The
Christmas Tree:
RELATED SITES
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In the PNW and North Carolina this is the most important disease of noble and Fraser fir Christmas trees. As growers have tried to expand plantings to lower elevation and heavier textured soils, losses from this disease can reach 30% to 75% in unfavorable sites (Benson and Grand, 1999 and Chastagner et al., 1995). Because infested sites can no longer be used to produce noble and Fraser fir, this disease severely limits the ability of growers to increase the production of these species. Recent work in North Carolina indicates that overall industry losses from this disease are 8.9% of the production or $9 million. |
Above ground symptoms associated with Phytophthora root rot and stem canker include chlorosis of foliage, wilting of new growth, branch flagging, stunting and death of the tree. Needles on branches and trees killed by Phytophthora root rot have a distinct reddish-brown appearance. Roots will typically have a reddish brown discoloration of the cambium region, which may extend up the stem, particularly on noble fir. In some situations, Phytophthora species also cause a shoot blight. Initial symptoms associated with shoot blight consist of a reddening of the needles at the tips of the shoots during late spring and early summer. The wood beneath the bark is medium brown with a distinct margin between the dead and healthy tissue. The infection can spread down the shoots and branches into the stem of the tree and affected branches can occur anywhere on the tree.
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1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | References © Copyright 1999 by the American Phytopathological Society. All rights reserved.
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