Editing Chestnut blight (section)

==Management: hypovirulence, sanitation, and chemical control==
In Europe, during the late 1960s, it was found that a strain of ''C. parasitica'' was less virulent, only able to produce shallow cankers that the tree's callus tissue could eventually limit and isolate. The trait of hypovirulence could be transferred from an avirulent strain to a lethal strain through [[anastomosis]]—the fusion of hyphae.<ref name=":2">{{Cite journal|last=Nuss|first=Donald|date=1992|title=Biological control of chestnut blight: an example of virus-mediated attenuation of fungal pathogenesis|journal=Microbiological Reviews|volume=56 | issue = 4 |pages=561–576|doi=10.1128/MMBR.56.4.561-576.1992|pmid=1480109|pmc=372888}}</ref> It was later discovered that this attenuated virulence was due to infection by a [[dsRNA]] [[mycovirus]], ''Cryphonectria hypovirus 1'' (CHV1) of genus ''[[Hypovirus]]''.<ref name=":3">{{Cite journal|vauthors=Kazmierczak P, McCabe P, Turina M, Wilk DJ, Van Alfen NK|date=June 2012|title=The Mycovirus CHV1 Disrupts Secretion of a Developmentally Regulated Protein in ''Cryphonectria parasitica''|journal=Journal of Virology|volume=86 | issue = 11 |pages=6067–6074|doi=10.1128/jvi.05756-11|pmid=22438560|pmc=3372201}}</ref><ref name="ACF-biocontrol" />

Considering the nature of hypovirulent strains, there has been a strong interest to use them to manage lethal ''C. parasitica'' strains. In Europe, natural dissemination of hypovirulence in pathogen populations resulted in the restoration of economically valuable chestnuts.<ref name=":2" /> Unfortunately, this was not the case in the United States. Compared to Europe, the US has a greater diversity of ''C. parasitica'' strains.<ref>{{Cite journal|last=Thompson|first=Helen|date=October 2012|title=Plant science: the chestnut resurrection|journal=Nature|volume=490|issue=7418|pages=22–23|doi=10.1038/490022a|pmid=23038446|bibcode=2012Natur.490...22T|doi-access=free}}</ref> Thus, the spread of the mycovirus in American ''C. parasitica'' populations is inhibited by vegetative incompatibility, an [[allorecognition]] system that inhibits the fusion of hyphae between individuals that are genetically distinct at specific loci.<ref name=":3" /><ref name=":2" /> In 2016, however, "super mycovirus donor strains" of ''C. parasitica'' were engineered to overcome this incompatibility system.  This could potentially be employed as a method of biological control.<ref>{{Cite journal|vauthors=Zhang DX, Nuss DL|date=2016|title=Engineering super mycovirus donor strains of chestnut blight fungus by systematic disruption of multilocus vic genes|journal=PNAS|volume=113 | issue = 8 |pages=2062–2067|doi=10.1073/pnas.1522219113|pmid=26858412|pmc=4776480|bibcode=2016PNAS..113.2062Z|doi-access=free}}</ref>

As mentioned above some soil microorganisms suppress ''C. parasitica''. This can be used to treat the cankers, by using a soil compress, a quantity of soil held against the trunk itself with [[plastic wrap]] and some [[adhesive tape]] around that.<ref name="ACF-biocontrol" />

In addition to biocontrol, chestnut blight can also be managed by sanitation practices and chemical control; however, such management strategies are only feasible on a small scale, such as in an orchard. Sanitation practices like the pruning of symptomatic limbs and removal of infected trees can serve to eliminate sources of inoculum and limit the spread of the pathogen.<ref name="Chestnut blight"/>

Additionally, some fungicides may be effective at controlling this fungal disease. A study on the chemical control of chestnut blight in ''Castanea sativa'', may have found that the external application of both [[copper oxychloride]] and [[carbendazim]] could reduce the rate of disease by almost 50%.<ref>{{Cite journal|vauthors= Trapiello, Estefanía, et al.|title=Chestnut Blight Control by Agrochemicals in Castanea Sativa under Managed Conditions|journal= Journal of Plant Diseases and Protection |volume= 122 |issue=3 |publisher=Verlag Eugen Ulmer KG |year=2015 |pages=120–24 |doi=10.1007/BF03356540|jstor=24618945|s2cid=87736296 }}</ref>