From New York Times article: "Scientists trained dogs to sniff out a crop disease called citrus greening that has hit orange, lemon and grapefruit orchards in Florida, California and Texas. The dogs can detect it weeks to years before it shows up on tree leaves and
roots, the researchers report.
“This technology is thousands of years old – the dog’s nose,” said Timothy Gottwald, a researcher with the U.S. Department of Agriculture and a co-author of the study. “We’ve just trained dogs to hunt new prey: the bacteria that causes a very damaging crop disease.” "
The article is very short, but I found it interesting.
New York Times - dog - citrus