Occurrence of Flowering Dogwood (Cornus florida L.), and Mortality by Dogwood Anthracnose (Discula destructiva Redlin), on the Northern Allegheny Plateau

1999 ◽  
Vol 126 (4) ◽  
pp. 313 ◽  
Author(s):  
Charles E. Williams ◽  
William J. Moriarity
Author(s):  
Kyle T. Thornham ◽  
R. Jay Stipes ◽  
Randolph L. Grayson

Dogwood anthracnose, caused by Discula destructiva (1), is another new catastrophic tree disease that has ravaged natural populations of the flowering dogwood (Cornus florida) in the Appalachians over the past 15 years, and the epidemic is prognosticated to continue (2). An estimated 9.5 million acres have been affected, primarily in the Appalachian Mountains, from VA southwards, alone, and an estimated 50% of all dogwoods in PA have been killed. Since acid deposition has been linked experimentally with disease induction, and since the disease incidence and severity are more pronounced at higher elevations where lower pH precipitation events occur, we investigated the effect of acidic foliar sprays on moiphologic changes in the foliar cuticle and trichomes (3), the initial sites of infection and foci of Discula sporulation.


HortScience ◽  
1998 ◽  
Vol 33 (7) ◽  
pp. 1265-1267 ◽  
Author(s):  
M.T. Windham ◽  
E.T. Graham ◽  
W.T. Witte ◽  
J.L. Knighten ◽  
R.N. Trigiano

1994 ◽  
Vol 12 (2) ◽  
pp. 61-64
Author(s):  
James L. Sherald ◽  
Tammy M. Stidham ◽  
Libby E. Roberts

Abstract Eight species and one cultivar of Cornus: C. florida L. (flowering dogwood), C. kousa (Buerger ex Miquel) Hance (Chinese dogwood), C. alba L. (Siberian dogwood), C. alternifolia L. (pagoda dogwood), C. sericea L. (red-osier dogwood), C. sericea ‘Flaviramea’ (yellow twig dogwood), C. racemosa Lam. (gray stem dogwood), C. amomum Mill, (silky dogwood), and C. mas L. (Cornelian cherry) were subjected to natural infection by Discula destructiva for two or three years. The area of exposure exhibited a 35% increase in mortality of native C. florida over a four year period. Only the eight C. florida test plants developed dogwood anthracnose symptoms and six of these plants died after three years. All other species remained free of dogwood anthracnose. Under more severe disease conditions other Cornus species may develop dogwood anthracnose. Ideally, resistance testing should be performed under laboratory or greenhouse conditions where inoculum and environmental conditions can be controlled.


1995 ◽  
Vol 13 (4) ◽  
pp. 186-189
Author(s):  
Dan K. Erbaugh ◽  
Mark T. Windham ◽  
Ann J.W. Stodola ◽  
Robert M. Augé

Abstract Light and drought stress were studied as predisposition factors for dogwood anthracnose. Disease progression was recorded as a percentage of leaves with lesions in two-year-old potted dogwood trees (Cornus florida L.) that had been inoculated with dogwood anthracnose (Discula destructiva Redlin sp. nov.) and subjected to four light (100%, 50%, 10% and 2% ambient light) and two drought treatments. Natural vs.artificial inoculation methods were compared and found to have similar effects on disease severity. Shade increased disease severity; maximum disease progression values for trees in thoroughly watered treatments were about 5% at 100% light and 50% light, 35% at 10% light, and 26% at 2% light. Drought increased disease severity on all shaded trees, where disease progression increased 625% in 50% light, 43% in 10% light and 31% in 2% light, compared to 100% light. Drought had no effect on disease severity of unshaded trees.


HortScience ◽  
2009 ◽  
Vol 44 (6) ◽  
pp. 1527-1533 ◽  
Author(s):  
Phillip A. Wadl ◽  
John A. Skinner ◽  
John R. Dunlap ◽  
Sandra M. Reed ◽  
Timothy A. Rinehart ◽  
...  

Flowering (Cornus florida L.) and kousa (C. kousa Hance) dogwoods are ornamental trees valued for their four-season appeal, but also for their importance to retail and wholesale nurseries. The popularity of kousa dogwood has increased in recent years as a result of its resistance to dogwood anthracnose and powdery mildew as compared with flowering dogwood, which is typically susceptible to those diseases. This range of resistance allows the development of intra- and interspecific cultivars with multiple disease resistance or a combination of disease resistance and specific ornamental traits. Breeding requires controlled crosses that are usually done manually, which is a labor-intensive process. Cornus florida and C. kousa have generally been found to be self-incompatible allowing for the breeding process to be made more efficient by not having to emasculate flowers. We have capitalized on the natural ability of honeybees and the self-incompatible nature of dogwood to perform self- and crosspollinations of flowering and kousa dogwood. Self-pollinations were conducted in 2006 and 2007 with C. florida ‘Appalachian Spring’ and ‘Cherokee Brave’ and with C. kousa ‘Blue Shadow’ and Galilean®. The flowering dogwood self-pollinations resulted in no seed production, whereas the kousa dogwood self-pollinations resulted in low seed production, indicating self-incompatibility. Intra- and interspecific crosses of flowering and kousa dogwood cultivars and breeding lines were conducted in 2006 to 2008. Honeybees were effective in facilitating seed production for all intraspecific crosses conducted. Seedling phenotypes of putative intra- and interspecific hybrids are similar and practically indistinguishable, so dogwood-specific simple sequence repeats were used to verify a sample of the putative hybrids. The results demonstrated that honeybees were effective in performing controlled pollinations and that honeybee-mediated pollinations provide an alternative to time-consuming hand pollinations for flowering and kousa dogwood.


2000 ◽  
Vol 18 (3) ◽  
pp. 154-159
Author(s):  
Austin Hagan ◽  
Jackie Mullen

Abstract In North Alabama, dogwood anthracnose (Discula destructiva) was the most common and damaging disease identified in stands of native flowering dogwood (Cornus florida). In the spring of 1992 and 1993, this disease was observed at 59% and 64%, respectively, of the forest and park sites surveyed. Highest incidence and severity of dogwood anthracnose was recorded in the Appalachian Mountains and adjoining foothills of the Piedmont at elevations of 372 to 558 m (1200 to 1800 ft) in the northeastern corner of Alabama near Georgia and Tennessee. At selected sites in Cherokee, Cleburne, DeKalb, Jackson, and Madison Counties, approximately 90% to 100% of the trees examined displayed diagnostic symptoms of dogwood anthracnose. Extensive blighting of the leaves, shoot dieback, epicormic shoot formation, and sometimes tree death were noted. Lower levels of anthracnose damage were recorded on trees in several additional counties in northeast Alabama. Survey results indicate that this disease has not spread onto flowering dogwood in other counties in North Alabama. Spot anthracnose (Elsinoe corni) and Botrytis blight (Botrytis cinerea) were found far less frequently and at fewer locations on flowering dogwood than dogwood anthracnose. Typically, damage attributed to either disease was unobtrusive and of little threat to tree health.


1926 ◽  
Vol 68 (2) ◽  
pp. 399-402
Author(s):  
Raymond M. Hann ◽  
Charles E. Sando

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