Swedish project finds detection dogs spot weeds that people struggle to see
In a project backed by Swedish farm cooperative Lantmännen, detection dogs found very small weed plants directly in a growing crop during a field trial. The project now moves to its data analysis phase.
A project in Sweden testing whether trained detection dogs can find weeds in crop fields has reported its first successes. The initiative is supported by Lantmännen, a Swedish agricultural cooperative. According to the cooperative, dogs on a trial field located very small weed plants directly within the growing crop, plants that are hard for people to detect. The project is now entering its analysis phase.
How the trial worked
A dog handler and her dog searched for weeds in harvested rye. The dog found very small plants, which were recorded by GPS. The results were then compared with plants identified by an experienced adviser.
Linda Öhlund, Senior Plant Breeder at the cooperative, explained that the dogs' strength lies in searching for the scent of the weeds rather than trying to tell them apart from the crop by eye. In the long term, she said, it would also be interesting to see how the dogs' sense of smell can be combined with human judgment and with technologies such as drones and AI.
Weeds studied
The trials covered common cocklebur-type species named in the source as gewöhnliches Kletten-Kraut, along with barnyard grass, tall fescue and velvet grass. Lantmännen describes these as grass weeds that are difficult to recognise in their early stage and may require special measures.
International findings and next steps
Pär-Johan Lööf, head of agricultural research and development at Lantmännen, called the results so far very interesting. He noted that international research suggests dogs may have an advantage when weeds are still very small. An American field study produced similar results: trained dogs found small seedlings of one weed species more often than humans did, though the difference was smaller with larger plants.
The project began in 2025. Preparation and fieldwork are complete, and all data will now be analysed. The practical potential of the method will then be assessed, along with the areas where detection dogs could offer farmers the greatest benefit.
