Feb 22, 2020 09:00:00

It turns out that dogs can segregate `` incurable citrus disease '' with 99% accuracy before onset

It is known that dogs have a very sharp sense of smell. Some dogs are active as drug detection dogs at airports and others, and detect

human cancer with high accuracy. A newly published study reported that 'dogs can determine whether a citrus tree is infected with disease with high accuracy before symptoms appear.'

Canine olfactory detection of a vectored phytobacterial pathogen, Liberibacter asiaticus, and integration with disease control | PNAS
https://www.pnas.org/content/early/2020/01/28/1914296117

Can Disease-Sniffing Dogs Save the World's Citrus? | Innovation | Smithsonian Magazine
https://www.smithsonianmag.com/innovation/can-disease-sniffing-dogs-save-worlds-citrus-180974108/

Dog sleuths sniff out crop disease hitting citrus trees
https://apnews.com/28f6ee842b9c14092766fdf038c0c733

The

citrus greening disease , in which yellow spots appear on leaves and green spots appear on fruits due to pathogen infection, is spread by insects eating leaves, and there is no way to cure once infected, It is said to be one of the most serious citrus diseases.

Regarding citrus greening, which affects almost all citrus fruits, U.S. Department of Agriculture researcher Tim Gottwald says, 'It's like cancer. It can't be transferred to other trees and cured.' States. With citrus greening, visible symptoms do not appear immediately after infection with the pathogen. Trees have been infected with the pathogen several months to several years before symptoms such as spots appear.

The only way to prevent the spread of citrus greening disease is to cut down and remove infected trees, but this requires the early detection of diseased trees. However, it seems that it is difficult for even researchers to diagnose citrus greening disease from the infection of the pathogen until the visible symptoms appear, and as a result this time lag spreads the infection of citrus greening disease Is connected to

by

US Department of Agriculture

To achieve early detection of citrus greening disease, Gottwald et al.'S research team devised a method of 'training dogs to learn the odor of citrus that had citrus greening disease.' It seems that the change in odor due to citrus greening disease can not be perceived by humans, but the research team thought that dogs with excellent smell may be able to detect the change in odor.

In fact, the research team taught 20 dogs the smell of citrus that had developed citrus greening disease. The training period was a few weeks, but an experiment conducted in a grapefruit orchard in Texas said that the dog was able to separate the citrus tree from the healthy tree with 99% accuracy. 'I wasn't surprised that dogs could smell the citrus greening disease, but I was surprised that they showed surprisingly high precision,' Gottwald said.

The researchers are also conducting experiments that compare conventional DNA testing with dog testing, which was used to identify suspected infected trees. As a result, dogs were able to identify infected trees within a few weeks after the tree became infected with the pathogen, but DNA testing showed that two-thirds of the tree was 17 months after infection. It is said that only trees that hit the area could identify the infection.

'This could be a very exciting result for citrus growers,' said

Phuc Ha , a microbiologist at Washington University following the results of Gottwald's research. In the future, orchard operators have stated that dogs may become a fast and accurate way to identify citrus greening.