Another Beautiful Imported Pest
From the Orange County Natural History site: "An agricultural pest originating in the southeastern United States and arriving in Orange County about 1990. It feeds on at least 73 species of plants including sunflower, hollyhock, okra, cotton, corn, cowpeas, oak, ash, silktree, crapemyrtle, and peach, and is a vector of several plant diseases including phony peach disease, Pierce's disease of grape and Oleander leaf scorch."
I wonder if phony peach disease only attacks phony peaches, or whether it really isn't a disease at all.
Looks a lot like your average hopper (it's also a Cicadellidae) but it's big--about a centimeter long.