Stegophora ulmea | |
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Symptoms of black spot on elm in the summer | |
Symptoms of black spot on an elm leaf in the fall | |
Scientific classification | |
Kingdom: | |
Division: | |
Class: | |
Order: | |
Family: | |
Genus: | |
Species: | S. ulmea
|
Binomial name | |
Stegophora ulmea (Fr.) Syd. & P. Syd., (1916)
| |
Synonyms | |
Asteroma ulmeum (Miles) B. Sutton, (1980) |
Stegophora ulmea is a foliar disease of elms commonly known as black spot of elm, twig blight, and elm leaf scab. [1] It is characterized by yellow spots that become black spots on the leaves. The pathogen is an ascomycete fungus native to North America. Stegophora ulmea is its teleomorph name. [2] It has two anamorph names, Gloeosporium ulmicolom referring to the macroconidia stage and Cylindrosporella ulmea referring to the microconidia stage. [1] This pathogen was formerly known as Gnomonia ulmea [3].
Stegophora ulmea infects all Ulmus species and Japanese zelkova. [2] It is most virulent on American white elm, Ulmus Americana [1]. Other elms it is known to infect include: [1]
Stegophora ulmea is characterized by chlorotic yellow spots 1 millimeter in diameter with a black center that develop early in the spring. [1] [2] [4] They darken and become raised. The black center can increase to occupy the entire chlorotic area. [4] The black spots can become about 5 millimeters in diameter. [1] As the season continues, the tissue around the original spot may become necrotic. [4] In severe cases of the disease there is premature shedding of leaves, blight of young leaves and shoots, and complete defoliation early in the fall. [1] Fruits that are infected become crumpled. [1] Infection of mature trees is rarely fatal. [1] [2]
In the spring, new leaves are infected with ascospores which develop from the survival structure, perithecia, found in leaf debris. [1] It is thought that inoculum from overwintered buds can also result in infection. [1] [4] The perithecia are the structure in which S. ulmea survives the winter. Ascospore release is synchronized with the foliar development of the elms. [4] Ascospores commonly infect lower leaves and leaves near the bud. [1] A period of wetness and dryness with a temperature over 7 degrees Celsius is required before ascospores are released. [1] The ascospores disperse through the air and have the potential to travel over long distances. [1] Acervuli develop in the center of the lesions. [1] Acervuli can release macroconidia, which are white. [1] They mature 10–20 days after infection. [1] During spring and early summer, the macroconidia act as a secondary inoculum. This is the asexual part of S. ulmea’s life cycle. [1] Water is necessary for the dispersal of the macroconidia. [1] Microconidia are produced in the lesions during midsummer. [1] They act as spermatia in the sexual stage of the S. ulmea’s life cycle. [1] During late summer and fall perithecia, the sexual structure, begins to develop. [1]
Sanitation, or removal all leaf debris seems to be the best method of control. [1] In commercial growing arenas, it is suggested that overhead watering should not be used, because it helps spread the pathogen. [1] Resistance greatly varies between species. [1] U. thomasfi seems to be the most resistant. [4] The majority of elms seem to be tolerant. [4] A dominant gene conferring resistance to U. parvifolia was discovered, though it did not provide absolute resistance. [5] There is currently no information about fungicides used to control this disease. [1] This disease is not typically fatal and is not actively addressed. [3] Aeration seems to moderately reduce growth and sporulation. [6] Cool temperatures and high humidity enhance the disease, so avoidance of these conditions will decrease the prevalence of disease.
{{
cite web}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
Stegophora ulmea | |
---|---|
Symptoms of black spot on elm in the summer | |
Symptoms of black spot on an elm leaf in the fall | |
Scientific classification | |
Kingdom: | |
Division: | |
Class: | |
Order: | |
Family: | |
Genus: | |
Species: | S. ulmea
|
Binomial name | |
Stegophora ulmea (Fr.) Syd. & P. Syd., (1916)
| |
Synonyms | |
Asteroma ulmeum (Miles) B. Sutton, (1980) |
Stegophora ulmea is a foliar disease of elms commonly known as black spot of elm, twig blight, and elm leaf scab. [1] It is characterized by yellow spots that become black spots on the leaves. The pathogen is an ascomycete fungus native to North America. Stegophora ulmea is its teleomorph name. [2] It has two anamorph names, Gloeosporium ulmicolom referring to the macroconidia stage and Cylindrosporella ulmea referring to the microconidia stage. [1] This pathogen was formerly known as Gnomonia ulmea [3].
Stegophora ulmea infects all Ulmus species and Japanese zelkova. [2] It is most virulent on American white elm, Ulmus Americana [1]. Other elms it is known to infect include: [1]
Stegophora ulmea is characterized by chlorotic yellow spots 1 millimeter in diameter with a black center that develop early in the spring. [1] [2] [4] They darken and become raised. The black center can increase to occupy the entire chlorotic area. [4] The black spots can become about 5 millimeters in diameter. [1] As the season continues, the tissue around the original spot may become necrotic. [4] In severe cases of the disease there is premature shedding of leaves, blight of young leaves and shoots, and complete defoliation early in the fall. [1] Fruits that are infected become crumpled. [1] Infection of mature trees is rarely fatal. [1] [2]
In the spring, new leaves are infected with ascospores which develop from the survival structure, perithecia, found in leaf debris. [1] It is thought that inoculum from overwintered buds can also result in infection. [1] [4] The perithecia are the structure in which S. ulmea survives the winter. Ascospore release is synchronized with the foliar development of the elms. [4] Ascospores commonly infect lower leaves and leaves near the bud. [1] A period of wetness and dryness with a temperature over 7 degrees Celsius is required before ascospores are released. [1] The ascospores disperse through the air and have the potential to travel over long distances. [1] Acervuli develop in the center of the lesions. [1] Acervuli can release macroconidia, which are white. [1] They mature 10–20 days after infection. [1] During spring and early summer, the macroconidia act as a secondary inoculum. This is the asexual part of S. ulmea’s life cycle. [1] Water is necessary for the dispersal of the macroconidia. [1] Microconidia are produced in the lesions during midsummer. [1] They act as spermatia in the sexual stage of the S. ulmea’s life cycle. [1] During late summer and fall perithecia, the sexual structure, begins to develop. [1]
Sanitation, or removal all leaf debris seems to be the best method of control. [1] In commercial growing arenas, it is suggested that overhead watering should not be used, because it helps spread the pathogen. [1] Resistance greatly varies between species. [1] U. thomasfi seems to be the most resistant. [4] The majority of elms seem to be tolerant. [4] A dominant gene conferring resistance to U. parvifolia was discovered, though it did not provide absolute resistance. [5] There is currently no information about fungicides used to control this disease. [1] This disease is not typically fatal and is not actively addressed. [3] Aeration seems to moderately reduce growth and sporulation. [6] Cool temperatures and high humidity enhance the disease, so avoidance of these conditions will decrease the prevalence of disease.
{{
cite web}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)