Subtropical Fruit Crops Research & Education
University of California
Subtropical Fruit Crops Research & Education

Posts Tagged: dogs

Dogs on The Trail of HLB

A team of dogs trained to identify Huanglongbing-infected citrus trees by scent has detected evidence of early HLB infection in commercial groves in Ventura County.

The canine visit was arranged on behalf of the ACP-HLB Task Force by Farm Bureau of Ventura County, which signed a contract with the commercial company that trains and manages the dog teams. Four dogs and two handlers from F1K9, along with the company's operations manager, departed from Florida on July 24 and arrived in Ventura on July 26. Grove scouting began July 29 and ended Aug. 1.

During that time, the team inspected approximately 3,500 trees on 20 ranches in three major citrus production areas: the Las Posas Valley, the Santa Clara River valley, and the Ojai Valley. The dogs alerted on 211 trees, indicating early HLB infection is present in all three areas.

In preparation for the scouting visit, we prioritized potential locations on the basis of four criteria:(1) the presence of "hot spots" where plant and/or ACP samples yielded inconclusive DNA test results during the California Department of Food and Agriculture's periodic HLB surveys; (2) proximity to major transportation arteries; (3) a long history of established Asian citrus psyllid populations; and (4) a low level of participation in ACP suppression efforts by both growers and homeowners.

We also sought volunteers who would allow their ranches to be scouted, agree to pay for the cost (about $4.50 per tree), and agree to remove suspect trees. We agreed to keep the specific locations confidential unless granted permission to share that information by the owner.

The ranches the dogs scouted included one west of Fillmore along Highway 126, one west of Santa Paula without highway frontage, eight at the east end of the Ojai Valley, one outside of Moorpark along Highway 23, one north of Somis without highway frontage, and nine along a 4-mile stretch of Highway 118 west of Somis.

The dogs alerted on a single tree at one of the eight ranches they scouted in the Ojai Valley. Dogs indicated early HLB infection in multiple trees at every other location they scouted.

Although more than 1,600 HLB-infected trees have been confirmed and removed in urban yards in Los Angeles, Orange and Riverside counties, the recent dog alerts here are the first evidence of widespread HLB infection in commercial citrus in California. It is also the first time this early detection technique (EDT) has been deployed for non-experimental purposes, as a tool for commercial growers to make decisions about tree removal to potentially eliminate sources of infection and halt or delay the epidemic's spread. (Up-to-date summaries of the HLB epidemic can be found here:

Because neither the U.S. Department of Agriculture nor the California Department of Food and Agriculture recognize dog alerts as direct proof of the presence of the causal agent of HLB, the canine alerts do not trigger regulatory action. This allows growers to remove suspect trees voluntarily without the complications and cost associated with quarantine requirements that would be triggered by confirmation through official DNA testing.

Despite their non-regulatory status, the dogs' ability to accurately identify early HLB infection in citrus trees has been scientifically demonstrated and validated. The four canines that traveled to Ventura County last month are part of a 19-dog group trained to detect HLB through a multi-year research and development program funded by the U.S. Department of Agriculture and overseen by Dr. Tim Gottwald at the USDA research station in Fort Pierce, Fla. Dr. Gottwald has presented updates on the project at the last four International Research Conferences on HLB, including the most recent one this year in Riverside, as well as at many other scientific gatherings. One of his presentations on the project is available to view online.

The dog's indication of early HLB infection in local commercial groves is a watershed moment in the history of Ventura County's citrus industry. We've long known this day would come, but that doesn't prevent the news from landing as a gut punch. The knowledge we are gaining through strategic deployment of the canine team, however, gives growers here a fighting chance to stem the epidemic's spread while there is still time to do so

And so far, the distribution pattern of dog-alert trees - in general, widely scattered along grove perimeters - suggests we may be catching the epidemic in its very early stages. If this proves to be the case countywide, prompt tree removal and a zero-tolerance policy toward the Asian citrus psyllid - meaning total commitment to the ACP-suppression treatment program - may buy us years of continued viability and profitability even in the face of this threat.

To that point, it is more critical than ever for ACP to be well-controlled: No psyllids means no spread of disease. Growers should continue to treat when asked to for the area-wide treatments. But in addition, Dr. Beth Grafton-Cardwell of UC Riverside now recommends that perimeters be scouted every two weeks, and if psyllid eggs or nymphs are found, that the orchard be treated immediately. These additional treatments, above and beyond the area-wide treatments, must be applied whenever psyllids are found, to keep ACP suppressed below detectable levels.

We are planning to bring the dogs back out for additional scouting as soon as it is feasible. We need to visit other areas that meet the risk-factor prioritization test, so we can establish a baseline picture of how HLB is distributed throughout the county. This will help guide our ACP-suppression and HLB-eradication strategy going forward.

