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Thousand Cankers Disease poses a significant threat to our billion dollar hardwoods industry, as Pennsylvania walnut is considered the best in the world," said Agriculture Secretary George Greig.
Spores of the pathogen are carried on the vector's body and infect the host tissue; the cankers produced by the pathogen coalesce and can girdle a trunk or branch, and in severe cases can cause decline and death of the tree.
Identified in Boulder and Colorado Springs in 2008, Thousand Cankers has resulted in the death of 60 percent of the walnuts in Boulder and has spread to Denver, Longmont, Pueblo and Canon City.
A 1995 USDA Forest Service study estimated that the canker was responsible for widespread damage to butternut trees, resulting in the toss of almost 77 percent of the butternuts in the Southeast.
The disease causes a black gummy substance to ooze from the bark and the tissue under the canker is killed.
He visits other chestnut trees, too, packing mud on their cankers and clipping flowers for use in breeding programs.
Thousand Cankers Disease attacks walnut trees when fungus-carrying Walnut Twig Beetles tunnel beneath the bark and form cankers that starve the tree of nutrients.
Both diseases seem to start with bleeding cankers in bark, though.
At least two-thirds of Wisconsin's butternuts have visible cankers, and death awaits them.
12, 2011 /PRNewswire-USNewswire/ -- Thousand Cankers Disease has been detected for the first time in Pennsylvania, and a quarantine restricting the movement of wood from Bucks County and other states known to have the disease is effective immediately.
Cankers develop on the trunk, sometimes encircling the tree but rarely killing it.
It was infested with multiple cankers that contained asexually reproducing fruiting bodies.