Dogs are already used to sniff out drugs and explosives at ports and airports. Now, they are being trained to identify pests and pathogens with the potential to devastate British woodlands. Zinc, a three-year-old cocker spaniel, attended the Chelsea Flower Show last week, to publicise the scheme. Zinc has been trained to detect Phytophthora ramorum, which can kill native trees, including oaks. Dogs can quickly screen large areas such as commercial nurseries and ports; they can also navigate dense woodland. But Zinc’s handler stressed that they can get “nasal fatigue”, and so they search for only three to four hours a day, and have plenty of rest breaks.