Potential participants are welcome to contact Farm Bureau CEO John Krist for inclusion on the list of properties prioritized for future scouting, so long as they are willing to pay for the cost (currently estimated at about $4.50 per tree), and agree to remove suspect trees. The dogs' time is too valuable and their availability too limited to deploy them where the information they provide won't be acted upon. Ultimately, our intent is to have a team based here permanently, but that will take time and money. We're exploring ways to make it happen.

For a full report on the Ventura County scouting visit, including documents describing the scientific basis of the canine program, go to

dog survey
dog survey

Posted on Friday, August 30, 2019 at 6:08 AM
Tags: acp (86), citrus (338), dogs (4), hlb (71)

Citrus Canine Manager Postion Available

Interested Parties should email a resume to



JOB TITLE: CRB Canine Project Manager


CLASSIFICATION: Regular – 12 month, exempt, at-will or Independent Contractor

LOCATION: Riverside, CA or Remote

WORK HOURS: Typically Monday through Friday; frequent extended hours and weekends, travel subject to operational demands

SUMMARY: The Citrus Research Board Canine Project Manager provides important support to the CRB for follow-through and implementation of a strategic plan developed by citrus HLB diagnostic stakeholders to transition canines for use and commercialization in California. Problem-solving, communications, writing, priority setting, time management and business development skills are necessary.

The Citrus Research Program(a.k.a. Citrus Research Board) is a grower-funded and grower-directed program established in 1968 under the California Marketing Act as a mechanism for enabling the California citrus growers to sponsor and support needed scientific and technical research to further the goals of the California citrus industry. The program is administered by the Citrus Research Board, which is commonly referred to as the CRB.


  • Serve as the lead support staff for the implementation of the strategic plan described in the summary above.
  • Work as a liaison with the detector canine owners (USDA-APHIS), trainers (F1 K9), researchers and California citrus HLB diagnostic stakeholders (CRB, Citrus Pest & Disease Prevention Program/Committee, California Citrus Mutual and others) to communicate progress in implementation of the plan.
  • Serve as a member of the CRB staff, unless established and designated as an independent contractor.
  • Under the direction of the President and/or the Chief Research Scientist, write “white papers”, reports, concept documents and other canine detector-related documents.
  • Provide staff and organizational assistance to the HLB Detector Canine Transition Team. This involves working with representatives of the various stakeholder groups, researchers, government officials and others.
  • Draft transition team meeting notices and agendas. Prepare and submit minutes in a timely, correct and professional manner.
  • Provide vision, ownership, accountability and leadership for project management. Details include involvement in strategic planning, follow-through on the subsequent strategic plan, reporting to the CRB and other stakeholder groups, negotiating contract terms with vendors and commercialization of the canine detector teams.
  • Perform other duties as assigned by the Chief Research Scientist and/or the President.



  • Clear, effective written and oral communication.
  • Self-starter and can-do spirit with pride in the outcome of the final project.
  • Leadership, thoroughness, accuracy, objectivity and integrity.
  • Knowledge, experience and ability to relate the science of HLB detector canines to the citrus industry and the public in order to establish their credibility and gain confidence in them as an early detection technology.
  • Ethical conduct and the ability to exercise confidentiality.
  • Ability to create, organize and publish data.
  • Ability to meet deadlines and organizational goals.



B.A. or B.S. in a relevant science field is required. PhD preferred. Industry experience in science communication, entrepreneurial commercialization, and/or research project management may be substituted. Solid experience and knowledge of Microsoft Outlook, Word, DropBox, Office 365, PowerPoint and Excel is strongly advised. Must have legal authorization to work in the U. S.


  • Possession of a valid California Driver's License and clean driving record.
  • Frequent out-of-town, multi-day business trips will be necessary.
  • Preparing and delivering oral presentations and written progress reports.
  • Ability to work both independently and in group settings for problem-solving, coordination and collaboration.
  • Competent use of standard office equipment such as computers, scanners, database management software, telephones and photocopiers.
  • Lifting of boxes and other field materials weighing up to 35 pounds.
  • Ability to spend significant time in citrus orchards and training facilities, including the observation of canine detector teams during extended periods of heat and cold.



The Citrus Research Board is an equal employment opportunity employer without regard to race, color, national origin, gender, age, marital status, religion, disability, sexual orientation, pregnancy, or veteran status or other characteristics protected by the law.

dog sniffing
dog sniffing

Posted on Thursday, December 20, 2018 at 5:30 PM
Tags: acp (86), detection (2), dogs (4), early detection (1), hlb (71)

Avocado-Disease Dog Sniffers

Dogs can detect agricultural diseases early

Study shows dogs can sniff out laurel wilt-infected avocado trees well in advance

American Society for Horticultural Science

A study out of Florida International University evaluates the use of scent-discriminating canines for the detection of laurel wilt-affected wood from avocado trees. Julian Mendel, Kenneth G. Furton, and DeEtta Mills have ferreted out a possible solution to a serious issue in one corner of the horticultural industry, and then ascertained the extent to which this solution is effective.

