View source for Cowpea

{{Short description|Species of plant}}
{{Good article}}
{{Speciesbox
|name = Cowpea
|image = Lobia.jpg
|image_caption = Cowpeas
|genus = Vigna
|species = unguiculata
|authority = ([[Carl Linnaeus|L.]]) [[Wilhelm Gerhard Walpers|Walp.]]
|synonyms = 
{{hidden begin|toggle=left|title=List}}
* ''Dolichos biflorus'' L.
* ''Dolichos catiang'' L.
* ''Dolichos catjang'' Burm.f. nom. illeg.
* ''Dolichos catjang'' L.
* ''Dolichos hastifolius'' Schnizl.
* ''Dolichos lubia'' Forssk.
* ''Dolichos melanophthalamus'' DC.
* ''Dolichos monachalis'' Brot.
* ''Dolichos obliquifolius'' Schnizl.
* ''Dolichos sesquipedalis'' L.
* ''Dolichos sinensis'' Forssk. nom. illeg.
* ''Dolichos sinensis'' L.
* ''Dolichos sphaerospermus'' (L.) DC.
* ''Dolichos tranquebaricus'' Jacq.
* ''Dolichos unguiculata'' L.
* ''Dolichos unguiculatus'' Thunb.
* ''Liebrechtsia scabra'' De Wild.
* ''Phaseolus cylindricus'' L.
* ''Phaseolus sphaerospermus'' L.
* ''Phaseolus unguiculatus'' (L.) Piper
* ''Scytalis hispida'' E.Mey.
* ''Scytalis protracta'' E.Mey.
* ''Scytalis tenuis'' E.Mey.
* ''Vigna alba'' (G.Don) Baker f.
* ''Vigna angustifoliolata'' Verdc.
* ''Vigna baoulensis'' A.Chev.
* ''Vigna catjang'' (Burm.f.) Walp.
* ''Vigna coerulea'' Baker
* ''Vigna dekindtiana'' Harms
* ''Vigna hispida'' (E.Mey.) Walp.
* ''Vigna huillensis'' Baker
* ''Vigna malosana'' Baker
* ''Vigna protracta'' (E.Mey.) Walp.
* ''Vigna pubescens'' R.Wilczek
* ''Vigna rhomboidea'' Burtt Davy
* ''Vigna scabra'' (De Wild.) T.Durand & H.Durand
* ''Vigna scabrida'' Burtt Davy
* ''Vigna sesquipedalis'' (L.) F. Agcaoili nom. illeg.
* ''Vigna sesquipedalis'' (L.) Fruwirth
* ''Vigna sinensis'' (L.) Endl. ex Hassk. nom. illeg.
* ''Vigna sinensis'' (L.) Savi ex Hausskn.
* ''Vigna tenuis'' (E.Mey.) F.Dietr.
* ''Vigna triloba'' var. ''stenophylla'' Harv.
{{hidden end}}
|synonyms_ref = <ref>{{cite web|url=http://www.theplantlist.org/tpl/search?q=Vigna+unguiculata|title=The Plant List: A Working List of All Plant Species}}</ref><ref>{{cite web|url=http://www.ipni.org/ipni/advPlantNameSearch.do;jsessionid=C40C8CF0B8312AA716FD90000559E9F5?find_family=&find_genus=Vigna&find_species=sinensis&find_infrafamily=&find_infragenus=&find_infraspecies=&find_authorAbbrev=&find_includePublicationAuthors=on&find_includePublicationAuthors=off&find_includeBasionymAuthors=on&find_includeBasionymAuthors=off&find_publicationTitle=&find_isAPNIRecord=on&find_isAPNIRecord=false&find_isGCIRecord=on&find_isGCIRecord=false&find_isIKRecord=on&find_isIKRecord=false&find_rankToReturn=all&output_format=normal&find_sortByFamily=on&find_sortByFamily=off&query_type=by_query&back_page=plantsearch|title=International Plant Names Index, entry for ''Vigna sinensis''}}</ref><ref>{{cite web|url=http://www.ipni.org/ipni/idPublicationSearch.do?id=20159-2&back_page=%2Fipni%2FeditAdvPublicationSearch.do%3Ffind_title%3Dplantae%2Bjavan*%26find_abbreviation%3D%26output_format%3Dnormal|title=International Plant Names Index, entry for Pl. Jav. Rar. (Hasskarl)}}</ref>
}}

The '''cowpea''' (''Vigna unguiculata'') is an [[Annual plant|annual]] [[Herbaceous plant|herbaceous]] [[legume]] from the genus ''[[Vigna]]''. Its tolerance for sandy soil and low rainfall have made it an important [[crop]] in the [[Semi-arid climate|semiarid]] regions across [[Africa]] and [[Asia]]. It requires very few inputs, as the plant's [[root nodule]]s are able to [[Nitrogen fixation|fix atmospheric nitrogen]], making it a valuable crop for resource-poor farmers and well-suited to [[intercropping]] with other crops. The whole plant is used as [[forage]] for animals, with its use as cattle feed likely responsible for its name.

Four subspecies of cowpeas are recognised, of which three are cultivated. A high level of [[Morphology (biology)|morphological]] diversity is found within the species with large variations in the size, shape, and structure of the plant. Cowpeas can be erect, semierect ([[Trailing plant|trailing]]), or [[Climbing plant|climbing]]. The crop is mainly grown for its seeds, which are high in [[Protein (nutrient)|protein]], although the leaves and immature seed pods can also be consumed.

Cowpeas were [[Domestication|domesticated]] in Africa<ref name="postharvest"/> and are one of the oldest crops to be farmed. A second domestication event probably occurred in Asia, before they spread into Europe and the Americas. The seeds are usually cooked and made into stews and curries, or ground into flour or paste.

Most cowpeas are grown on the African continent, particularly in [[Nigeria]] and [[Niger]], which account for 66% of world production. A 1997 estimate suggests that cowpeas are cultivated on {{convert|12.5|ha||disp=preunit|million }} of land, have a worldwide production of 3 million tonnes and are consumed by 200 million people on a daily basis.<ref name="Singh 1997" /> Insect infestation is a major constraint to the production of cowpea, sometimes causing over 90% loss in yield.<ref name=":3" /> The legume pod borer ''[[Maruca vitrata]]'' is the main preharvest pest of the cowpea and the cowpea weevil ''[[Callosobruchus maculatus]]'' the main postharvest pest.

