Here's a nice little summary of the predicament California citrus finds itself in now - by David Karp by way of the LA Times.

California farmers and scientists race to combat a citrus disease infecting trees

Mar 29, 2019 | 8:25 a.m. | Riverside

https://www.latimes.com/food/la-fo-citrus-greening-20190329-story.html

The world's most insidious citrus disease invaded Florida in 2005, wreaking havoc on its iconic groves with stunning speed. After just a decade, virtually every citrus tree in the state was dying or infected.

Then in 2012, the disease — Huanglongbing, commonly known as citrus greening — was discovered in California. It showed up first in a Hacienda Heights backyard, on a pummelo branch derived from budwood that had been smuggled from China, where the disease is epidemic.

The next infected tree wasn't found until 2015, and for two years after that only 81 more turned up. In mid-2017, however, a new sampling method and improved detection technology led to the discovery of far more HLB-positive trees in California: 1,135 as of March 11.

Now researchers and farmers are racing to fend off the disease. This month, more than 500 scientists from around the world gathered in Riverside at the sixth International Research Conference on Huanglongbing, meeting in California for the first time. Their findings show that although the disease is spreading rapidly in the Southland and no breakthrough is imminent, a host of new detection methods and strategies could help California avert the kind of disaster that destroyed almost three quarters of Florida's citrus production.

Huanglongbing originated in Asia a century or more ago. It is caused by a bacterium, Candidatus Liberibacter asiaticus, transmitted by a tiny insect, the Asian citrus psyllid, which feeds on young citrus leaves. HLB clogs citrus trees' phloem, a vascular tissue that transports sugar from the leaves; this causes the most symptomatic fruit to become small and bitter, and eventually makes trees unproductive or kills them.

Until now California has avoided painful losses from HLB, but that may be changing.

REad On: https://www.latimes.com/food/la-fo-citrus-greening-20190329-story.html

Photo: Deformed HLB fruit