On a global scale, one of the most important issues within citrus is the disease known as Huanglongbing (HLB), caused by several species of bacteria (Candidatus Liberibacter spp.) and vectored by phyllids, primarily the Asian citrus psyllid (ACP) (Diaphorina citri). In the U.S.A., the disease has devastated citrus production in Florida and is now threatening other citrus growing regions within the network. In April of this year, NCPN-C chair Georgios Vidalakis provided an update on the HLB situation at the 20th International Organization of Citrus Virologists Conference in Chongqing, China. The vector was first discovered in San Diego, CA in 2008 and has spread as far North as San Mateo County. This resulted in wide spread ACP quarantine efforts and ACP ‘task forces' to implement control measures in California. The first HLB positive tree was identified in the Los Angeles area of Hacienda Heights in 2012. The second HLB positive tree was not found until 2015 approximately 15 miles northwest of the first positive tree; now 12 additional trees have been identified within this same area. All trees have been removed and destroyed. Collaborative efforts continue in research and ACP/HLB testing within industry, state, and federal entities to combat this threat.
Recent NCPN-affiliated publications on citrus crop viruses:
da Graça, J., Douhan, G., Halbert, S., Keremane, M., Lee, R., Vidalakis, G., Zhao, H. 2016. Huanglongbing: An overview of a complex pathosystem ravaging the world's citrus. IJPB 58:373-387 http://dx.doi.org/10.1111/jipb.12437