collar rot
{{short description|Disease of plants}}
{{Use dmy dates|date=October 2023}}
File:Lemon tree with phytophtora 02 - collar rot.jpg collar rot]]
Collar rot is a symptomatically described disease that is usually caused by any one of various fungal and oomycete plant pathogens. It is present where the pathogen causes a lesion localized at or about the collet between the stem and the root. The lesions develop around the stem eventually forming a "collar". Observationally, collar rot grades into "basal stem rot", and with some pathogens is the first phase of "basal stem rot" often followed by "root rot". Collar rot is most often observed in seedings grown in infected soil. The pathogens that cause collar rot may be species or genera specific. But generalist pathogens such as Agroathelia rolfsii (aka Sclerotium rolfsii or Athelia rolfsii) are known to attack over 200 different species.{{Cite journal|author1=Ahmad, Yasmin |author2=Mirza, M. Siddique |author3=Aslan, M. |year=1988|title=Collar Rot of Maize caused by Sclerotium rolfsii in Pakistan|journal=Pakistan Journal of Agricultural Research|volume=9|issue=4|pages=604–605|url=http://www.cabi.org/GARA/FullTextPDF/Pre2000/19901141977.pdf|archive-url=https://web.archive.org/web/20141102214500/http://www.cabi.org/GARA/FullTextPDF/Pre2000/19901141977.pdf|archive-date=2 November 2014|url-status=live}} While bacteria caused collar rot is not common, trees infected with Fire blight (Erwinia amylovora) may develop collar rot.{{Cite book|editor-last=Horst |editor-first=R. Kenneth|year=2008|title=Westcott's Plant Disease Handbook|edition=seventh|location=Dordrecht|publisher=Springer Verlag|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA105 105]|isbn=978-1-4020-5193-7}} Non-parasitic collar rot may be caused by winter damage.{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA720 720]}}
File:Calonectria collar rot of papaya.jpg collar rot of papaya]]
The symptomatically described disease Southern blight is often the first observed precursor of the collar rot caused by the fungus Agroathelia rolfsii. Causally known as Sclerotial blight,{{Cite web|author=Ames, Teresa |title=Sweetpotato Diagnotes: Sclerotial blight |publisher=Centre for Biological Information Technology (CBIT), The University of Queensland |url=http://keys.lucidcentral.org/keys/sweetpotato/key/Sweetpotato%20Diagnotes/Media/Html/TheProblems/DiseasesFungal/SclerotialBlight/Sclerotial%20blight.htm }} Agroathelia rolfsii survives in the soil as sclerotia, and in infected decomposing plant material as mycelia.{{Cite web |author1=Hartman, John |author2=Beale, Julie |author3=Bachi, Paul |title=Plant Pathology Fact Sheet: Root and Collar Rots of Tree Fruits |publisher=College of Agriculture, University of Kentucky |url=http://www2.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-FR-T-10.pdf |archive-url=https://web.archive.org/web/20081204190255/http://www.ca.uky.edu/agcollege/plantpathology/ext_files/PPFShtml/PPFS-FR-T-10.pdf |archive-date=4 December 2008 |url-status=dead |access-date=22 November 2014 }}
Collar rot that is caused by the oomycete Phytophthora is causally called Phytophthora collar rot, and is a common disease of fruit and nut trees,{{Cite web|author1=Thomson, Sherman V.|author2=Scott, C. Ockey|year=1998|title=Utah Pests Fact Sheet: Phytophthora Crown and Collar Rot|series=Utah Plant Disease Control No. 6|publisher=Utah State University Extension and Utah Plant Pest Diagnostic Lab (UPPDL)|url=http://utahpests.usu.edu/IPM/htm/fruits/fruit-insect-disease/root-crown-rot/|archive-url=https://web.archive.org/web/20120319093146/https://utahpests.usu.edu/IPM/htm/fruits/fruit-insect-disease/root-crown-rot/|archive-date=19 March 2012|url-status=dead|access-date=22 November 2014}} as well as other flowers{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA511 511]}} and crops.{{Cite book|author1=Erwin, D. C. |author2=Bartnicki-Garcia, S. |author3=Tsao, P. H. |year=1983|title=Phytophthora, its Biology, Taxonomy and Pathology|publisher=The American Phytopathological Society|location=St. Paul, Minnesota|isbn=978-0-89054-050-3}}{{Cite web|author=Gulya, Thomas J.