Botryotinia porri (Botrytis rot of garlic)
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Means of Movement and Dispersal
- Plant Trade
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Botryotinia porri (H.J.F. Beyma) Whetzel
Preferred Common Name
- Botrytis rot of garlic
Other Scientific Names
- Botrytis porri N.F. Buchw.
- Sclerotinia porri H.J.F. Beyma
International Common Names
- English: Botrytis rot of leek; mycelial: onion neck rot; neck rot of onion; seedling damping-off of onion
- BOTTPO (Botryotinia porri)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Fungi
- Phylum: Ascomycota
- Subphylum: Pezizomycotina
- Class: Leotiomycetes
- Subclass: Leotiomycetidae
- Order: Helotiales
- Family: Sclerotiniaceae
- Genus: Botryotinia
- Species: Botryotinia porri
Notes on Taxonomy and NomenclatureTop of page
There has been a certain confusion in the literature about the species of Botryotinia and Botrytis on Allium (Lacy and Lorbeer, 1995). Moore (1959) cites Cronshey (1947) as considering that the onion pathogen Botrytis byssoidea is the anamorph of Botryotinia porri. On this basis, Botrytis porri would be a synonym of B. byssoidea. Smith et al. (1988) have followed this interpretation. However, most authors do not refer to any teleomorph of B. byssoidea, which is treated as though it were mitosporic. In fact, the teleomorph of B. byssoidea has been described in Japan as Botryotinia allii (Yamamoto et al., 1956). This is accepted by Jarvis (1980) and Farr et al. (1989). In particular, Hennebert (1973) clearly separates Botrytis porri from Botrytis byssoidea. The current authoritative view is thus that there are two distinct species, Botryotinia allii (with anamorph Botrytis byssoidea) and Botryotinia porri (with anamorph Botrytis porri), besides the third, Botryotinia squamosa (with anamorph Botrytis squamosa). Lacy and Lorbeer (1995) have suggested further that B. byssoidea may be conspecific with Botrytis allii (which has no known teleomorph). The situation needs further clarification. In any case, the polyphagous Botryotinia fuckeliana (anamorph Botrytis cinerea) is also found on Allium. Cases of 'Botrytis' on Allium may often be inadequately identified.
DescriptionTop of page
According to Presly (1985), B. porri does not abundantly produce conidia in culture (unlike B. allii). Like B. byssoidea, its mycelium is white and fluffy but it readily produces sclerotia, unlike B. byssoidea. B. squamosa produces smaller sclerotia on white ropy mycelium.
DistributionTop of page
The available information on the geographical distribution of B. porri appears incomplete. It has been recorded in several European countries on leeks, and in others on garlic but it seems likely that the fungus occurs more widely in Europe in leek and garlic-producing countries. Similarly, it seems likely that the species occurs more widely in North America than published records indicate. Apart from New Zealand, there are no specific records from other parts of the world, though the confusion with Botryotinia allii (see Notes on Taxonomy and Nomenclature) may have led to some misattribution of records. In many countries, cases of B. porri may readily have been misidentified as other species of Botrytis.
Specimens of B. porri held at CABI Bioscience (Egham, UK) are also cited in the distribution table (IMI Herbarium, undated).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.Last updated: 17 Feb 2021
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Germany||Present||Original citation: Bottcher and Pohle (1991)|
|United Kingdom||Present, Widespread|
|United States||Present, Localized|
|Australia||Present||Present based on regional distribution.|
|-New South Wales||Present|
Risk of IntroductionTop of page
Hosts/Species AffectedTop of page
Host Plants and Other Plants AffectedTop of page
Growth StagesTop of page
SymptomsTop of page
List of Symptoms/SignsTop of page
|Vegetative organs / dry rot|
|Vegetative organs / internal rotting or discoloration|
|Vegetative organs / mould growth|
Biology and EcologyTop of page
Post-harvest damage arises from the spread of lesions formed in the field. In stored leeks, the fungus does not spread at storage temperatures of -1 to 0°C, but lesions expand at 5°C or above.
Means of Movement and DispersalTop of page
The fungus spreads by wind or rain dispersal of ascospores and conidia.
Crowe et al. (1995) mention that there are unconfirmed reports that B. porri may be seed-borne. Since B. porri does not apparently infect the above-ground parts of the plant, and is not known to produce the kind of latent infection which characterizes the seed-borne B. allii, such seed-borne transmission seems implausible.
Movement in trade
B. porri may be spread by planting material (bulbs of garlic, possibly young seedlings of leek). Internationally, it could also be introduced into new areas with garlic bulbs or leeks for consumption, although it is relatively unlikely that diseased material should enter international trade because of its obvious poor quality.
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Bulbs/Tubers/Corms/Rhizomes||spores||Yes||Yes||Pest or symptoms usually visible to the naked eye|
|Plant parts not known to carry the pest in trade/transport|
|Fruits (inc. pods)|
|Growing medium accompanying plants|
|Stems (above ground)/Shoots/Trunks/Branches|
|True seeds (inc. grain)|
ImpactTop of page
Detection and InspectionTop of page
Similarities to Other Species/ConditionsTop of page
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.Good hygiene will prevent the persistence of sclerotia or infected crop debris in the soil. Agricultural practices that would create cool moist conditions in the upper layers of the soil should be avoided, in particular in relation to irrigation. No particular chemical control is recommended. In store, leeks should be kept at a sufficiently low temperature. Alternatively, increasing the carbon dioxide content of the storage atmosphere, and decreasing the oxygen content, will prevent development of the fungus (Hoftun, 1978).
ReferencesTop of page
Cedeño L, Carrero C, Quintero K, Segovia P, 2003. Botrytis porri, causal agent of neck rot of garlic in Mérida, Venezuela. (Botrytis porri, Causante de pudrición en el cuello del ajo en Mérida, Venezuela.) Interciencia, 28(5):273-275.
Cronshey JFH, 1947. Sclerotinia porri on Allium spp. in England. Nature (London), 160:798.
Crowe F, Mohan SK, Schwartz HF, 1995. Botrytis rot of garlic. In: Schwartz HF, Mohan SK, eds. Compendium of Onion and Garlic Diseases. St Paul, USA: American Phytopathological Society, 19-20.
IMI Herbarium, undated. Herbarium specimen. International Mycological Institute (now CABI Bioscience) Herbarium. Egham, UK: CABI Bioscience.
IPPC, 2006. IPP Report No. CL-2/1. Rome, Italy: FAO.
Jarvis WR, 1980. Taxonomy. In: Coley-Smith JR, Verhoeff K, Jarvis WR, eds. The Biology of Botrytis. London, UK: Academic Press, 1-18.
Lacy ML, Lorbeer JW, 1995. Botrytis neck rot. In: Schwartz HF, Mohan SK, eds. Compendium of Onion and Garlic Diseases. St Paul, USA: American Phytopathological Society, 18-19.
Mirzaei S, Goltapeh EM, Shams-Bakhsh M, Safaie N, 2008. Identification of Botrytis spp. on plants grown in Iran. Journal of Phytopathology, 156(1):21-28. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1439-0434.2007.01317.x
Moore WC, 1959. British parasitic fungi. Cambridge, UK: Cambridge University Press, 430 pp.
Roed H, 1952. Botryotinia porri on Allium porrum in Norway. Acta Agriculturae Scandinavica, 2;232-241.
Somerville PA, Hall DH, Greathead AS, 1984. Dry rot of garlic caused by Botrytis porri. Phytopathology, 74:829.
Yamamoto, W. , Oyasu, N. , Iwasaki, A. , 1956. Studies on the leaf blight disease of Allram spp. caused by Botrytis and Botryotinia fungi., L. Sci. Rep. Hyogo Univ. Agric. Ser. Agric. Biol., 2(2):17-22
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Cedeño L, Carrero C, Quintero K, Segovia P, 2003. Botrytis porri, causal agent of neck rot of garlic in Mérida, Venezuela. (Botrytis porri, Causante de pudrición en el cuello del ajo en Mérida, Venezuela.). Interciencia. 28 (5), 273-275.
Crowe F, Mohan SK, Schwartz HF, 1995. Botrytis rot of garlic. In: Compendium of Onion and Garlic Diseases, [ed. by Schwartz HF, Mohan SK]. St Paul, USA: American Phytopathological Society. 19-20.
Herb IMI, Undated. Specimen record from the collection in the Herb IMI Database., Kew, UK: Royal Botanic Gardens, Kew. http://www.herbimi.info/herbimi/home.htm
Hoftun H, 1978. Storage of leeks. IV. Effects of temperatures and atmospheric compositions on growth of Botrytis porri. (Lagring av purre. IV. Verknad av temperaturar og luftsamansetnader pa vekst av Botrytis porri.). Meldinger fra Norges Landbrukshoegskole. 57 (39), 1-17.
IPPC, 2006. IPP Report No. CL-2/1., Rome, Italy: FAO.
Mirzaei S, Goltapeh E M, Shams-Bakhsh M, Safaie N, 2008. Identification of Botrytis spp. on plants grown in Iran. Journal of Phytopathology. 156 (1), 21-28. http://www.blackwell-synergy.com/doi/abs/10.1111/j.1439-0434.2007.01317.x
Somerville PA, Hall DH, Greathead AS, 1984. Dry rot of garlic caused by Botrytis porri. In: Phytopathology, 74 829.
Zhang J, Li G Q, Jiang D H, 2009. First report of garlic leaf blight caused by Botrytis porri in China. Plant Disease. 93 (11), 1216. http://apsjournals.apsnet.org/loi/pdis DOI:10.1094/PDIS-93-11-1216B
Distribution MapsTop of page
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