image: Detector canine 'Boby' scouting citrus orchard for the bacterial pathogen Candidatus Liberibacter asiaticus, which causes citrus huanglongbing. view more
Credit: Image courtesy of Gavin Poole
A study finds that dogs can be used to detect a major crop pathogen and to distinguish between multiple crop pathogens. Huanglongbing, a severe infectious disease of citrus trees, is caused by the bacterium Candidatus Liberibacter asiaticus (CLas), which can devastate citrus agricultural production. Neither visual inspection nor molecular assays can detect infection sufficiently early to mount an effective response; the latter are also too expensive and time-consuming to deploy on a large scale. Timothy Gottwald and colleagues trained dogs to distinguish CLas-infected from noninfected trees via smell and assessed the dogs' performance in a model orchard. The dogs detected infections with greater than 99% accuracy. In a longitudinal study, the dogs identified all infected trees within 30 days of inoculation, whereas detection by a molecular assay took months to years. Dogs were also able to accurately distinguish CLas from a variety of citrus pathogens in an international repository, and could detect CLas in noncitrus plant and insect hosts as well as in liquid culture. The authors used epidemiological models to simulate the effects of disease control based on canine detection versus commonly used detection methods. Canine detection combined with infected tree removal was economically sustainable over a 10-year period, whereas molecular assays or visual inspection combined with tree removal largely failed to suppress the spread of infection. According to the authors, the study suggests that dogs can be cost-effectively used to screen for CLas infection in real time.
Article #19-14296: "Canine olfactory detection of a vectored phytobacterial pathogen, Liberibacter asiaticus, and integration with disease control, and integrated disease control," by Timothy R. Gottwald et al.
MEDIA CONTACT: Timothy R. Gottwald, United States Horticultural Research Laboratory, United States Department of Agriculture, Fort Pierce, FL; tel: 772-462-5883, 772-216-1491; e-mail: Tim.Gottwald@usda.gov
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Journal
Proceedings of the National Academy of Sciences