== Taxonomy and etymology ==
[[File:BlackEyedPeas.JPG|alt=A group of brown kidney-shaped peas, a black spot is visible on some of them.|thumb|[[Black-eyed pea]]s, a common name for a cowpea cultivar, are named due to the presence of a distinctive black spot on their [[Hilum (biology)|hilum]].]]
''Vigna unguiculata'' is a member of the ''[[Vigna]]'' (peas and beans) genus. ''Unguiculata'' is Latin for "with a small claw", which reflects the small stalks on the flower petals.<ref name="Small 2009">{{Cite book |url=https://books.google.com/books?id=nyWY_YkV7qAC&q=%27%27Vigna+unguiculata%27%27++%27%27Vigna%27%27+small+claw&pg=PA104 |title=Top 100 Food Plants |last=Small |first=Ernest |year=2009 |publisher=NRC Research Press |isbn=978-0-660-19858-3 |page=104}}</ref> Common names for cultivated cowpeas include black-eye pea,<ref>{{Cite web|title=Are black-eyed peas really peas?|url=https://www.loc.gov/item/are-black-eyed-peas-really-peas/|website=Library of Congress|access-date=2020-05-16}}</ref> southern pea,<ref>{{Cite web|title=Southern Peas - Gardening Solutions - University of Florida, Institute of Food and Agricultural Sciences|url=https://gardeningsolutions.ifas.ufl.edu/plants/edibles/vegetables/southern-peas.html|website=gardeningsolutions.ifas.ufl.edu|access-date=2020-05-16}}</ref> niebe<ref>{{Cite web|title=Niebe: A Food of Choice to Combat Hunger|url=https://www.icco-cooperation.org/en/news/niebe-a-food-of-choice-to-combat-hunger/|website=ICCO EN|language=en-US|access-date=2020-05-16|archive-date=2020-07-28|archive-url=https://web.archive.org/web/20200728233844/https://www.icco-cooperation.org/en/news/niebe-a-food-of-choice-to-combat-hunger/|url-status=dead}}</ref> (alternatively ñebbe),<ref>{{Cite web|title=ñebbe - Wiktionary|url=https://en.m.wiktionary.org/wiki/%C3%B1ebbe|website=en.m.wiktionary.org|access-date=2020-05-16}}</ref> and crowder pea.<ref>{{Cite web|title=Crowder pea|url=https://www.thefreedictionary.com/Crowder+pea|website=TheFreeDictionary.com|access-date=2020-05-16}}</ref> All cultivated cowpeas are found within the universally accepted ''V. unguiculata'' subspecies ''unguiculata'' classification, which is then commonly divided into four [[cultivar]] groups: ''unguiculata'', ''biflora'', ''sesquipedalis'', and ''textilis.''<ref name="Padulosil 1997">{{cite book|chapter-url=http://pdf.usaid.gov/pdf_docs/pnacb024.pdf|title=Advances in Cowpea Research|first1=S.|last1=Padulosil|first2=N. Q.|last2=Ng|editor2-last=Mohan|editor2-first=D. R.|editor3-last=Dashiell|editor3-first=K. E.|editor4-last=Jackai|editor4-first=L. E. N.|publisher=[[International Institute of Tropical Agriculture]] and Japan International Research Center for Agricultural Sciences|year=1997|location=Ibadan, Nigeria|chapter=Origin, taxonomy, and morphology of ''Vigna unguiculata'' (L.) Walp.|editor1-last=Singh|editor1-first=B. B.}}</ref><ref name="Perrino 1993" /> The classification of the wild relatives within ''V. unguiculata'' is more complicated, with over 20 different names having been used and between 3 and 10 subgroups described.<ref name="Padulosil 1997" /><ref>{{cite journal |journal=Theoretical and Applied Genetics |year=1999| volume=98 |issue=6–7 |pages=1104–1119 |title=Genetic relationships among subspecies of Vigna unguiculata (L.) Walp. based on allozyme variation |first=R. S. |last=Pasquet |doi=10.1007/s001220051174|s2cid=38331950}}</ref> The original subgroups of ''stenophylla'', ''dekindtiana'', and ''tenuis ''appear to be common in all taxonomic treatments, while the variations ''pubescens ''and'' protractor'' were raised to subspecies level by a 1993 characterisation.<ref name="Padulosil 1997" /><ref>This appears to be one of the latest taxonomical classifications</ref>

[[File:Sea Island red peas.jpg|thumb|[[Sea Island red pea]] a cultivar of cowpea grown by the [[Gullah people]] on the [[Sea islands]].]]

The first written reference of the word 'cowpea' appeared in 1798 in the United States.<ref name="Small 2009" /> The name was most likely acquired due to their use as a [[fodder]] crop for cows.<ref name="Tinko 2007">{{cite book|last1=Timko|first1=M. P.|last2=Ehlers|first2=J. D.|last3=Roberts|first3=P.A.|year=2007 |chapter=Cowpea|title=Pulses, Sugar and Tuber Crops, Genome Mapping and Molecular Breeding in Plants|editor1-last=Kole|editor1-first=C.|volume=3|publisher=Springer-Verlag|location=Berlin, Heidelberg|pages=49–67|url-status=dead|archive-date=1 June 2010|chapter-url=http://www.faculty.virginia.edu/timko/pdfs/Timko%20et%20al%20%282007%29%20Chapter%203%20Cowpea.pdf|archive-url=https://web.archive.org/web/20100601172132/http://www.faculty.virginia.edu/timko/pdfs/Timko%20et%20al%20(2007)%20Chapter%203%20Cowpea.pdf}}</ref> Black-eyed pea, a common name used for the ''unguiculata'' cultivar group, describes the presence of a distinctive black spot at the [[Hilum (biology)|hilum]] of the seed. Black-eyed peas were first introduced to the southern states in the United States and some early varieties had peas squashed closely together in their pods, leading to the other common names of southern pea and crowder pea.<ref name="Small 2009" /> 

The ''sesquipedalis'' subspecies arrived in the United States via Asia. It is characterised by unusually long pods, leading to the Latin name (''sesquipedalis'' means "foot and a half long") and the common names of yardlong bean, asparagus bean, and Chinese long-bean.<ref>{{cite book|title = Foods & Nutrition Encyclopedia|last1 = Ensminger|first1 = Marion|publisher = CRC Press|year = 1993|isbn = 978-0-8493-8980-1|location = Florida|page = 2363|last2 = Ensminger|first2 = Audrey}}</ref>

[[File:Vigna unguiculata varieties.jpg|thumb|A selection of different cowpea cultivars displayed in a wooden bowl.]]

{| class="wikitable"
|+Common names of ''Vigna unguiculata'' ''unguiculata'' cultivar groups
!
Group
!
Common name
|-
| Unguiculata
| [[black-eyed pea]], crowder-pea, southern pea, niebe, ñebbe
|-
| Biflora
| [[catjang]], sow-pea
|-
| Sesquipedalis
| [[yardlong bean]], asparagus bean, Chinese long-bean
|-
| Textilis
| wild cowpea, African cowpea, Ethiopian cowpea
|}

