U.S. flagAn official website of the United States government
                    Here's how you know **Official websites use .gov**
                            
                            A **.gov** website belongs to an official government organization in the United States.
 **Secure .gov websites use HTTPS**
                            
                            A **lock** (                            
                              A locked padlock                                                      
                            
                            ) or **https://** means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.


Menu Agricultural Research Service
						
                    U.S. DEPARTMENT OF AGRICULTURE
 close



Research
                Research Home
                            National Programs
                            Research Projects
                            Scientific Manuscripts
                            International Engagement
                            Scientific Software/Models
                            Databases and Datasets
                            Office of Scientific Quality Review
            Media
                News & Features
                            Multimedia
                            Briefing Room
                            Down on the Farm
                            Press Room
                            Science in Your Shopping Cart
                            Scientific Discoveries
                            Tellus
                            Under the Microscope
            About ARS
                About ARS Home
                            Staff Directory
                            Labs and Research Centers (Map)
                            Headquarter Offices
                            Organizational Chart
                            Employee Services (REE Employees Only)
                            Office of Outreach, Diversity, and Equal Opportunity
            Work With Us
                Work With Us Home
                            ARS Vacancies at USAJOBS
                            Careers at ARS Information
                            Scientific Collaborations
                            Extramural Agreements
                            1890 Faculty Research Sabbatical ProgramSearch small
                    Search
            
            ARS Home
                                About ARS
                                Contact Us




ARS Home News & Events News Articles Research News 2020





- ARS@Work
- Blog
- Down on the Farm
- Image Gallery
- News Archive
- Podcasts
- Press Room
- Science in Your Shopping Cart
- Scientific Discoveries
- Tellus
- Under the Microscope
- YouTube Channel

Watch a video
 Trained Dogs Are the Most Efficient Way to Hunt Citrus Industry's Biggest Threat By Kim Kaplan February 3, 2020 **FORT PIERCE, Florida, Feb. 3, 2020—**Dogs specially trained by Agricultural Research Service (ARS) scientists have proven to be the most efficient way to detect huanglongbing—also known as citrus greening—according to a paper just published in the *Proceedings of the National Academy of Sciences*. Currently, the only solid hope of curtailing the spread of citrus greening is to eliminate trees with the disease as quickly as possible to prevent further spread. Early detection of the citrus greening pathogen is crucial because trees can be infected and act as a source to spread the disease months or years before showing symptoms that are detectable by the naked eye. ARS plant epidemiologist Timothy R. Gottwald with the U.S. Horticultural Research Laboratory in Fort Pierce, Florida, discovered that dogs can be trained to sniff out the presence of *Candidatus Liberibacter asiaticus,* the bacteria that causes citrus greening, with greater than 99 percent accuracy. "We found that, once trained, these dogs were able to identify infected trees within two weeks of the trees being inoculated," Gottwald said. "The dogs also were able to distinguish the citrus greening pathogen from a variety of other citrus bacterial, viral, fungal, and spiroplasma pathogens, including closely related Liberibacter species. During testing, the citrus greening detector dogs had total of 4 to 15 false negatives and false positives on 950 to 1,000 trees per dog. Occasionally, the dogs alerted on clean trees that were in the same spot where an inoculated tree had been placed in previous tests due to residual scent. In contrast, the only currently USDA-approved method for confirming the presence of the citrus greening pathogen—a DNA-based assay called a polymerase chain reaction (PCR) test detected less than 3 percent of infections at 2 months, 16 of 30 inoculated trees at 16 months, and 20 out of 30 in 17 months. PCR tests also require considerable time, financial and human resources for sampling, processing and laboratory work. They are very expensive to use as a general surveillance tool. The training is similar to that of explosives sniffing dogs, in which the dogs are taught to recognize a particular odor and to sit down next to the source once found. The dogs are rewarded with play time with a toy.  However training is more extensive and specific because the dogs are trained to detect a bacteria infecting a plant, and the two cannot be separated. So far, Gottwald's program has trained 19 dogs obtained from European breeders of detection canines because of their keen abilities and drive. "When we ran epidemiological models, we found canine detection combined with infected tree removal would allow the citrus industry to remain economically sustainable over a 10-year period, compared to using molecular assays or visual inspection combined with tree removal, which failed to suppress the spread of infection," Gottwald explained. Citrus green sniffing dogs have been deployed for 9 months in California and northern Florida. In the past decade, huanglongbing has caused more than 70 percent decline in the production of oranges for juice and the fresh fruit market in Florida and threatens other states, making it the largest economic threat to the $3.35 billion U.S. citrus industry. It was first found in the United States in 2005, citrus greening has spread to Florida, Texas, California, Georgia, and Louisiana. *The Agricultural Research Service is the U.S. Department of Agriculture's chief scientific in-house research agency. Daily, ARS focuses on solutions to agricultural problems affecting America. Each dollar invested in agricultural research results in $20 of economic impact.*


Return to top


Research
                            Media
                            About ARS
                            Work With Us


Connect with ARS Sign up


ARS Home
                            USDA.gov
                            Plain Writing
                            Policies & Links
                            Civil Rights Statements
                            FOIA
                            Accessibility Statement
                            Privacy Policy
                            Non-Discrimination Statement
                            Quality of Information
                            USA.gov
                            WhiteHouse.gov