Influence of calcium, potassium, and magnesium on Cornus florida L. density and resistance to dogwood anthracnose

2006 ◽  
Vol 290 (1-2) ◽  
pp. 189-199 ◽  
Author(s):  
Eric J. Holzmueller ◽  
Shibu Jose ◽  
Michael A. Jenkins
Keyword(s):  
Cornus Florida ◽  
Dogwood Anthracnose

Influence of canopy microclimate on incidence and severity of dogwood anthracnose

1992 ◽  
Vol 70 (5) ◽  
pp. 1093-1096 ◽  
Author(s):  
Dan O. Chellemi ◽  
Kerry O. Britton
Keyword(s):  
Vapor Pressure ◽  
Air Temperature ◽  
Photosynthetically Active Radiation ◽  
Vapor Pressure Deficit ◽  
Disease Incidence ◽  
Cornus Florida ◽  
Active Radiation ◽  
Dogwood Anthracnose ◽  
Low Levels ◽  
Understory Trees

Incidence and severity of dogwood anthracnose within the interior and exterior canopies of exposed dogwood (Cornus florida L.) trees and canopies of understory trees were recorded over a 53-day period during the summer of 1990. Concurrent measurements of vapor pressure deficit, air temperature, evaporative potential, and photosynthetically active radiation within the canopies were also recorded. Disease incidence was significantly lower in the exterior canopy of exposed trees than in other canopy locations. Disease severity was significantly different among all three canopy locations, with the lowest severity in exterior canopies of exposed trees and the greatest severity in canopies of understory trees. Of the climatic variables measured, evaporative potential provided the most consistent contrast among microclimates at the various canopy locations. Mean evaporative potentials averaged over 6- to 10-day intervals ranged from 0.00 g H2O h−1 in understory and exposed, interior canopies to 0.40 g H2O h−1 in exposed, exterior canopies. Disease incidence and severity were greater in canopies associated with low levels of evaporative potential. Key words: Cornus florida L., dogwood anthracnose, canopy microclimate, evaporative potential.

scholarly journals Remote Sensing Techniques Coupled with Leaf Spectroscopy to Evaluate the Severity of Dogwood Anthracnose

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 827C-827
Author(s):  
Tara H. Hayes ◽  
Caula A. Beyl
Keyword(s):  
Remote Sensing ◽  
Image Analysis ◽  
Disease Severity ◽  
Mathematical Expression ◽  
Cornus Florida ◽  
Leaf Reflectance ◽  
Dogwood Anthracnose ◽  
Remote Sensing Techniques

Flowering dogwoods. (Cornus florida L.) have been attacked by dogwood anthracnose. In vivo leaf reflectance values of infected leaves from Summer 1993, Fall 1993, and Fall 1994 were obtained using a spectroreflectometer at wavelengths from 300 to 2500 nm to determine what wavelengths could best detect differences between dead and healthy leaves. At -those wavelengths, a mathematical expression was devised and used to calculate the predicted reflectance value for that percent disease severity (Rexp50%). The predicted reflectance values were compared with actual mean reflectance values (Rmean) obtained from leaves with up to 50% disease severity achieving correlations of 0.95, 0.66, and 0.84, for the Summer and Fall 1993, and Fall 1994, respectively. For Fall 1994, actual disease severity values were obtained by scanning and image analysis to compute an expected reflectance for these actual percentages (Rreal%) for a correlation value of 0.98.

scholarly journals Cornus florida `Appalachian Spring': A White Flowering Dogwood Resistant to Dogwood Anthracnose

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
Keyword(s):  
Cornus Florida ◽  
Flowering Dogwood ◽  
Dogwood Anthracnose

scholarly journals Light Intensity and Drought Stress as Predisposition Factors for Dogwood Anthracnose

1995 ◽  
Vol 13 (4) ◽  
pp. 186-189
Author(s):  
Dan K. Erbaugh ◽  
Mark T. Windham ◽  
Ann J.W. Stodola ◽  
Robert M. Augé
Keyword(s):  
Drought Stress ◽  
Light Intensity ◽  
Disease Progression ◽  
Disease Severity ◽  
Cornus Florida ◽  
Ambient Light ◽  
Inoculation Methods ◽  
Anthracnose Disease ◽  
Discula Destructiva ◽  
Dogwood Anthracnose

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.

scholarly journals Honeybee-mediated Controlled Pollinations in Cornus florida and C. kousa Intra- and Interspecific Crosses

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 ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Seed Production ◽  
Interspecific Crosses ◽  
Cornus Florida ◽  
Breeding Lines ◽  
Flowering Dogwood ◽  
Dogwood Anthracnose ◽  
Ornamental Trees ◽  
Ornamental Traits ◽  
Simple Sequence

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.

Effect of acid deposition on trichome morphology and dogwood anthracnose biology

1992 ◽  
Vol 50 (1) ◽  
pp. 840-841
Author(s):  
Kyle T. Thornham ◽  
R. Jay Stipes ◽  
Randolph L. Grayson
Keyword(s):  
Acid Deposition ◽  
Disease Incidence ◽  
Natural Populations ◽  
Tree Disease ◽  
Flowering Dogwood ◽  
Discula Destructiva ◽  
Disease Induction ◽  
Dogwood Anthracnose ◽  
Trichome Morphology ◽  
Precipitation Events

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.

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