|year=2012|title=Sunflower Diseases Remain Rare in California Seed Production Fields Compared to North Dakota |publisher=Plant Management Network|url=http://www.plantmanagementnetwork.org/pub/php/research/2012/sunflower/ |archive-url=https://web.archive.org/web/20141121215841/http://www.plantmanagementnetwork.org/pub/php/research/2012/sunflower/ |archive-date=21 November 2014|url-status=live|display-authors=etal}} Phytophthora species remain in the soil, as spores, and in infected plant tissue, as mycelia, so absent control measures (sterilization, toxic applications) the disease continues so long as susceptible plants are grown in that soil.{{Cite book|author=Agrios, George N.|year=1988|chapter=Phytophthora Foot, Crown, Collar, Stem, or Trunk Rots |title=Plant Pathology|edition=third|location=Burlington|publisher=Elsevier|pages=301–306|isbn=978-0-323-13969-4}}
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Hosts and agents
- In carnations (Dianthus caryophyllus) by Alternaria dianthi,{{Cite book|author=Horst, R. Kenneth|year=2013|title=Field Manual of Diseases on Garden and Greenhouse Flowers|location=Dordrecht|publisher=Springer Verlag|page=[https://books.google.com/books?id=ndhEAAAAQBAJ&pg=PA43 43]|isbn=978-94-007-6049-3|doi=10.1007/978-94-007-6049-3|s2cid=6747201}}
- In chili (Capsicum) by Phytophthora,{{Cite journal |author=Akter, M. K. |year=2007 |title=Pathogenicity of Phytophthora capsici and possibilities of its biological and chemical control |journal=Journal of Agroforestry and Environment |volume=1 |issue=2 |pages=81–84 |url=http://www.cseas.kyoto-u.ac.jp/brahmaputra/JAE/ASFBpdf/2.AFSB1(2)pdf/18.%20Nahar%201.pdf |archive-url=https://web.archive.org/web/20141121224346/http://www.cseas.kyoto-u.ac.jp/brahmaputra/JAE/ASFBpdf/2.AFSB1(2)pdf/18.%20Nahar%201.pdf |archive-date=21 November 2014 |url-status=dead|display-authors=etal |access-date=22 November 2014 }}
- In cinchona (Cinchona officinalis) by Phytophthora quininea,{{Cite book|author=Crandall, Bowen S.|year=1950|title=Cinchona root and collar rot in Peru and Bolivia|series=Circular no. 855|location=Washington, DC|publisher=United States Department of Agriculture|url=http://babel.hathitrust.org/cgi/pt?id=uiug.30112019276168}}
- In Chinese evergreens (Aglaonema) by Fusarium subgutinans,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA484 484]}}
- In coffee plants (Coffea) by Gibberella stilboides,{{Cite journal|author=Baker, Celia J.|year=1970|title=Coffee bark disease in Kenya|journal=Kenya Coffee|volume=35|issue=414|pages=226–228|url=http://www.cabdirect.org/abstracts/19710305083.html|url-access=subscription }}
- In dogwoods (genus Cornus) by Phytophthora cactorum where the disease is also called "crown canker",{{Cite web|author1=Snover-Clift, Karen |author2=Jensen-Tracey, Sandra|year=2011|title=Crown Canker of Dogwood, Phytophthora cactorum|publisher=Department of Plant Pathology and Plant-Microbe Biology, Cornell University|url=http://plantclinic.cornell.edu/factsheets/dogwoodcrowncanker.pdf |archive-url=https://web.archive.org/web/20120614211406/http://plantclinic.cornell.edu/factsheets/dogwoodcrowncanker.pdf |archive-date=14 June 2012|url-status=live}}{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA260 260]}}
- In eggplant/brinjal (Solanum melongena) by Sclerotinia sclerotiorum and Sclerotium rolfsii,{{Cite book|author=Reddy, P. Parvatha|year=2014|chapter=Solanaceous Vegetable Crops, 8.3.2 Collar Rot, Sclerotinia sclerotiorum, Sclerotium rolfsii|title=Plant Growth Promoting Rhizobacteria for Horticultural Crop Protection|location=New Delhi, India|publisher=Springer Verlag|pages=[https://books.google.com/books?id=sWeSBAAAQBAJ&pg=PA162 162–163]|isbn=978-81-322-1972-9|doi= 10.1007/978-81-322-1973-6|s2cid=44837424}}
