Skip to main content
ARS Home » Southeast Area » Fort Pierce, Florida » U.S. Horticultural Research Laboratory » Subtropical Plant Pathology Research » Research » Publications at this Location » Publication #335742

Title: Use of HLB detection canines in real world settings

item Gottwald, Timothy
item Poole, Gavin
item Taylor, Earl
item Hartung, John
item Hall, David
item BARTELS, DAVID - Animal And Plant Health Inspection Service (APHIS)
item McCollum, Thomas
item Hilf, Mark
item LUO, WEIQI - North Carolina State University
item LOUWES, FRANK - North Carolina State University
item Polek, Marylou
item VIDALAKIS, GEORGIOS - University Of California
item MAUK, PEGGY - University Of California

Submitted to: Journal of Citrus Pathology
Publication Type: Abstract Only
Publication Acceptance Date: 12/20/2016
Publication Date: 5/18/2017
Citation: Gottwald, T.R., Poole, G.H., Taylor, E.L., Hartung, J.S., Hall, D.G., Bartels, D., McCollum, T.G., Hilf, M.E., Luo, W., Louwes, F., Polek, M., Vidalakis, G., Mauk, P. 2017. Use of HLB detection canines in real world settings. Journal of Citrus Pathology. 4(1):16-45.

Interpretive Summary: Canines were tested against infections within different cultivars, roots, infections from both grafting and psyllids. In addition, dogs were tested against several different citrus diseases and isolates of HLB from around the world, as well as African and American forms of HLB). In all trials, the dogs had no problems identifying the HLB infected plants with a high degree of accuracy, regardless of species or isolate.

Technical Abstract: Using canines to detect HLB in citrus has shown extreme promise in the research environment. Tests on different aged infections, different cultivars, roots, and infections from both grafting and psyllids have all shown the dogs' abilities to detect and differentiate an HLB infected tree from clean trees at accuracies exceeding 99%. The next logical step is the introduction of the canines to “real world” environments, i.e., commercial citrus plantings and residential or “dooryard” trees to determine if detection accuracy continued. The dogs were introduced to a young grove in Florida first, and trained over the course of several months. However, due to the high incidence of infection in Florida, finding a suitable low disease incidence training area for dogs in a mature grove is almost impossible. The dogs were therefore taken to other states, especially Texas, for training and testing. This also allowed the dogs to work in different environments, different grove management practices, and different citrus species. Another aspect of early canine detection is the use of the dogs in residential environments. Again, using other states for a test bed, the dogs were run through various types of residential areas, including residential neighborhoods, mobile home parks, and even a Buddhist monastery. The dogs showed the adaptability to successfully work in these exceedingly diverse and sometimes environmentally hostile environments. Over the past year, the dogs have alerted to trees in four counties in California, including a recent sampling of the University of California Riverside Citrus Research Center. Specificity (in statistical terms the true negative rate) includes the ability of dogs to accurately discriminate between Candidatus Liberibacter asiaticus (CLas) infections and infections by other pathogens or extraneous scent profiles. To accomplish this, a group of the dogs was taken to Beltsville, Maryland and tested against trees held in the international pathogen collection composed of a number of different viral and bacterial citrus pathogen accessions from around the world. The canines consistently differentiated CLas-infected trees and did not alert on trees infected with other pathogens. One unique finding was that dogs trained on CLas were also intrinsically capable of detecting Liberibacter africancus (CLaf) and Liberibacter americanus (CLam) infected trees as well, without additional sensitization or training.