Dogs can detect laurel wilt in avocado orchards Credit: iStockphoto The sensitivity of the dog nose is legendary, 10,000-100,000 times more sensitive than the human nose, and capable of detecting odour concentrations at one to two parts per trillion. So the use of dogs to detect illegal drugs, for example, is now routine, and detection of human cancers and Covid-19 seems a realistic prospect. Naturally enough, the thoughts of botanists have turned to using dogs to detect disease in plants. One example is laurel wilt, a fungal disease of avocado, which has recently become a problem in Florida’s avocado orchards since the introduction from Asia of the redbay ambrosia beetle. The beetles inoculate avocado trees with the fungus as they bore into the wood, which is great for the beetles, which use fungal “gardens”within excavated galleries as a food source, but not so good for the trees, whose attempts to defend themselves lead to blocked xylem and ultimately death.