- In elephant foot yams (Amorphophallus paeoniifolius) by Sclerotium rolfsii,{{Cite journal|author1=Pravi, V. |author2=Jeeva, M. L. |author3=Archana, P. V. |year=2014|title=Rapid and Sensitive Detection of Sclerotium rolfsii Associated with Collar Rot Disease of Amorphophallus paeoniifolius by Species-Specific Polymerase Chain Reaction Assay|journal=Molecular Biotechnology |volume=56|issue=9|pages=787–794 |pmid=24788585|doi=10.1007/s12033-014-9757-x |s2cid=10370740 }}
- In fruit and nut trees by a variety of pathogens including Sclerotium rolfsii, Alternaria{{Cite book|last=Khan |first=Aslam|year=2001|title=Plant Diseases|location=Delhi, India|publisher=Kalpaz Publications|pages=[https://books.google.com/books?id=IUyCPe1pTG8C&pg=PA99 99–102]|isbn=978-81-7835-052-3}} and Phytophthora,{{harvnb|Khan|2001|pages=[https://books.google.com/books?id=IUyCPe1pTG8C&pg=PA47 47–49]}}
- In groundnut/peanut (Arachis hypogaea) by Aspergillus niger which also causes wilt and crown rot,{{Cite journal|author1=Kishore, G. Krishna |author2=Pande, S. |author3=Podile, A. R. |year=2005|title=Biological control of collar rot disease with broad-spectrum antifungal bacteria associated with groundnut|journal=Canadian Journal of Microbiology|volume=51|issue=2|pages=123–132|doi=10.1139/w04-119|pmid=16091770 |s2cid=19249919 |url=http://podilerao.tripod.com/ramu11.pdf|archive-url=https://web.archive.org/web/20141031174327/http://podilerao.tripod.com/ramu11.pdf|archive-date=31 October 2014|url-status=live}} and by Lasiodiplodia theobromae,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA491 491]}}
- In hardwoods and conifers by Phytophthora cinnamomi,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA509 509]}}
- In maize (corn, Zea mays) by Sclerotium rolfsii,
- In papaya by Calonectria,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA463 463]}}
- In pines by both Phytophthora and Diplodia pinastri,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA475 475]}}
- In rhododendron, China aster, marigold, gloxinia and zinnia by Phytophthora cryptogea,
- In sunflowers by Sclerotium rolfsii,{{Cite journal|author1=Mizra, S. M. |author2=Khokhar, L. K.|year=1985|title=Occurrence of sunflower collar rot diseases caused by Sclerotium rolfsii in Pakistan|journal=Helia|volume=8 |pages=41–43}}{{Cite book|author1=Gulya, Thomas |author2=Rashid, Khalid Y. |author3=Masirevic, Stevan M. |year=1997|chapter=Sunflower diseases|editor=Schneiter, Albert A.|title=Sunflower technology and production|location=Madison, Wisconsin|publisher=Soil Science Society of America|pages=263–379|isbn=978-0-89118-227-6|doi=10.2134/agronmonogr35.c6}} and by Phytophthora cryptogea.
- In sweet potatoes (Ipomoea batatas) by Sclerotium rolfsii,
- In tobacco by Sclerotinia sclerotiorum.{{Cite web|author=Virginia Polytechnic Institute|date=31 December 2008|title=Disease Management Research for Virginia Tobacco|publisher=Research, Education & Economics Information System, United States Department of Agriculture|url=http://www.reeis.usda.gov/web/crisprojectpages/0198905-disease-management-research-for-virginia-tobacco.html}}
- In tomatoes (Solanum lycopersicum) by Alternaria solani,{{harvnb|Horst|2008|page=[https://books.google.com/books?id=M6WLVNWDQ-QC&pg=PA456 456]}}{{Cite journal|author1=Maiero, Marisa |author2=Ng, Timothy J. |author3=Barksdale, Thomas H. |year=1990|title=Inheritance of Collar Rot Resistance in the Tomato Breeding Lines C 1943 and NC EBR-2|journal=Phytopathology|volume=80|issue=12|pages=1365–1368|url=http://www.apsnet.org/publications/phytopathology/backissues/Documents/1990Articles/Phyto80n12_1365.PDF|doi=10.1094/phyto-80-1365|bibcode=1990PhPat..80.1365M }}
Related diseases
- Rootstock blightSymptoms of rootstock blight can be confused with Phytophthora collar rot. {{Cite journal|author=Johnson, Kenneth B.|year=2005|title=Fire blight of apple and pear|journal=The Plant Health Instructor |doi=10.1094/PHI-I-2000-0726-01 |url=http://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/FireBlight.aspx |archive-url=https://web.archive.org/web/20120203212538/http://www.apsnet.org/edcenter/intropp/lessons/prokaryotes/Pages/FireBlight.aspx |archive-date=3 February 2012|url-status=live|url-access=subscription}}
- Stem rot