"There is no assurance those resistant trees will be resistant to other strains from California, if they are introduced," said Garbelotto. "If another strain were to be introduced into the Mediterranean or in the Southern Hemisphere, this could accelerate and worsen the epidemic in those regions. It could nullify a 30-year long effort to develop trees that are resistant to the pathogen.
"It is imperative to stop the movement of infected plants in order to avoid further introductions that could completely overcome those lines of resistant trees."
Be careful what you plant
The new study spotlights the hazards of planting trees and other vegetation in regions where they are not native. Garbelotto said consumers should be careful about what they choose to plant in their backyards.
"Gardeners tend to pick the easiest plant to grow," said Garbelotto. "Monterey cypress became very popular in Europe because they grow faster, and they grow really well along the shore, while the Italian cypress is better suited for inland regions. The popularity of the Monterey cypress may have inadvertently led to the devastating spread of a deadly fungus throughout the world."
Garbelotto added that the cypress canker pathogen is so aggressive that, even in California, it can kill trees that are planted outside of their natural range.
"When Monterey cypress trees are planted in Monterey or along the coast, they are resistant to the disease," said Garbelotto. "That suggests that in coastal areas, the environment is unfavorable for development of infections, despite the pathogen having been in California for a long time. The pathogen emerges when we place the tree in a foreign environment."
Garbelotto said that chemical treatments for cypress canker disease may become available in the near future, but they are costly, and their effects on the
|Contact: Sarah Yang|
University of California - Berkeley