The citrus disease known as “Huanlongbing” has been raging for seven years, killing millions of orange and grapefruit trees across Florida. Now it’s been detected in California. - 

Jeremy Hobson: Here in Southern California, there are concerns about something called "citrus greening." It's a disease that turns fruits into small bitter lumps and slowly kills every tree it infects. "Citrus greening" has ravaged orange crops in Florida for years, and now, it appears to have struck California.

Sanden Totten of station KPCC in Pasadena reports.

Sanden Totten: The first victim was a lemon pomelo tree in someone's front yard. The disease probably came from an imported graft. But it's spread by tiny flies called Asian Citrus Psyllids.

Tina Galindo: Did you check this tree?

Tina Galindo works with the California Department of Food and Agriculture. She's leafing through a lime tree hunting for those bugs to test for the disease.

Galindo: You can see how small this insect is that we are looking for. It's just about the size of a flea.

The flies are so tiny, one gust of wind could blow them clear across town -- spreading the infection.

Mark Hoddle: It's a death sentence for the tree. There's no cure. You can't give them antibiotics.

That's Mark Hoddle, entomologist at the University of California in Riverside.

Hoddle: So once it's infected it's just a matter of time before it goes into decline and eventually dies.

So far, that lone lemon tree is the only known case in California. If no other outbreaks pop up, that'll be sweet news for the sour fruit.

In Los Angeles, I'm Sanden Totten for Marketplace.

Follow Sanden Totten  at @sandentotten