When the American citrus industry, worth a juicy $3.35 billion in Florida and California, faced a tough adversary in the form of the devastating Citrus Greening disease, researchers had to think outside the crate. Although the Citrus Greening disease does not harm humans or animals, it is fatal for citrus crops and once a tree is infected, there is no cure available. 

Testing for the bacterium that causes Citrus Greening disease poses a significant challenge because the bacterium is not uniformly distributed throughout the entire plant. Traditional testing methods, which involve taking a sample from the tree, are prone to producing false negatives, putting citrus crops at risk.  

In response, researchers at the USDA-ARS came up with an innovative solution - using Citrus Greening detector dogs and their incredible sense of smell to detect the bacterium that causes the disease in citrus trees. These clever canines can screen an entire tree and sniff out the presence of the Citrus Greening bacterium with 99% accuracy in just two seconds. 

The USDA-ARS collaborated with F1K9, now known as BIO Detection K9 (BDK9), to refine and expand upon the training techniques for canine pathogen detection. Since the commercialization of the USDA-ARS technology for citrus, canines have also been trained to detect the pathogens that cause other plant diseases such as citrus canker, plum pox, viral watermelon vine decline, and even fungal diseases like Botrytis. The technology also allowed BDK9 to develop a highly successful COVID detector canine program. 

According to the Food and Agriculture Organization of the United Nations, global plant disease costs the agriculture industry upwards of $220 billion. The potential of pathogen detector canines is vast, highlighting the versatility and usefulness of these four-legged friends.