== Description ==
A large [[Morphology (biology)|morphological]] diversity is found within the crop, and the growth conditions and grower preferences for each variety vary from region to region.<ref name="Padulosil 1997" /> However, as the plant is primarily [[Self-pollination|self-pollinating]], its [[genetic diversity]] within varieties is relatively low.<ref>{{Cite journal|last1=Egbadzor|first1=Kenneth F|last2=Ofori|first2=Kwadwo|last3=Yeboah|first3=Martin|last4=Aboagye|first4=Lawrence M|last5=Opoku-Agyeman|first5=Michael O|last6=Danquah|first6=Eric Y|last7=Offei|first7=Samuel K|year=2014|title=Diversity in 113 cowpea [''Vigna unguiculata'' (L) Walp] accessions assessed with 458 SNP markers|journal=SpringerPlus|volume=3|page=541|doi=10.1186/2193-1801-3-541|issn=2193-1801|pmc=4190189|pmid=25332852 |doi-access=free }}</ref> Cowpeas can either be short and bushy (as short as {{convert|20|cm|in|0|abbr=on|disp=or}}) or act like a vine by climbing supports or trailing along the ground (to a height of {{convert|2|m|ftin|abbr=on|disp=or}}).<ref name=":7">{{Cite web|url=https://plants.usda.gov/plantguide/pdf/pg_viun.pdf|title=Plant guide for cowpea (''Vigna unguiculata'').|last=Sheahan|first=C. M.|date=2012|website=USDA-Natural Resources Conservation Service, Cape May Plant Materials Center, Cape May, NJ}}</ref><ref name=":17">{{Cite book|chapter-url=https://www.nap.edu/read/11763/chapter/7#115|title=Lost Crops of Africa: Volume II: Vegetables|last=National Research Council|publisher=The National Academies Press|year=2006|isbn=978-0-309-10333-6|location=Washington DC|pages=104–117|language=en|chapter=Cowpea|doi=10.17226/11763}}</ref> The [[taproot]] can penetrate to a depth of {{convert|2.4|m|ftin|abbr=on}} after eight weeks.<ref name=":8">{{Cite book|chapter-url=https://www.hort.purdue.edu/newcrop/afcm/cowpea.html|chapter=Cowpea|last1=Davis|first1=D. W.|last2=Oelke|first2=E. A.|website=www.hort.purdue.edu|publisher= University of Wisconsin-Extension, Cooperative Extension|year=1991|access-date=2017-04-13|last3=Oplinger|first3=E. S.|last4=Doll|first4=J. D.|last5=Hanson|first5=C.V.|last6=Putnam|first6=D. H.|title=Alternative Field Crops Manual}}</ref>

The size and shape of the leaves vary greatly, making this an important feature for classifying and distinguishing cowpea varieties.<ref>{{Cite journal|last1=Pottorff|first1=Marti|last2=Ehlers|first2=Jeffrey D.|last3=Fatokun|first3=Christian|last4=Roberts|first4=Philip A.|last5=Close|first5=Timothy J.|date=2012|title=Leaf morphology in Cowpea [''Vigna unguiculata'' (L.) Walp]: QTL analysis, physical mapping and identifying a candidate gene using synteny with model legume species|journal=BMC Genomics|volume=13|pages=234|doi=10.1186/1471-2164-13-234|issn=1471-2164|pmc=3431217|pmid=22691139 |doi-access=free }}</ref> Another distinguishing feature of cowpeas is the long {{convert|20|-|50|cm|in|0|abbr=on}} [[Peduncle (botany)|peduncles]], which hold the flowers and seed pods. One peduncle can support four or more seed pods.<ref name=":8" /> Flower colour varies through different shades of purple, pink, yellow, and white and blue.<ref name=":17" />

Seeds and seed pods from wild cowpeas are very small,<ref name=":8" /> while cultivated varieties can have pods between {{convert|10|and|110|cm|in|0|abbr=on}} long.<ref>{{Cite journal|last=Rawal|first=Kanti M.|date=1975|title=Natural hybridization among wild, weedy and cultivated ''Vigna unguiculata'' (L.) Walp.|journal=Euphytica|language=en|volume=24|issue=3|pages=699–707|doi=10.1007/BF00132908|bibcode=1975Euphy..24..699R |s2cid=45539164|issn=0014-2336}}</ref> A pod can contain six to 13 seeds that are usually kidney-shaped, although the seeds become more spherical the more restricted they are within the pod.<ref name=":7" /><ref name=":8" /> Their texture and colour are very diverse. They can have a smooth or rough coat and be speckled, mottled, or blotchy. Colours include white, cream, green, red, brown, and black, or various combinations.<ref name=":8" />

== History ==

Compared to most other important crops, little is known about the [[domestication]], dispersal, and cultivation history of the cowpea.<ref name=":9">{{Cite journal|last1=Xiong|first1=Haizheng|last2=Shi|first2=Ainong|last3=Mou|first3=Beiquan|last4=Qin|first4=Jun|last5=Motes|first5=Dennis|last6=Lu|first6=Weiguo|last7=Ma|first7=Jianbing|last8=Weng|first8=Yuejin|last9=Yang|first9=Wei|date=2016|title=Genetic Diversity and Population Structure of Cowpea (''Vigna unguiculata'' L. Walp)|journal=PLOS ONE|volume=11|issue=8|pages=e0160941|doi=10.1371/journal.pone.0160941|issn=1932-6203|pmc=4980000|pmid=27509049|bibcode=2016PLoSO..1160941X|doi-access=free}}</ref> Although there is no [[archaeological evidence]] for early cowpea cultivation, the [[centre of diversity]] of the cultivated cowpea is West Africa, leading an early consensus that this is the likely [[centre of origin]] and place of early domestication.<ref name="Ogunkanmi 2005">{{cite journal|last1=Ogunkanmi|first1=L. A.|last2=Taiwo|first2=A.|last3=Mogaji|first3=O. L.|last4=Awobodede|first4=A.|last5=Eziashi|first5=E. E.|last6=Ogundipe|first6=O. T.|year=2005–2006|title=Assessment of genetic diversity among cultivated cowpea (''Vigna unguiculata'' L. Walp.) cultivars from a range of localities across West Africa using agronomic traits|journal=Journal Sci. Res. Dev.|volume=10|pages=111–118}}</ref> New research using [[molecular marker]]s has suggested that domestication may have instead occurred in East Africa and currently both theories carry equal weight.<ref name=":9" />

While the date of cultivation began may be uncertain, it is still considered one of the oldest domesticated crops.<ref>{{Cite journal|last1=Chivenge|first1=Pauline|last2=Mabhaudhi|first2=Tafadzwanashe|last3=Modi|first3=Albert T.|last4=Mafongoya|first4=Paramu|date=2017|title=The Potential Role of Neglected and Underutilised Crop Species as Future Crops under Water Scarce Conditions in Sub-Saharan Africa|journal=International Journal of Environmental Research and Public Health|volume=12|issue=6|pages=5685–5711|doi=10.3390/ijerph120605685|issn=1661-7827|pmc=4483666|pmid=26016431|doi-access=free}}</ref> Remains of charred cowpeas from rock shelters in Central Ghana have been dated to the [[2nd millennium BC]].<ref>{{cite journal|last1=D'Andrea|title=Early domesticated cowpea (''Vigna unguiculata'') from Central Ghana|journal=Antiquity|date= 2007|volume=81|issue=313|pages=686–698|doi=10.1017/S0003598X00095661|s2cid=161301311 |display-authors=etal}}</ref> In 2300 BC, the cowpea is believed to have made its way into Southeast Asia, where secondary domestication events may have occurred.<ref name="Perrino 1993">{{cite journal|last1=Perrino|first1=P.|last2=Laghetti|first2=G.|last3=Spagnoletti Zeuli|first3=P. L.|last4=Monti|first4=L. M.|year=1993|title=Diversification of cowpea in the Mediterranean and other centres of cultivation.|journal=Genetic Resources and Crop Evolution|volume=40|issue=3|pages=121–132|doi=10.1007/bf00051116|bibcode=1993GRCEv..40..121P |s2cid=41138930}}</ref> From there they traveled north to the Mediterranean, where they were used by the Greeks and Romans.<ref>{{Cite book|url=https://books.google.com/books?id=XMA9gYIj-C4C&q=cowpea+cultivation+history+greek+rome&pg=PA508|title=Foods & Nutrition Encyclopedia, Two Volume Set|last1=Ensminger|first1=Marion Eugene|last2=Ensminger|first2=Audrey H.|year=1993|publisher=CRC Press|isbn=978-0-8493-8980-1|language=en}}</ref> The first written references to the cowpea were in 300 BC and they probably reached Central and North America during the [[History of slavery|slave trade]] through the 17th to early 19th centuries.<ref name="Perrino 1993" /><ref name="Ogunkanmi 2005" />

