Dogs search for diseased apple trees

A project is now underway in several apple orchards to train dogs to search for canker disease. The disease is widespread and causes significant damage to Swedish apple trees every year.

Fruit tree canker, a fungal disease that affects about one in ten apple trees in Sweden, is a major challenge for the country’s apple growers. The disease spreads through wounds in the trees and is often not noticed until it is too late, causing decay that spreads throughout the tree. In some cases, the fungus can also attack the fruit, often only becoming apparent during storage.

– It takes three to five years before the disease breaks out, and then in some cases it can affect almost the entire crop, Larisa Gustavsson, a researcher at the Department of Plant Breeding at the Swedish University of Agricultural Sciences, SLU, tells forskning.se.

Almost two years ago, the project “Detection of fruit pests with special search dogs” was launched, in which researchers from the Swedish University of Agricultural Sciences work together with Green Innovation Park, Kiviks Musteri, Äppelriket and dog teams to see if dogs are able to detect the disease.

In addition to drugs, dogs can also be trained to find missing people, pests and archaeological remains. For example, Marie Koenen, who is participating in the project with her Spanish street dog Sniff, has trained special search dogs to look for bedbugs and black-headed snails. A total of eight dogs and their owners are involved.

The results show that dogs can search for fruit tree canker.

– We started with a very high concentration of fungal spores. Now we are down to relatively low concentrations, says Koenen.

Sweden’s largest fruit sector

However, the project is time-consuming. The dogs are trained over weekends, where they gradually learn to identify increasingly faint scents. Once a dog marks an apple tree, it takes at least three months to determine whether the tree is actually affected by the disease.

The project will end this October, but Koenen says they plan to apply for funding to continue.

– We believe in this, it has to take the time it needs.

Apple growing is Sweden’s largest fruit sector, with almost 90 percent of orchards concentrated in Skåne. About 30 percent of the apples sold in Swedish stores come from domestic production.