ACCURATE HUANGLONGBING (HLB) DIAGNOSIS

The United States is the world's second-largest orange producer after Brazil. Together, the two countries account for over half of world production. US citrus production in 2009-10 was 10.9 million tons, with a packinghouse-door value of $2.88 billion. In the United States, citrus orchards are plagued by two devastating invasive diseases introduced in the past two decades. The first, citrus canker, is caused by Xanthomonas axonopodis pv. citri, a bacteria associated with citrus leafminer (CLM), Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae) damage. The damage caused by CLM larvae opens the door for canker infection. The second disease, Huanglongbing (HLB) or citrus greening disease, is caused by Candidatus Liberibacter spp., a bacteria vectored by Diaphorina citri, the Asian citrus psyllid (ACP). Since 1995, (the third cycle of detection) citrus canker has been detected in 24 Florida counties, and along with the first detection of HLB infected citrus trees in 2005, has triggered a concerted effort to detect and remove infected trees, which has now become a monumental task. The yearly rate of tree removal from FL groves reached over 1 million HLB infected citrus trees in 2009. The HLB pathogen invariably follows the vector, with trees showing signs of the disease in approximately one to three years after infection. During these years of incubation, the tree remains in the grove as a source of inoculum that contaminates, via the ACP vector, other trees. There is an immediate need to have a highly sensitive, hand-held device that gives growers the diagnosis immediately in the field, in front of the tree that might be infected, so that the grower can make an educated decision regarding tree removal. Successful completion of this project will provide citrus growers with a valuable tool for managing these two terrifying diseases, and enhance the diagnosis of diseased trees, even in the beginning stages of infection.

Successful completion of this project will provide citrus growers with a valuable tool for managing these two terrifying diseases, and enhance the diagnosis of diseased trees, even in the beginning stages of infection. If successful, there is a high potential that this pathogen sensory system could be used throughout the agricultural industry and beyond, including public health and those orchards that cannot or do not use conventional pesticides.