== Cultivation ==
[[File:Black-eyed pea pods on plant in Hong Kong.jpg|left|thumb|A cowpea plant with some pods ready for harvest]]
Cowpeas thrive in poor dry conditions, growing well in soils up to 85% sand.<ref>{{cite journal|last1=Obatolu|first1=V. A.|year=2003|title=Growth pattern of infants fed with a mixture of extruded malted maize and cowpea.|journal=Nutrition|volume=19|issue=2|pages=174–178|doi=10.1016/s0899-9007(02)01102-4|pmid=12591556}}</ref> This makes them a particularly important crop in arid, semidesert regions where not many other crops will grow. As well as an important source of food for humans in poor, arid regions, the crop can also be used as feed for livestock.<ref>{{cite book|last1=Quin|first1=F. M.|year=1997|chapter=Introduction|editor1-last=Singh|editor1-first=B. B.|editor2-last=Mohan Raj|editor2-first=D. R.|editor3-last= Dashiell|editor3-first=K. E.|editor4-last= Jackai|editor4-first=L. E. N.|title=Advances in Cowpea Research.|publisher=International Institute of Tropical Agriculture and Japan International Research Center for Agricultural Sciences.|location=Ibadan, Nigeria}}</ref> Its [[Nitrogen fixation|nitrogen-fixing]] ability means that as well as functioning as a sole crop, the cowpea can be effectively [[intercropped]] with [[sorghum]], [[millet]], [[maize]], [[cassava]], or [[cotton]].<ref>{{cite book|last1=Blade|first1=S. F.|last2=Shetty|first2=S. V. R.|last3=Terao|first3=T.|last4=Singh|first4=B. B.|year=1997|chapter=Recent developments in cowpea cropping systems research|editor1-last=Singh|editor1-first=B. B.|editor2-last=Mohan Raj|editor2-first=D. R.|editor3-last= Dashiell|editor3-first=K. E.|editor4-last= Jackai|editor4-first=L. E. N.|title=Advances in Cowpea Research.|publisher=International Institute of Tropical Agriculture and Japan International Research Center for Agricultural Sciences.|location=Ibadan, Nigeria}}</ref>

[[File:Wild and cultivated cowpea (7856427546).jpg|alt=|thumb|Seeds from the wild-type cowpea are much smaller than the cultivated varieties]]
The optimum temperature for cowpea growth is {{convert|30|C|F}}, making it only available as a summer crop for most of the world. It grows best in regions with an annual rainfall between {{convert|400|and|700|mm|in|abbr=on}}. The ideal soils are sandy and it has better tolerance for infertile and acid soil than most other crops. Generally, {{convert|133000|/ha|/acre|adj=pre|seeds are planted}} for the erect varieties and {{convert|60000|/ha|/acre}} for the climbing and trailing varieties. The seeds can be harvested after about 100 days or the whole plant used as forage after about 120 days. Leaves can be picked from 4 weeks after planting.<ref>{{Cite web|url=https://www.arc.agric.za/arc-gci/Fact%20Sheets%20Library/Cowpea%20-%20Production%20guidelines%20for%20cowpea.pdf|title=Production guidelines for Cowpeas|year=2011|website=South African Department of Agriculture, Forestry and Fisheries|archive-url=https://web.archive.org/web/20160803130433/https://www.arc.agric.za/arc-gci/Fact%20Sheets%20Library/Cowpea%20-%20Production%20guidelines%20for%20cowpea.pdf|archive-date=3 August 2016|url-status=live}}</ref>

These characteristics, along with its low [[Fertilisation (soil)|fertilisation]] requirements, make the cowpea an ideal crop for resource-poor farmers living in the [[Sahel]] region of West Africa. Early-maturing varieties of the crop can thrive in the [[semiarid climate]], where rainfall is often less than {{convert|500|mm|in|abbr=on}}. The timing of planting is crucial, as the plant must mature during the seasonal rains.<ref>{{Cite journal|last1=Dugje|first1=I. Y.|last2=Omoigui|first2=L. O.|last3=Ekeleme|first3=F.|last4=Kamara|first4=A. Y.|last5=Ajeigbe|first5=H.|year=2009|title=Farmers' Guide to Cowpea Production in West Africa.|journal=International Institute of Tropical Agriculture|volume=Ibadan, Nigeria}}</ref> The crop is mostly intercropped with [[pearl millet]], and plants are selected that provide both food and fodder value instead of the more specialised varieties.<ref>{{Cite journal|last1=Matsunaga|first1=R.|first2=B. B.|last2=Singh|first3=M.|last3=Adamou|first4=S.|last4=Tobita|first5=K.|last5=Hayashi|first6=A.|last6=Kamidohzono|year=2006|title=Cowpea [''Vigna unguiculata''] cultivation on the Sahelian region of west Africa: Farmers' preferences and production constraints|url=http://agris.fao.org/agris-search/search.do?recordID=JP2007003257|journal=Japanese Journal of Tropical Agriculture (Japan)|language=en|issn=0021-5260}}</ref>

Storage of the seeds can be problematic in Africa due to potential infestation by postharvest pests. Traditional methods of protecting stored grain include using the insecticidal properties of [[Neem]] extracts, mixing the grain with ash or sand, using vegetable oils, combining ash and oil into a soap solution or treating the cowpea pods with smoke or heat.<ref>{{Cite journal|last1=Poswal|first1=M. A. T.|last2=Akpa|first2=A. D.|year=1991|title=Current trends in the use of traditional and organic methods for the control of crop pests and diseases in Nigeria|journal=Tropical Pest Management|volume=37|issue=4|pages=329–333|doi=10.1080/09670879109371609|issn=0143-6147}}</ref> More modern methods include storage in airtight containers, using gamma irradiation, or heating or freezing the seeds.<ref>{{Cite journal|title=Toxicity and repellence of African plants traditionally used for the protection of stored cowpea against Callosobruchus maculatus|url=http://cat.inist.fr/?aModele=afficheN&cpsidt=15718182|journal=Journal of Stored Products Research|volume=40|issue=4|issn=0022-474X|access-date=2017-04-14|archive-url=https://web.archive.org/web/20170414163924/http://cat.inist.fr/?aModele=afficheN&cpsidt=15718182|archive-date=2017-04-14|url-status=dead}}</ref> Temperatures of {{convert|60|C|F}} kill the weevil larvae, leading to a recent push to develop cheap forms of solar heating that can be used to treat stored grain.<ref>{{Cite journal|last1=Murdock|first1=L. L.|last2=Shade|first2=R. E.|year=1991|title=Eradication of Cowpea Weevil (Coleoptera: Bruchidae)in Cowpeas by Solar Heating|journal=American Entomologist|language=en|volume=37|issue=4|pages=228–231|doi=10.1093/ae/37.4.228|issn=1046-2821|doi-access=free}}</ref> One of the more recent developments is the use a cheap, reusable double-bagging system (called [[Purdue Improved Crop Storage bags|PICs]]) that asphyxiates the cowpea weevils.<ref>{{Cite journal|last1=Baributsa|first1=D.|last2=Lowenberg-DeBoer|first2=J.|last3=Murdock|first3=L.|last4=Moussa|first4=B.|year=2010|title=Profitable chemical-free cowpea storage technology for smallholder farmers in Africa: opportunities and challenges|journal=Julius-Kühn-Archiv|language=de|issue=425|pages=1046–1052|doi=10.5073/jka.2010.425.340|issn=2199-921X}}</ref>

== Pests and diseases ==
[[File:Maruca vitrata (Crambidae Pyraustinae).jpg|thumb|Larva from the ''[[Maruca vitrata]]'', commonly called the maruca pod borer, is one of the most damaging insect pests to the cowpea plant.]]
Insects are a major factor in the low yields of African cowpea crops, and they affect each tissue component and developmental stage of the plant. In bad infestations, insect pressure is responsible for over 90% loss in yield.<ref name=":3">{{cite journal |last1=Jackai |first1=L. E. N. |last2=Daoust |first2=R. A. |year=1986 |title=Insect pests of cowpeas |journal=Annual Review of Entomology|volume=31 |pages=95–119 |doi=10.1146/annurev.ento.31.1.95}}</ref> The legume pod borer, ''[[Maruca vitrata]],'' is the main preharvest pest of the cowpea.<ref>{{cite journal|last=Sharma |first=H. C. |year=1998|title= Bionomics, host plant resistance, and management of the legume pod borer, ''Maruca vitrata'' |journal=Crop Protection |volume=7 |issue=5 |pages=373–386 |doi=10.1016/s0261-2194(98)00045-3|bibcode=1998CrPro..17..373S |url=http://oar.icrisat.org/1700/1/CropProt17%285%29373-386_1998.pdf }}</ref> Other important pests include [[Hemiptera|pod sucking bugs]], [[thrips]], [[aphid]]s, [[Chalcodermus aeneus|cowpea curculios]] and post-harvest beetles ''[[Callosobruchus maculatus]]'' and ''[[Callosobruchus chinensis]]''.<ref name=":3" /><ref name="insects">{{cite web| last=Heath |first=Jeffrey |author-link=Jeffrey Heath |title=Guide to insects, arthropods, and molluscs of northern Dogon country |url=https://dogonlanguages.org/sources/insectarthropodmolluscnotesmalijh}}</ref><ref name="Jackai-Daoust-1986">{{cite journal | last1=Jackai | first1=L E N | last2=Daoust | first2=R A | title=Insect Pests of Cowpeas | journal=[[Annual Review of Entomology]] | publisher=[[Annual Reviews (publisher)|Annual Reviews]] | volume=31 | issue=1 | year=1986 | issn=0066-4170 | doi=10.1146/annurev.en.31.010186.000523 | pages=95–119}}</ref><ref>{{cite web |last1=Capinera |first1=John |title=EENY223/IN380: Cowpea Curculio, Chalcodermus aeneus Boheman (Insecta: Coleoptera: Curculionidae) |url=https://edis.ifas.ufl.edu/publication/IN380 |website=University of Florida, Institute of Food and Agricultural Sciences |access-date=15 June 2023}}</ref><ref>{{Cite web |date=2006-11-26 |title=Callosobruchus chinensis, The Pulse Beetle {{!}} Zoology for IAS, IFoS and other competitive exams |url=https://www.iaszoology.com/callosobruchus-chinensis/ |access-date=2024-04-23 |language=en-GB}}</ref>

''M. vitrata'' causes the most damage to the growing cowpea due to their large [[Host (biology)|host range]] and [[cosmopolitan distribution]].<ref name=":10">{{Cite journal|last1=Jayasinghe |first1=R. C. |last2=Premachandra|first2=W. T. S. Dammini |last3=Neilson|first3=Roy |year=2015|title=A study on ''Maruca vitrata'' infestation of Yard-long beans (''Vigna unguiculata'' subspecies ''sesquipedalis'') |journal=Heliyon|volume=1|issue=1 |doi=10.1016/j.heliyon.2015.e00014 |pmc=4939760 |pmid=27441212 |page=e00014|doi-access=free |bibcode=2015Heliy...100014J }}</ref> It causes damage to the flower buds, flowers, and pods of the plant, with infestations resulting in a 20–88% loss of yield.<ref name=":10" /> While the insect can cause damage through all growth stages, most of the damage occurs during flowering.<ref name=":10" /> [[Biological pest control|Biological control]] has had limited success, so most preventive methods rely on the use of [[Agrochemical|agrichemicals]]. [[Genetically modified crops|Genetically modified]] cowpeas has been developed to express the [[Cry toxin|cry protein]] from ''[[Bacillus thuringiensis]]'', which is toxic to [[lepidoptera]]n species including the maruca.<ref>{{Cite journal|last1=Agunbiade |first1=Tolulope A.|last2=Coates|first2=Brad S.|last3=Datinon |first3=Benjamin |last4=Djouaka |first4=Rousseau|last5=Sun |first5=Weilin |last6=Tamò |first6=Manuele |last7=Pittendrigh |first7=Barry R.|year=2014 |title=Genetic Differentiation among Maruca vitrata F. (Lepidoptera: Crambidae) Populations on Cultivated Cowpea and Wild Host Plants: Implications for Insect Resistance Management and Biological Control Strategies|journal=PLOS ONE |volume=9 |issue=3 |doi=10.1371/journal.pone.0092072 |pmc=3960178 |pmid=24647356 |page=e92072|bibcode=2014PLoSO...992072A|doi-access=free}}</ref> BT Cowpea was commercialised in Nigeria in 2019.<ref>{{cite web |last1=Opoku Gakpo |first1=Joseph |title=Nigerian GMO cowpea farmers testify to reduced pest infestation and better yields |url=https://allianceforscience.cornell.edu/blog/2021/11/nigerian-gmo-cowpea-farmers-testify-to-reduced-pest-infestation-and-better-yields/ |website=Allianceforscience |access-date=26 January 2022}}</ref>

[[File:CSIRO ScienceImage 489 Cowpea bean varieties infested with weevils.jpg|left|thumb|Cowpea weevil (''[[Callosobruchus maculatus]]'') infests stored cowpea seeds, resulting in major postharvest losses.]]
Severe ''C. maculatus'' infestations can affect 100% of the stored peas and cause up to 60% loss within a few months.<ref>{{Cite journal |last1=Kang |first1=Jung Koo |last2=Pittendrigh |first2=Barry R. |last3=Onstad |first3=David W. |year=2013 |title=Insect resistance management for stored product pests: a case study of cowpea weevil (Coleoptera: Bruchidae)|journal=Journal of Economic Entomology |volume=106 |issue=6 |pages=2473–2490 |pmid=24498750 |doi=10.1603/ec13340|s2cid=21508673 }}</ref><ref>{{Cite journal |last1=Tarver |first1=Matthew R.|last2=Shade |first2=Richard E. |last3=Shukle|first3=Richard H. |last4=Moar |first4=William J.|last5=Muir |first5=William M.|last6=Murdock |first6=Larry M. |last7=Pittendrigh |first7=Barry R. |year=2007 |title=Pyramiding of insecticidal compounds for control of the cowpea bruchid (Callosobruchus maculatus F.) |journal=Pest Management Science|language=en|volume=63 |issue=5|pages=440–446 |doi=10.1002/ps.1343|pmid=17340671}}</ref> The [[Bean weevil|weevil]] generally enters the cowpea pod through holes before harvest and lays eggs on the dry seed.<ref>{{Cite journal |last1=Mashela |first1=P. |last2=Pofu |first2=K. |year=2012 |title=Storing cowpea (''Vigna unguiculata'') seeds in active cattle kraals for suppression of Callosobruchus maculatus |journal=African Journal of Biotechnology |volume=11 |pages=14713–14715}}</ref> The larvae burrow their way into the seed, feeding on the [[endosperm]]. The weevil develops into a sexually mature adult within the seed.<ref>{{Cite journal |last=Wilson|first=Kenneth|year=1988|title=Egg laying decisions by the bean weevil Callosobruchus maculatus |journal=Ecological Entomology |language=en |volume=13|issue=1 |pages=107–118 |doi=10.1111/j.1365-2311.1988.tb00338.x|bibcode=1988EcoEn..13..107W |s2cid=85942098}}</ref> An individual bruchid can lay 20–40 eggs, and in optimal conditions, each egg can develop into a reproductively active adult in 3 weeks.<ref>{{Cite journal |last1=Murdock |first1=Larry L. |last2=Seck |first2=Dogo |last3=Ntoukam |first3=Georges |last4=Kitch |first4=Laurie |last5=Shade |first5=R. E. |year=2003 |title=Preservation of cowpea grain in sub-Saharan Africa—Bean/Cowpea CRSP contributions |journal=Field Crops Research |series=Research Highlights of the Bean/Cowpea Collaborative Research Support Program, 1981–2002 |volume=82 |issue=2–3 |pages=169–178 |doi=10.1016/S0378-4290(03)00036-4|bibcode=2003FCrRe..82..169M }}</ref> The most common methods of protection involve the use of insecticides, the main pesticides used being [[carbamate]]s, synthetic [[pyrethroid]]s, and [[organophosphate]]s.<ref>{{Cite book|chapter-url=https://books.google.com/books?id=s_5Y5BFRU1EC&q=Pest+management+practices+in+cowpea%3A+a+review&pg=PA240|title=Advances in Cowpea Research|chapter=Pest management practices in cowpea: a review |editor1-last=Singh |editor1-first=B. B. |last1=Jackai |first1=L. E. N. |last2=Adalla |first2=C. B. |year=1997 |publisher=IITA |pages=240–258 |isbn=978-978-131-110-9 |language=en}}</ref>

Cowpea is susceptible to [[nematode]], fungal, bacterial, and virus diseases, which can result in substantial loss in yield.<ref>{{Cite journal  |title=The control of weed, pest and disease complexes in cowpea (''Vigna unguiculata'' (L.) Walp.) by the application of pesticides singly and in combination|doi=10.1016/0261-2194(87)90042-1 |language=en |volume=6 |issue=4|journal=Crop Protection |pages=222–225|year=1987|last1=Olowe|first1=T.|last2=Dina|first2=S.O.|last3=Oladiran|first3=A.O.|last4=Olunuga|first4=B.A.|bibcode=1987CrPro...6..222O }}</ref> Common diseases include [[blight]]s, root rot, wilt, [[powdery mildew]], root knot, [[Rust (fungus)|rust]] and [[leaf spot]].<ref name=":11">{{Cite web |url=http://plantdiseasehandbook.tamu.edu/food-crops/vegetable-crops/southern-pea-blackeye-cowpea/ |title=Southern Pea (Blackeye, Cowpea)|publisher=Texas Plant Disease Handbook |website=plantdiseasehandbook.tamu.edu |access-date=2017-04-14}}</ref> The plant is susceptible to [[mosaic virus]]es, which cause a green mosaic pattern to appear in the leaves.<ref name=":11" /> The [[cowpea mosaic virus]] (CPMV), discovered in 1959, has become a useful research tool.<ref name=":12">{{Cite journal |title=Cowpea mosaic Virus: The Plant Virus–Based Biotechnology Workhorse |journal = Annual Review of Phytopathology|volume = 48|pages = 437–455|last1=Sainsbury |first1=Frank |last2=Cañizares |first2=M. Carmen |year=2010 |doi=10.1146/annurev-phyto-073009-114242 |pmid = 20455698|last3=Lomonossoff |first3=George P.| issue=1 | bibcode=2010AnRvP..48..437S |hdl = 10261/29182|hdl-access=free }}</ref> CPMV is stable and easy to propagate to a high yield, making it useful in [[Vector (molecular biology)|vector]] development and [[Protein expression (biotechnology)|protein expression systems]].<ref name=":12" /> One of the plant's defenses against some insect attacks is the cowpea [[trypsin inhibitor]] (CpTI).<ref>{{Cite journal |last1=Boulter |first1=D. |last2=Gatehouse |first2=A. M. R.|author-link2=Angharad Gatehouse |last3=Hilder|first3=V.|title=Use of cowpea trypsin inhibitor (CpTI) to protect plants against insect predation|journal=Biotechnology Advances |volume=7 |issue=4 |pages=489–497 |doi=10.1016/0734-9750(89)90720-9|pmid=14542987 |year=1989 }}</ref> CpTI has been [[transgenics|transgenically]] inserted into other crops as a [[insect repellent|pest deterrent]].<ref name="Gatehouse-et-al-1997" /> ''CpTI'' is the only gene obtained outside of ''B. thuringiensis'' that has been inserted into a commercially available genetically modified crop.<ref>{{Cite journal |last1=Wu |first1=Hongsheng |last2=Zhang |first2=Yuhong |last3=Liu |first3=Ping |last4=Xie |first4=Jiaqin |last5=He |first5=Yunyu |last6=Deng |first6=Congshuang |last7=Clercq |first7=Patrick De |last8=Pang |first8=Hong |year=2014 |title=Effects of Transgenic Cry1Ac + CpTI Cotton on Non-Target Mealybug Pest ''Ferrisia virgata'' and its Predator ''Cryptolaemus montrouzieri'' |journal=PLOS ONE |volume=9 |issue=4 |pages=95537 |doi=10.1371/journal.pone.0095537 |pmc=3994093 |pmid=24751821|bibcode=2014PLoSO...995537W |doi-access=free }}</ref>

Besides biotic stresses, cowpea also faces various challenges in different parts of the world such as drought, heat, and cold.<ref>{{Cite journal|last1=Ajayi|first1=Abiola|last2=Gbadamosi|first2=Alaba|last3=Olumekun|first3=Victor|date=2018-01-01|title=Screening for Drought Tolerance in Cowpea (Vigna unguiculata L. Walp) at Seedling Stage under Screen House Condition|url=https://www.researchgate.net/publication/322203394}}</ref> Drought lowers the growth rate and development, ultimately reducing yield, although cowpea is considered more drought tolerant than most other crops.<ref>{{Cite journal|last1=Olajide|first1=Amos Afolarin|last2=Ilori|first2=Christopher Olumuyiwa|date=2017|title=Effects of Drought on Morphological Traits in Some Cowpea Genotypes by Evaluating Their Combining Abilities|journal=Advances in Agriculture|language=en|volume=2017|issue=1 |pages=1–10|doi=10.1155/2017/7265726|issn=2356-654X|doi-access=free|bibcode=2017AdvAg201765726O }}</ref> Drought at the preflowering stage in cowpea can reduce the yield potential by 360&nbsp;kg/ha.<ref>{{Cite journal|date=2016-03-01|title=Drought tolerance in cowpea species is driven by less sensitivity of leaf gas exchange to water deficit and rapid recovery of photosynthesis after rehydration|journal=South African Journal of Botany|language=en|volume=103|pages=101–107|doi=10.1016/j.sajb.2015.08.008|issn=0254-6299|last1=Rivas|first1=R.|last2=Falcão|first2=H.M.|last3=Ribeiro|first3=R.V.|last4=Machado|first4=E.C.|last5=Pimentel|first5=C.|last6=Santos|first6=M.G.|doi-access=free|bibcode=2016SAJB..103..101R }}</ref> Crop wild relatives are the prominent source of genetic material, which can be tapped to improve biotic/abiotic tolerance in crops.<ref>{{Cite journal|last1=Iseki|first1=Kohtaro|last2=Takahashi|first2=Yu|last3=Muto|first3=Chiaki|last4=Naito|first4=Ken|last5=Tomooka|first5=Norihiko|date=2018-06-15|title=Diversity of Drought Tolerance in the Genus Vigna|journal=Frontiers in Plant Science|volume=9|pages=729|doi=10.3389/fpls.2018.00729|issn=1664-462X|pmc=6014140|pmid=29963062|doi-access=free|bibcode=2018FrPS....9..729I }}</ref> [[International Institute of Tropical Agriculture]] (IITA), Nigeria and Institut de l'Environment et de Recherches Agricoles are looking to tap into the genetic diversity of wild cowpeas and transfer that into cultivars to make them more tolerant to different stresses and adaptive to climate change.<ref>{{Cite web|url=https://www.cwrdiversity.org/partnership/cowpea-pre-breeding-project/|title=CWR » Cowpea Pre-breeding Project|website=www.cwrdiversity.org|language=en-US|access-date=2018-08-15}}</ref>

== Culinary use ==
{{Cookbook|Cowpea}}[[File:Hoppin-john-bowl.JPG|thumb|[[Hoppin' John]] is a common meal in the rural Southern United States.|alt=|left]]
Cowpeas are grown mostly for their edible beans, although the leaves, green seeds and pods can also be consumed, meaning the cowpea can be used as a food source before the dried peas are harvested.<ref>{{cite journal|last1=Ehlers|first1=J. D.|last2=Hall|first2=A. E.|year=1997|title=Cowpea (''Vigna unguiculata'' L. Walp.)|journal=Field Crops Res|volume=53|issue=1–3|pages=187–204|doi=10.1016/s0378-4290(97)00031-2|bibcode=1997FCrRe..53..187E }}</ref> Like other [[legume]]s, cowpeas are cooked to make them edible, usually by boiling.<ref name=":13">{{Cite journal|last1=Hamid|first1=Saima|last2=Muzaffar|first2=Sabeera|last3=Wani|first3=Idrees Ahmed|last4=Masoodi|first4=Farooq Ahmad|last5=Bhat|first5=Mohd. Munaf|year=2016|title=Physical and cooking characteristics of two cowpea cultivars grown in temperate Indian climate|journal=Journal of the Saudi Society of Agricultural Sciences|volume=15|issue=2|pages=127–134|doi=10.1016/j.jssas.2014.08.002|doi-access=free}}</ref> Cowpeas can be prepared in stews, soups, purees, casseroles and curries.<ref name=":14">{{Cite news|url=http://www.africanfoods.co.uk/cowpeas-recipe.html|title=Cowpeas Recipe|work=African Foods|access-date=2017-04-14}}</ref><ref>{{Cite web|url=http://africaimports.com/poultry6.asp?url=|title=Africa Imports - African Recipes - Red-Red Stew|website=africaimports.com|access-date=2017-04-14}}</ref> They can also be processed into a paste or flour.<ref name=":15">{{Cite journal|last1=Gonçalves|first1=Alexandre|last2=Goufo|first2=Piebiep|last3=Barros|first3=Ana|last4=Domínguez-Perles|first4=Raúl|last5=Trindade|first5=Henrique|last6=Rosa|first6=Eduardo A. S.|last7=Ferreira|first7=Luis|last8=Rodrigues|first8=Miguel|year=2016|title=Cowpea (''Vigna unguiculata'' L. Walp), a renewed multipurpose crop for a more sustainable agrifood system: nutritional advantages and constraints|journal=Journal of the Science of Food and Agriculture|language=en|volume=96|issue=9|pages=2941–2951|doi=10.1002/jsfa.7644|pmid=26804459|bibcode=2016JSFA...96.2941G |issn=1097-0010}}</ref> Chinese long beans can be eaten raw or cooked, but as they easily become waterlogged are usually sautéed, stir-fried, or deep-fried.<ref>{{Cite news|url=https://food52.com/blog/14265-the-long-and-the-short-of-yard-long-beans|title=The Long and the Short of Yard-Long Beans|year=2015|work=Food52|access-date=2017-04-14|language=en}}</ref>

