Thanks to dogs that detect infected potatoes tubers and plant material, farmers can know now if their crops have a disease even before they see symptoms on the field.
Andrea Parish has trained three dogs to detect Potato virus Y (PVY) and Bacterial Ring Rot (BRR). PVY is a virus that causes yield losses and tuber quality defects in commercial potato crops; BRR is one of the most feared diseases of the potato industry, particularly for seed producers.
According to the Idaho State Journal, Parish, proprietor and creator of Nose Knows Scouting, has worked with her dogs in potato storage and fields from Washington to Maine since establishing her business in 2019. Her client list includes state certification programs and many eastern Idaho seed potato producers.
Most of his customers want to identify PVY on their farms. To achieve this, Parish’s dogs scour the vent tubes of their potato storage warehouses and sniff into their holes for infected tubers. Or the customers send her a sample from the pile for corresponding analysis. Another strategy used by Parish is to let the dogs scan the fields with volunteer potatoes and locate infected plants that could share PVY with new crops.
Other clients want to identify BRR in their equipment. In this case, unlike samples that can cover 1%, dogs go through equipment, storage, trucks, and bins to determine if the disease is present.
Parish’s dogs never touch the inventory, so there is no food safety issue.
But what makes these dogs unique? What makes his world odoriferous and not visual, like to humans? How do their noses differ, and what do their brains do?
Humans have long been using dogs as chemical sensors thanks to their skill to detect and locate a wide range of organic and inorganic odours. Today dogs can identify explosives, drugs, persons and cadavers, game animals, chemical accelerants, pollutants, toxins, and several types of cancer.
Unlike molecular and biochemical assays that need a sample from the host or environment, dogs can detect and localize odours non-destructive. So they can explore vast areas without sample collection or laboratory processing.
As reported by a Nova article, dogs’ sense of smell is 10,000 to 100,000 times as sensitive as humans’. If it makes a comparison with vision, what humans see a third of a mile away, a dog could see more than 3,000 miles away and still see as well.
In other words, dogs can catch some odours in parts per trillion. That means; a human might notice if tea has had a teaspoon of sugar added to it, but a dog could detect a teaspoon of sugar in a million gallons of water.
So what do dogs have that humans don’t? For starters, they have up to 300 million olfactory receptors in their noses; humans have about six million. And the part of the brain devoted to analyzing odours is about 40 times larger.
A small nasal cavity region keeps the human sense of smell, where inspired air enters and exits with exhaled air. In dogs, the process is different. Most of the inspired air goes to the lungs, but a small part moves to an area of the nose dedicated to smell. There, bone structures called turbinates filter the air carrying odours, depending on their different chemical properties, and send them to the brain as electrical signals for analysis.
Parish’s dogs are not unique; there are many examples today. The following are three experiences of the dogs' capabilities:
- Asian longhorn beetle, Anoplophora glabripennis, attacks maple and other tree species such as poplar, birch, willow, and elm. Usually, its surveillance depends on visual inspection, but researchers have trained dogs since 2009 to detect this insect as a complementary method. Some experiments provide data illustrating the feasibility of dog detection as a method in monitoring and surveying it.
- Laurel wilt disease, provoked by Raffaelea lauricola, has caused the death of more than 300 million laurel trees (Lauraceae) in the United States. One such tree is avocado (Persea americana), the second-largest tree crop in Florida. A recent study has indicated that dogs could detect laurel wilt–affected wood and the laurel wilt pathogen.
- Candidatus Liberibacter asiaticus is the causative agent of Huanglongbing (HLB), also known as citrus greening disease. Its early detection is the key to mitigating its destructive effects; however, a human visual check is not as sensitive to detect infections, and molecular assays are expensive. A research article indicated that dogs were more effective and cheap than early detection methods to disease control.
Qualified detection dogs that can find a particular invasive pest or disease on the field are becoming a more and more critical game-changer for global plant protection.
In the meantime, Andrea Parish has initiated a nonprofit foundation to raise funds supporting scientific research to confirm her idea. The University of Idaho and North Dakota State University are also publishing Parish’s training logs to supply data to the industry.
About the author
Jorge Luis Alonso G. is a writer specializing in potato cultivation who writes marketing content for ag-tech companies. He has lived with his family in Canada since 2018.