The results of this study are presented in their article "An Evaluation of Scent-discriminating Canines for Rapid Response to Agricultural Diseases" published in the latest issue of HortTechnology.

Laurel wilt disease has resulted in the death of more than 300 million laurel trees in the United States alone. One affected plant is the commercially important avocado tree, the second-largest tree crop in Florida behind citrus. This disease has had a devastating effect on the industry in South Florida in past harvest seasons, and two larger avocado industries in Mexico and California are naturally worried that this disease, if it hits their crops, could spread fast enough to destroy their seasons.

Once affected by laurel wilt disease, trees succumb soon after infection. Once external symptoms are evident, this disease is very difficult to control and contain as the pathogen can spread to adjacent trees via root grafting. Until now, there has been no viable, cost-effective method of early diagnosis and treatment.

Laurel wilt is the consequence of an invasive species--the redbay ambrosia beetle--originally from Asia, which was inadvertently introduced into the United States in untreated wooden packing material.

But as with so many ailments, early detection can be instrumental in deterring a widespread infection. The use of scent-discriminating dogs has shown to offer the avocado industry legitimate signs of hope in their fight against the spread of such a profit-crusher throughout their groves.

Three dogs were trained and studied for their ability to detect the early presence of laurel wilt by scent. At present, canines are extensively used in law enforcement and forensics in the location of missing persons, explosives, drugs, weapons, and ammunition. More directly applicable, dogs have demonstrated the ability to detect invasive species of spotted knapweed, brown tree snakes, desert tortoises, and various cancers.

The highly sensitive canine olfactory system is capable of detecting odor concentrations at exceedingly minute 1 to 2 parts per trillion. The authors believe it likely, with properly directed training, that these dogs could use their natural talents to service the protective needs of the potentially ailing avocado industry.

During the course of the study, 229 trials were performed, and only 12 of those yielded false alerts. It was observed that dogs are indeed capable of high levels of relevant performance, even in harsh weather conditions such as high heat and humidity. The study provided proof that dogs can detect agricultural diseases such as laurel wilt and can be a powerful management tool if the disease is caught in its earliest stages.

About the valuable service provided by these dogs, Mills adds, "It is the best 'technology' so far that can detect a diseased tree before external symptoms are visible. The old saying that 'dogs are man's best friend' reaches far beyond a personal bond with their handler and trainer. It is depicted in their excitement every day as they deploy to the groves. Man's best friend may even help save an industry."

The complete article is available on the ASHS HortTechnology electronic journal web site:, doi: 10.21273/HORTTECH03794-17. Or you may contact DeEtta Mills of Florida International University at or call her at (305) 348-7410.

Also a great article on dog-sniffing bee hives for foul brood.  Go DOGS!


Cobra, a 3-year-old Belgian Malinois, is trained to detect laurel wilt-diseased trees before the visible symptoms are seen. She and two other Dutch Shepherd canines detect asymptomatic, but infected trees. Once a diseased tree is identified, these "agri-dogs" will sit, indicating a positive alert.

dog sniffer
dog sniffer

Posted on Friday, June 29, 2018 at 6:35 AM
Tags: avocado (289), dogs (4), laurel wilt disease (9), LWD (2)

Dogs to the Rescue

On a recent trip to Florida we saw a dog in action locating avocado trees that had been attacked by the Redbay ambrosia beetle which carries the fungus Raffalea lauricola which is a similar pest/disease complex that is found in California with the Polyphagous/Kuroshio Shot Hole Borer and Fusarium Euwallacea that leads to Fusasrium Wilt in avocado. The fungus gives off a certain odor that the dog is trained to smell and along with the human trainer goes around the orchard to identify infected trees.  The trees can then be removed so that they don't act as a reservoir of infection that can be spread to other trees by the beetle.  The dog seemed to work pretty fast.  Depending on the acreage covered, the handler says they charge $150 per acre to find diseased trees.  This can happen before more advanced symptoms show up that humans can see.  This technology could be used in identifying other tree diseases, such as Huanglongbing, citrus canker and Phytophthora,  along with others.


Dog has found a laurel wilt infected tree that will soon be removed. (Tim Spann).

dog identifying lw tree
dog identifying lw tree

Posted on Monday, November 21, 2016 at 8:22 AM
Webmaster Email: