Orthene works, Pyrethrum will knock them down, but not get rid of them. DON"T TOUCH them. Remember that nasty blister I got last year? (from sitting on one) The leg joints contain a chemical called cantharidin which causes blisters when you get it on your skin. Wear long sleeves and long pants if you are going to be close to them.
The adults of this beetle are plant eaters but the larva parasitize grasshopper eggs.
Cala, I'm not sure if I'm supposed to get rid of them or not now. They destroyed my tomatoes. Then my sweet autumn clematis. Then I found them on my St Vincents vine, and then this evening they were covering my pink cestrum. We got out the ant spray, it's the only thing they reacted to. But if the larvae are good, then did I cause myself a problem with grasshoppers???? Mine is 99% flowers, what would you have done, killed as many as possible or leave them alone????
TiG, they've probably already laid their eggs, so the larvae will still take care of some grasshoppers. The book recommends killing the adults, they are a crop pest. They can strip your plants. They almost killed my Japanese anemones. I vote to spray them!!