Dogs trained to sniff out knotweed on building sites

A new start-up company has trained dogs to be able to sniff out Japanese knotweed on construction sites up to 40 times faster than it takes humans to detect it.

Helga Heylen, who founded the company in Ireland in January 2018, told Global Construction Review that just one of her dogs can survey a site 40 times faster than a human team. She also said the dogs have far higher accuracy since their powerful noses can detect even rhizomes that have not yet broken the surface of the soil. Wearing GPS-equipped vests, the dogs scour a site and sit down if they detect knotweet, staring at the spot.

Among the world’s most invasive species, Reynoutria japonica can grow at a rate of 10cm a day, and its hunger for water and light is so strong that it will push through cracks in masonry, concrete, asphalt and timber to get at them, undermining the structural integrity of walls, pipes and paved surfaces.

It is also highly insidious. One tiny fragment of its rhizome the size of a fingernail can lay dormant in soil for up to 20 years before spawning an entire new colony.

Working 40 times faster than humans, dogs can even detect rhizomes underground (CDI)

The alarm it generates was highlighted in Ireland last year when planning permission was refused for a facility in Ballyhaunis, County Mayo, intended to treat soil infected with knotweed.

The company planning the facility, to be sited in a disused quarry and said to be the first of its kind in Europe, could not provide the council with a cast-iron guarantee that it would not spread.

“Even when a site is excavated for knotweed, loose bits stuck on people’s boots or in vehicle tyre treads can spread it to a new place,” said Heylen, formerly a psychologist, business advisor and dog-lover who got the idea of setting up Conservation Dogs Ireland (CDI) after encountering medical detection dogs that can identify conditions in people, from anxiety and epilepsy to cancer.

She currently has three dogs, one pure-bred Labrador and two, rescued, Labrador-Beagle crosses.

“What five surveyors would cover in eight hours, one dog does in just one hour, with far superior results and accuracy,” Heylen added.

Helga Heylen, founder of Conservation Dogs Ireland, addressed the UK’s Property Care Association conference in 2018 (CDI)