Sooty mold
Sooty mold(also spelledsooty mould) is a collective term for differentAscomycetefungi, which includes many genera, commonlyCladosporiumandAlternaria.[1][2]It grows on plants and their fruit, but also environmental objects, like fences, garden furniture, stones, and even cars. The mold benefits from either a sugaryexudateproduced by the plant or fruit, orhoneydew-secreting insects or sap suckers the plant may be infested by.
Sooty mold itself does little if any harm to the plant. Treatment is indicated when the mold is combined with insect infestation.
Description
[edit]Sooty mold is a collective, self-descriptive term for a number of different fungi; it is a black, powdery coating adhering to plants and their fruit or environmental objects.
Biology
[edit]The ecology of the different species, their interactions, relationship to the host are little understood. A chance observation of aMicrocyclosporatardicrescensinhibiting the growth of the fruit pathogenColletotrichum fioriniaein dual culture tests, yielded trichothecolone acetate and its (S)-7-hydroxy derivative as active principles for the interaction betweenM. tardicrescensandC. fioriniae.[3]
Common genera of sooty mold fungi found areAethaloderma,Capnodium,Cladosporium,Euantennaria,Scorias,andTrichomerium.[4]
Other genera causing sooty molds areAlternaria,Cladosporium,Aureobasidium,Antennariella,Limacinula,Scorias,Meliola,andCapnodium.[citation needed]
Sooty mold grows particularly well on plants that produce a sugary exudate, if they are infested byhoneydewsecreting insects such asaphids,scalesand thewhitefly,or when infested by insects that suck sap from the host plant.[5]
Plants commonly affected
[edit]Sooty mold is commonly seen on the leaves of ornamental plants such asazaleas,gardenias,camellias,crepe myrtles,Mangiferaandlaurels.Karukais affected by sooty mold caused byMeliola juttingii.[6]Plants located underpecanor hickory trees are particularly susceptible to sooty mold, because honeydew-secreting insects often inhabit these trees. The honeydew can rain down on neighboring and understory plants. Occasionallycitrusmay exude sweet sticky secretions and sooty molds can grow on these.[5]
Effect
[edit]The fungus itself does little harm to the plant; it merely blocks sunlight, and very rarely may stunt a plant's growth and yellow its foliage. Thus, sooty mold is essentially a cosmetic problem in the garden, as it is unsightly and can coat most of a plant in a matter of days or weeks.
Control
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The simplest form of non-chemical control is to wipe and wash affected plant parts with lukewarm water and soap, insecticidal soap or dish soap, one tablespoon per gallon of water; strong soaps or detergents may damage the plant. This can also be sprayed if the plant is large but is much less effective than when combined with physical removal. After allowing the soap to sit for a while the sooty mold is rinsed off with a hose/ water. Sooty mold will regrow, unless the underlying reason for its growth is eliminated.
Chemical control of sooty mold itself is not needed. If sap-sucking pests are responsible for the honeydew on which the mold is growing, there are several options:
Using formulations ofneem oil,which is an organic broad spectrum pesticide, insecticide, fungicide and miticide controls mites and insects such as whitefly, aphid, scale, and mealy bugs, and additional fungus diseases like black spot, rust, mildew, and scab. Neem oil can be used on house plants, flowers, vegetables, trees, shrubs and fruit indoors and outdoors. Neem oil is biodegradable and has not been shown to be toxic to mammals, birds, bees, earthworms, or beneficial insects.[7]
Synthetic insecticides such as the organophosphatesacephate(orthene),malathion,ordiazinoncan be used in severe cases but read the labels for approved crops and the number of days to wait to harvest.
See also
[edit]References
[edit]- ^Gleason, Mark L.; Zhang, Rong; Batzer, Jean C.; Sun, Guangyu (2019)."Stealth Pathogens: The Sooty Blotch and Flyspeck Fungal Complex".Annual Review of Phytopathology.57(1): 135–164.doi:10.1146/annurev-phyto-082718-100237.ISSN0066-4286.PMID31150591.S2CID172137916.
- ^Gleason, Mark L.; Batzer, Jean C.; Sun, Guangyu; Zhang, Rong; Arias, Maria M. Díaz; Sutton, Turner B.; Crous, Pedro W.; Ivanović, Milan; McManus, Patricia S.; Cooley, Daniel R.; Mayr, Ulrich (2011)."A New View of Sooty Blotch and Flyspeck".Plant Disease.95(4): 368–383.doi:10.1094/PDIS-08-10-0590.hdl:20.500.11755/2e0839d7-fe09-4cd8-92e4-7eb5240120dc.ISSN0191-2917.PMID30743360.
- ^Surup, Frank; Medjedović, Ajda; Szczygielski, Michael; Schroers, Hans-Josef; Stadler, Marc (2014)."Production of Trichothecenes by the Apple Sooty Blotch Fungus Microcyclospora tardicrescens".Journal of Agricultural and Food Chemistry.62(16): 3525–3530.doi:10.1021/jf500153d.ISSN0021-8561.PMID24697667.
- ^Gillman, Dan (6 March 2015)."Sooty Mold".Center for Agriculture, Food, and the Environment.University of Massachusetts Amherst.Retrieved6 November2021.
- ^ab"Sooty moulds".Royal Horticultural Society.Retrieved16 July2015.
- ^French, Bruce R.(1982).Growing food in the Southern Highlands Province of Papua New Guinea(PDF).AFTSEMU (Agricultural Field Trials, Surveys, Evaluation and Monitoring Unit) of the World Bank funded project in the Southern Highlands of Papua New Guinea. pp. 64–71.Retrieved20 September2018.
- ^"U.S. EPA, Pesticide Product Label, NEEM OIL 70%"(PDF).Environmental Protection Agency (EPA).December 2, 2005.
Further reading
[edit]- Chomnunti P.; Hongsanan S.; Aguirre-Hudson B.; Tian Q.; Peršoh D.; Dhami M. K.; Alias A. S.; Xu J.; Liu X.; Stadler M.; Hyde K. D. (2014). "The sooty moulds".Fungal Diversity.66(1): 1–36.doi:10.1007/s13225-014-0278-5.S2CID3344487.
External links
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Media related toSooty moldat Wikimedia Commons
