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.
Showing posts with label Disease. Show all posts
Showing posts with label Disease. Show all posts
Friday, September 17, 2010
Monday, June 8, 2009
Downy Mildew In N.C.
Downy Mildew has been identified on a field of cucumbers in Franklin County, North Carolina. Downy mildew, caused by the fungus Pseudoperonospora cubensis, is found annually on squash, cucumbers, pumpkins, and muskmelons grown in all areas. Symptoms of disease on cucurbits, other than watermelon, show up as small yellowish areas on the upper leaf surface. Later, a more brilliant yellow coloration occurs with the internal part of the lesion turning brown.
Usually the spots will be angular as they are somewhat restricted by the small leaf veins. When the leaves are wet, a downy white-gray-light blue fungus growth can be seen on the underside of individual spots (lesions). On watermelons, yellow leaf spots may be angular or non-angular, and they will later turn brown to black in color. Often on watermelons, an exaggerated upward leaf curling will occur.
Downy mildew is a very destructive disease and progresses rapidly under favorable conditions. Fungicides are much more effective when applied well before symptoms are visible. Initiating a downy mildew control program after symptoms have been detected is much more likely to fail. For further information on control and how to track the movement of downy mildew throughout North Carolina go to the following website. http://www.ces.ncsu.edu/depts/pp/cucurbit/
Usually the spots will be angular as they are somewhat restricted by the small leaf veins. When the leaves are wet, a downy white-gray-light blue fungus growth can be seen on the underside of individual spots (lesions). On watermelons, yellow leaf spots may be angular or non-angular, and they will later turn brown to black in color. Often on watermelons, an exaggerated upward leaf curling will occur.
Downy mildew is a very destructive disease and progresses rapidly under favorable conditions. Fungicides are much more effective when applied well before symptoms are visible. Initiating a downy mildew control program after symptoms have been detected is much more likely to fail. For further information on control and how to track the movement of downy mildew throughout North Carolina go to the following website. http://www.ces.ncsu.edu/depts/pp/cucurbit/
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