Plant ecologist Fiona Thomson, a hunter of rare plants, started the project after hearing about an Australian sniffer dog hunt for koalas.
At about the same time Southlander John Taylor started using his border collie Rustie to find noxious velvetleaf.
Until now Thomson and biosecurity officials had only trained dogs in lab conditions to detect needle grass leaf.
Needle grass was found in parts of Canterbury, Marlborough and Hawke’s Bay.
Dogs were heading to an affected area in Marlborough for a field test to find real plants.
Thomson said needle grass would be a good test for the dogs because it was a grass within grass and didn’t have a strong smell, unlike velvetleaf.
“Chilean needle grass is one of the hardest weeds to do.”
The real plants in the field scenario would test dogs’ detection skills before needle grass seeded, giving farmers the best shot at control with sprays like Taskforce.
Checks before seeding would also prevent dogs being injured by the notoriously sharp seeds, which were known for twisting into sheep pelts and muscle.
Trainer Geoff Bowers said dogs could remember up to three million smells and it took only about an hour to impregnate their senses so they could indicate for a new one.
They could detect to 99% accuracy so the hardest part was training the handler so they didn’t give false indications, he said.
“There’s absolutely no limit, myrtle rust … no limit.”
Working with Thomson and biosecurity officials, Bowers would soon start training dogs to find velvetleaf and about 15 other rogue plants.
Bowers, owner of the Kuri Dog Training Centre in Canterbury, said Thomson initially asked if he could train dogs to find wilding pines.
He suggested dogs could do that so easily they might get sensory overload so it would better to train them on something tougher.
People could find needle grass themselves without much trouble at certain times of the year but it was harder after a paddock had been grazed or mown.
Dogs usually had no trouble finding a single plant so Bowers was now training them to systematically work an area.
Thomson’s work was funded by a grant from Environment Canterbury and the Ministry for Primary Industries.
Dogs and handlers on needle grass properties would be were subject to the usual seed checks and wash-down protocols, including checks for seeds on vehicles, clothes and other equipment.
