Didn't know about the parasite.

Got off my lazy butt (ok, still on my lazy butt, but started typing and researching), and found it. I think it's called sweet orange scab, and is a fungus rather than a parasite.

My recollections of learning about it are from long ago road trips from So Cal to visit extended family in AZ, and one trip in particular where we got to eat up all of the oranges we brought with us at the border inspection station (could have thrown them out, but why waste perfectly good food.) The inspector showed us what he was looking for and did a great job of quickly explaining the issue to a car full of curious kids. (All of my siblings and I enjoyed learning, but I was the only one who would sit down and read the Encyclopedia just for the fun of learning new things. Probably still explains my somewhat overuse of the internet today. There's so much to learn!)

Apparently since then, it has spread to AZ. That's shifted priorities from keeping it out to looking for and treating local outbreaks in the state.

--Peter