Rhytisma acerinum

clean up, typo(s) fixed: a economically → an economically using AWB

← Previous revision		Revision as of 21:37, 31 August 2015
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	==Disease cycle==		==Disease cycle==
−	''R. acerinum'' is the [[teleomorph]] of Tar Spot. In the spring, needle-shaped [[ascospores]] are released from overwintering [[apothecia]] in fallen leaf debris.<ref name="Weber and Webster"/><ref name="Hsiang">Hsiang, T, LX Tian, and C Sopher. "Non-native Hosts and Control of Rhytisma Acerinum Causing Tar Spot of Maple." Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 31.4 (2009): 488.</ref> These spores are disseminated by the wind and have a sticky coat to attach to new healthy leaves.<ref name="Cornell University">Cornell University. Tar Spots of Maple. May 2011. Web. 22 Oct. 2011. <http://ift.tt/1JHBh75; Once on the leaves, the spores germinate and penetrate through the [[stoma]].<ref name="Weber and Webster"/> The subsequent infection causes [[chlorosis]] of the leaves in localized yellow spots. As the season continues into summer, apothecia begin to form, giving rise to brown-black leaf lesions that resemble spots of tar.<ref name="Weber and Webster"/> Leaves retain their yellow border from the initial chlorosis. Apothecia survive in the fallen plant debris over winter, releasing spores when the temperature is warm again.<ref name="University of Nebraska"/> The infection of Tar Spot is localized to the chlorotic areas on the leaves and is mostly a cosmetic issue, rather than a economically detrimental disease.<ref name="University of Nebraska"/>	+	''R. acerinum'' is the [[teleomorph]] of Tar Spot. In the spring, needle-shaped [[ascospores]] are released from overwintering [[apothecia]] in fallen leaf debris.<ref name="Weber and Webster"/><ref name="Hsiang">Hsiang, T, LX Tian, and C Sopher. "Non-native Hosts and Control of Rhytisma Acerinum Causing Tar Spot of Maple." Canadian Journal of Plant Pathology-revue Canadienne De Phytopathologie, 31.4 (2009): 488.</ref> These spores are disseminated by the wind and have a sticky coat to attach to new healthy leaves.<ref name="Cornell University">Cornell University. Tar Spots of Maple. May 2011. Web. 22 Oct. 2011. <http://ift.tt/1JHBh75; Once on the leaves, the spores germinate and penetrate through the [[stoma]].<ref name="Weber and Webster"/> The subsequent infection causes [[chlorosis]] of the leaves in localized yellow spots. As the season continues into summer, apothecia begin to form, giving rise to brown-black leaf lesions that resemble spots of tar.<ref name="Weber and Webster"/> Leaves retain their yellow border from the initial chlorosis. Apothecia survive in the fallen plant debris over winter, releasing spores when the temperature is warm again.<ref name="University of Nebraska"/> The infection of Tar Spot is localized to the chlorotic areas on the leaves and is mostly a cosmetic issue, rather than an economically detrimental disease.<ref name="University of Nebraska"/>
	The [[anamorph]] of Tar Spot is ''Melasmia acerina''.<ref name="University of Nebraska"/> In late summer, [[conidiophores]] are formed in the mass of fungal tissue called the stroma. [[Stromatolite|Stroma]] is located in the black lesions of the infected leaves.<ref name="Weber and Webster"/> Conidiophores form non-infectious [[conidia]] that are released both in conditions of wetness and drought.<ref name="Weber and Webster"/><ref name="Hsiang"/> The most favorable environment for the pathogen is when there is an extended period of moisture such as fog or rain, which prevents the leaves from drying out.<ref name="US. Maine Forest Service">US. Maine Forest Service. Maine Dept of Conservation. Tar Leaf Spot of Norway Maple. 2009. Web. 22 Oct. 2011. <http://ift.tt/1KA2cqz; Young trees growing in shade are therefore more susceptible. Under these conditions, conidiophores excrete a milky substance of conidia.<ref name="Weber and Webster"/> In times of drought, the conidia stick together as one unit and form yellowish tendrils.<ref name="Weber and Webster"/> Because the conidia are not infectious, this stage is not seen as often as the teleomorph, and it is not certain why the spores are produced.<ref name="Weber and Webster"/>		The [[anamorph]] of Tar Spot is ''Melasmia acerina''.<ref name="University of Nebraska"/> In late summer, [[conidiophores]] are formed in the mass of fungal tissue called the stroma. [[Stromatolite|Stroma]] is located in the black lesions of the infected leaves.<ref name="Weber and Webster"/> Conidiophores form non-infectious [[conidia]] that are released both in conditions of wetness and drought.<ref name="Weber and Webster"/><ref name="Hsiang"/> The most favorable environment for the pathogen is when there is an extended period of moisture such as fog or rain, which prevents the leaves from drying out.<ref name="US. Maine Forest Service">US. Maine Forest Service. Maine Dept of Conservation. Tar Leaf Spot of Norway Maple. 2009. Web. 22 Oct. 2011. <http://ift.tt/1KA2cqz; Young trees growing in shade are therefore more susceptible. Under these conditions, conidiophores excrete a milky substance of conidia.<ref name="Weber and Webster"/> In times of drought, the conidia stick together as one unit and form yellowish tendrils.<ref name="Weber and Webster"/> Because the conidia are not infectious, this stage is not seen as often as the teleomorph, and it is not certain why the spores are produced.<ref name="Weber and Webster"/>

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