LOS ANGELES TIMES - Growing citrus is a dicey business these days in Southern California, and not at all recommended if you live within a two-mile radius of a tree infected with Huanglongbing disease — a.k.a. HLB or citrus greening disease. However, if you live outside a “red zone” and you’re willing to actively fight the disease, then yes, it’s still possible to grow limes for your margaritas.
But you’ll have to be ruthlessly proactive by declaring brutal warfare on the ants in your yard while embracing a tiny parasitoid wasp that eats its living prey from the inside out.
HLB is a bacterial disease spread by the tiny Asian citrus psyllid that loves to suck the sap from tender new “flush” growth on citrus and then lay its eggs. If the psyllid sups on a tree with HLB, it spreads the disease to every other tree it visits, and once infected, there is no cure.
The University of California’s department of Agriculture and Natural Resources has created an interactive map that identifies hot zones of infection: in Southern California they’re mostly in the four-corners area where Los Angeles, Orange, Riverside and San Bernardino counties meet. Enter your address and it shows how close your home is to those infection areas.
Find out if your area is affected with UC ANR's interactive HLB proximity map:
Check your citrus trees for Asian citrus psyllid: