of them so far. Unfortunately, since I have the only corn plants for probably half a mile, they seem unusually drawn to my back yard.
Anyone have any idea what I can do to save my corn plants, and get an actual crop? The squirrels didn't attack this year, and I was just starting to think I might actually get some popcorn out of it. Thanks!
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