A Rise in HLB Detections

Detections of Huanglongbing (HLB), the causal agent of the incurable citrus greening disease, have risen significantly in 2018 compared to the previous years. A reason for the rise in finds can be attributed to improved sampling and monitoring methods.  In 2018, the California Department of Food and Agriculture’s (CDFA) Citrus Pest and Disease Prevention Program (CPDPP) redoubled efforts to limit the spread of HLB and its vector. HLB is spread by a small pest called the Asian citrus psyllid (ACP) as it feeds on citrus tree leaves. The disease is fatal for citrus trees and has no cure. Once a tree is confirmed with the disease, the California Department of Food and Agriculture (CDFA) removes the infected tree from the property in order to protect neighboring citrus trees.

HLB was detected in 269 trees in 2017 and 699 trees in 2018, with a majority of these occurring in Los Angeles and Orange counties. The disease was first discovered in in Hacienda Heights, California, in 2012. The disease has not yet been detected in a California commercial grove, though most industry experts believe it’s just a matter of time.

One of the means of limiting the spread of HLB is implementing quarantines when ACP is discovered. ACP quarantines are already in place in 27 counties (including Santa Barbara County) in the state.  Information regarding quarantine zones and protocols is available through the CPDPP website. The quarantines throughout the state limit the transport of citrus across state and international lines, and between areas where the psyllid and disease have been found. Additionally, CDFA has agriculture crews canvassing the state to inspect backyard citrus trees for the Asian citrus psyllid and HLB.

Adult Asian Citrus Psyllid (ACP) feeding on citrus.  Photo-UCCE.