Thousand Cankers Disease

Another new pest could be coming our way. Thousand Cankers Disease has be identified in Tennessee. Thousand Cankers Disease (TCD)is a disease of Black Walnut. TCD poses a serious problem to the health of the black walnut tree. Walnut trees are important because of their nut crop and the desired wood for various products. TCD is a progressive disease that kills a tree within two to three years after initial infection. The disease-causing fungus, Geosmithia, is transmitted by the walnut twig beetle. Branches and trunk tissue are killed by repeated infections by the fungus, as the beetles carry the fungus into new bark cambium tissue.

The North Carolina Department of Agriculture and Consumer Services has issued a quarantine of all plants or plant part of the genus Juglans coming into the state from Tennessee and many other western states that already have Thousand Cankers Disease established.

Spruce Spider Mite

Growers should be keeping a watch for spruce spider mite with the hot, dry weather we have been having recently. Growers should be scouting to determine the presence of mites and they should review the economic thresholds to determine if or when they would need to treat.

The economic thresholds used by most growers are listed below. However, each grower has different needs for tree quality. These numbers should be adjusted up or down by each grower based on his or her own experience and needs.

Size of Tree
Less than waist high 40%
Waist high to year before sale 20%
Year of sale 10%

*Percentage of infested shoots to sampled shoots