Editing Longan (section)

== Diseases ==
Plant based diseases can affect both longan fruits and their trees, and the severity of these diseases can range from harmless cosmetic damage to rendering to the fruit inedible.

The most prevalent disease among longan plants is [[witch's broom]], which can be found in all major longan-producing Asian territories, including China, Thailand, and Vietnam.<ref>{{Cite journal |last1=Olesen |first1=T. |last2=Menzel |first2=C. M. |last3=Wiltshire |first3=N. |last4=McConchie |first4=C. A. |date=2002 |title=Flowering and shoot elongation of lychee in eastern Australia |url=http://dx.doi.org/10.1071/ar01179 |journal=Australian Journal of Agricultural Research |volume=53 |issue=8 |pages=977 |doi=10.1071/ar01179 |issn=0004-9409}}</ref> Witch's broom deforms longan skin, and at times causes the plant to prematurely drop its fruit, similar to the ''[[Phytophthora palmivora]]''.<ref>{{Cite journal |last1=So |first1=Vera |last2=Zee |first2=S.-Y. |date=September 1972 |title=A New Virus of Longan (''Euphoria longana'' Lam.) in Hong Kong |url=http://dx.doi.org/10.1080/09670877209411804 |journal=PANS Pest Articles & News Summaries |volume=18 |issue=3 |pages=283–285 |doi=10.1080/09670877209411804 |issn=0030-7793}}</ref>

Another common disease that longan trees can carry is the aptly named ''longan decline'', which is largely prevalent in Thailand, with reports finding that it could affect up to 40% of longan trees alone.<ref name=":0">{{Cite book |url=http://dx.doi.org/10.1079/9780851996967.0000 |title=Litchi and longan: botany, production and uses |date=2005 |isbn=9780851996967 |editor-last=Menzel |editor-first=C. M. |doi=10.1079/9780851996967.0000 |editor2-last=Waite |editor2-first=G. K.}}</ref> Affected trees are more vulnerable to common tree pests and algae, and often bear low-quality fruit unworthy of yield.<ref name=":0" />

''Algal spot'' is another plant disease that can affect longan plants and trees. Common among tropical fruits, the disease mainly takes form as red-orange algae that can appear on a fruit-bearing tree's leaves or branches.<ref>{{Cite journal |last=Visarathanonth |first=N. |date=December 1990 |title=A Survey of Some Temperate Fruit Diseases in Thailand |url=http://dx.doi.org/10.17660/actahortic.1990.279.67 |journal=Acta Horticulturae |issue=279 |pages=609–618 |doi=10.17660/actahortic.1990.279.67 |issn=0567-7572}}</ref>''Algal spot'' on longan plants, like many other tropical fruits, is caused by ''[[Cephaleuros virescens]]''.<ref>{{Cite journal |last=Bache |first=Bryon |date=December 1994 |title=Compendium of Tropical Fruit Diseases, by R. C. Ploetz G. A. Zentmyer, W. T. Nishijima, K. G. Rohrbach & H. D. Ohr. viii + 88 pp. St Paul, Minnesota: American Phytopathological Society (1994). £30.00 (US) $37.00 (elsewhere) (paper back) {{text|ISBN}} 0 582 89054 162 0. |url=http://dx.doi.org/10.1017/s0021859600070520 |journal=The Journal of Agricultural Science |volume=123 |issue=3 |pages=419–420 |doi=10.1017/s0021859600070520 |issn=0021-8596}}</ref>

An oomycete disease that causes [[blight]] on leaves and foliage of a plant and affects the related lychee, ''Phytophthora palmivora'', can also appear on both longan plants and fruit,<ref name="Wang-et-al-20192">{{cite journal |last1=Wang |first1=Yan |last2=Tyler |first2=Brett M. |last3=Wang |first3=Yuanchao |date=2019-09-08 |title=Defense and Counterdefense During Plant-Pathogenic Oomycete Infection |journal=[[Annual Review of Microbiology]] |publisher=[[Annual Reviews (publisher)|Annual Reviews]] |volume=73 |issue=1 |pages=667–696 |doi=10.1146/annurev-micro-020518-120022 |issn=0066-4227 |pmid=31226025 |s2cid=195259901}}</ref> particularly in the Thailand region. When affecting longan, it can create brown spots on the fruit in an erratic fashion, and can also cause longan to drop prematurely from the plant. Early symptoms can also include a dark [[necrosis]] on the plant itself.<ref>{{Cite journal |last1=Sittigul |first1=C. |last2=Pota |first2=S. |last3=Visitpanich |first3=J. |last4=Nualbunruang |first4=P. |last5=Sookchaoy |first5=K. |date=January 2005 |title=The Brown Spot Disease of Longan in Thailand |url=http://dx.doi.org/10.17660/actahortic.2005.665.48 |journal=Acta Horticulturae |issue=665 |pages=389–394 |doi=10.17660/actahortic.2005.665.48 |issn=0567-7572}}</ref>

Stem-end rot is a disease common amongst litchi and longan, and causes browning and rot on the stem of the fruit. Longan also suffer from various decay-accelerating fungi.<ref name=":0" />

An oomycete disease that affects the related lychee, ''[[Phytophthora litchii]]'', also afflicts ''D.&nbsp;longan''.<ref name="Wang-et-al-20192" />