How trained dogs are successfully helping detect diseases in citrus trees

Contributed by Shelby Watts | Junior | Agricultural Science

Detector dog named Szaboles sniffing out bacteria. Photo from Smithsonian Magazine.

Dogs have been labeled man's best friend since the dawn of time. From K-9 units to herding dogs or even the common household companion, dogs have been a positive influence for mankind. Now, they are serving a new purpose within the agriculture industry as tools of detection for huanglongbing— commonly known as citrus greening. 

Citrus greening is a disease caused by bacteria often associated with various varieties of psyllid insects. 

Symptoms of this disease resemble that of nutrient deficiencies but, the most distinctive and problematic of the symptoms is the green appearance and stunted growth of citrus fruits. This disease can also produce an “off-flavor” in infected fruits. 

Photo provided by USDA.

Various detection methods have been attempted but none have been as successful as the use of specially trained dogs to detect a signature scent given off by the disease-causing pathogen. 

With a 99% accuracy these dogs can detect the pathogen’s presence before symptoms of the disease even occur, optimizing control of spread and minimization of wasting resources on infected trees. 

Currently, the only USDA approved detection of this disease is through a DNA analysis that still can only detect about 66% of affected trees a year after contamination. While trees can be asymptomatic for a time period of months to even years, the trained canines can detect infection within that window of time. 

About 20 of these dogs have been trained for this task and have been working vigorously in all areas viable for citrus production. 

Through various trials across the country, dogs trained in pathogen scent detection have proven to be somewhere in the 90s on percentage of accuracy. Just like many of their counterparts sniffing out contraband in airports, these canines have proven useful in sniffing out another threat to the agriculture and food supply industry. 

The future is looking bright for the partnership between canines and citrus.