A common snack in Africa is ''koki'' or ''moin-moin'', where the cowpeas are mashed into a paste, mixed with spices and steamed in banana leaves.<ref>{{Cite web|url=http://www.congocookbook.com/snack_recipes/koki.html|title=Koki|website=The Congo Cookbook|language=en|access-date=2017-04-14|archive-url=https://web.archive.org/web/20170518010156/http://www.congocookbook.com/snack_recipes/koki.html|archive-date=2017-05-18|url-status=dead}}</ref> [[Dan wake]] cowpea dumplings are common in northern Nigeria and environs.<ref>{{cite journal |last1=Sani |first1=M. H. |first2=U. F. |last2=Abubakar |first3=R. M. |last3=Sani |title=Households' Preference and Usage of Cowpea-Based Products and Varieties in Western Zone of Bauchi State, Nigeria |journal=Journal of Agripreneurship and Sustainable Development |volume=5 |issue=1 |year=2022 |pages=16–29|doi=10.59331/jasd.v5i1.284 |doi-access=free }}</ref> They also use the cowpea paste as a supplement in [[infant formula]] when weaning babies off milk.<ref>{{Cite journal|last1=Oyeleke |first1=O. A.|last2=Morton|first2=I. D.|last3=Bender|first3=A. E.|year=1985|title=The use of cowpeas (''Vigna unguiculata'') in improving a popular Nigerian weaning food|journal=The British Journal of Nutrition|volume=54|issue=2|pages=343–347|issn=0007-1145|pmid=4063322|doi=10.1079/bjn19850119|s2cid=17382544|doi-access=free}}</ref> Slaves brought to America and the West Indies cooked cowpeas much the same way as they did in Africa, although many people in the [[American south|American South]] considered cowpeas not suitable for human consumption.<ref>{{Cite book|url=https://books.google.com/books?id=xhpBsIa5yqEC&q=cowpeas+cookbook&pg=PA84 |title=What the Slaves Ate: Recollections of African American Foods and Foodways from the Slave Narratives |last1=Covey |first1=Herbert C.|last2=Eisnach |first2=Dwight|year=2009 |publisher=ABC-CLIO |isbn=978-0-313-37497-5 |language=en}}</ref> A popular dish was [[Hoppin' John]], which contained black-eyed peas cooked with rice and seasoned with pork. Over time, cowpeas became more universally accepted and now Hoppin' John is seen as a traditional Southern dish ritually served on New Year's Day.<ref>{{Cite news|url=https://www.nytimes.com/2015/12/30/dining/black-eyed-peas-cowpea-field-peas.html|title=Field Peas, a Southern Good Luck Charm|last=Severson|first=Kim|year=2015|work=The New York Times|access-date=2017-04-14|issn=0362-4331}}</ref>

== Nutrition and health ==
{{nutritional value | name= Cowpea (raw seeds)
| water=11.95&nbsp;g 
| kcal=336
| protein=23.52&nbsp;g 
| fat=1.26&nbsp;g 
| carbs=60.03&nbsp;g 
| fiber=10.6&nbsp;g
| sugars=6.9&nbsp;g
| calcium_mg=110
| iron_mg=8.27
| magnesium_mg=184
| phosphorus_mg=424
| potassium_mg=1112
| sodium_mg=16
| zinc_mg=3.37
| vitC_mg=1.5
| thiamin_mg=0.853
| riboflavin_mg=0.226
| niacin_mg=2.075
| vitB6_mg=0.357
| folate_ug=633
| vitA_ug=3 
| vitA_IU=50
| vitK_ug=5
| satfat_g= 0.331
| transfat_g=
| monofat_g= 0.011
| polyfat_g=0.542
| source_usda=1
| note=[https://web.archive.org/web/20190910192920/https://ndb.nal.usda.gov/ndb/foods/show/4801?manu=&fgcd=&ds= Link to USDA Database entry]
}}
Cowpea seeds provide a rich source of proteins and [[food energy]], as well as minerals and vitamins.<ref name=":15" /> This complements the mainly [[cereal]] diet in countries that grow cowpeas as a major food crop.<ref>{{cite journal |last1=Phillips|first1=R. D.|last2=McWatters|first2=K. H.|last3=Chinnan|first3=M. S.|last4=Hung|first4=Y. C. |last5=Beuchat|first5=L. R.|last6=Sefa-Dedeh|first6=S.|last7=Sakyi-Dawson |first7=E.|last8=Ngoddy |first8=P.|last9=Nnanyelugo |first9=D.|last10=Enwere|first10=J.|year=2003 |title=Utilization of cowpeas for human food.|journal=Field Crops Res.|volume=82 |issue=2–3|pages=193–213 |doi=10.1016/s0378-4290(03)00038-8|bibcode=2003FCrRe..82..193P }}</ref> A seed can consist of 25% protein and has very low fat content.<ref>{{cite journal |last1=Rangel|first1=A.|last2=Domont|first2=G. B. |last3=Pedrosa |first3=C.|last4=Ferreira|first4=S. T. |year=2003|title=Functional properties of purified vicilins from cowpea (''Vigna unguiculata'') and pea (''Pisum sativum'') and cowpea protein isolate |journal=Journal of Agricultural and Food Chemistry |volume=51 |issue=19|pages=5792–5797 |doi=10.1021/jf0340052|pmid=12952435|bibcode=2003JAFC...51.5792R }}</ref> Cowpea [[starch]] is digested more slowly than the starch from cereals, which is more beneficial to human health.<ref name=":15" /> The grain is a rich source of [[folic acid]], an important vitamin that helps prevent [[neural tube defect]]s in unborn babies.<ref>{{Cite book |doi=10.1016/B978-0-12-384947-2.00300-7|title=Encyclopedia of Food and Health |last1=Witthöft |first1=C. |last2=Hefni |first2=M. |year=2016 |publisher=Academic Press |isbn=978-0-12-384953-3 |location=Oxford |pages=724–730}}</ref>

The cowpea has often been referred to as "poor man's meat" due to the high levels of protein found in the seeds and leaves.<ref name=":13" /> However, it does contain some [[Antinutrient|antinutritional]] elements, notable [[phytic acid]] and [[Protease inhibitor (biology)|protease inhibitors]], which reduce the nutritional value of the crop.<ref name=":15" /> Methods such as fermentation, soaking, germination, debranning, and autoclaving are used to combat the antinutritional properties of the cowpea by increasing the bioavailability of nutrients within the crop.<ref>{{Cite journal|last1=Owade|first1=Joshua O.|last2=Abong’|first2=George|last3=Okoth|first3=Michael|last4=Mwang’ombe|first4=Agnes W.|date=2019-12-17|title=A review of the contribution of cowpea leaves to food and nutrition security in East Africa|journal=Food Science & Nutrition|volume=8|issue=1|pages=36–47|doi=10.1002/fsn3.1337|issn=2048-7177|pmc=6977510|pmid=31993130}}</ref> Although little research has been conducted on the nutritional value of the leaves and immature pods, what is available suggests that the leaves have a similar nutritional value to [[Solanum nigrum|black nightshade]] and [[sweet potato]] leaves, while the green pods have less antinutritional factors than the dried seeds.<ref name=":15" />

== Production and consumption ==
{| class="wikitable plainrowheaders" style="text-align:right; float:right; margin-top:0; margin-left:2em;"
|+ Cow peas, dry production, 2020<ref name="fao">{{cite web|url=https://www.fao.org/faostat/en/#data/QCL|title= Cow peas, dry production in 2020, Crops/Regions/World list/Production Quantity (pick lists)|date=2022|publisher=UN Food and Agriculture Organization, Corporate Statistical Database (FAOSTAT)|access-date=10 September 2022}}</ref>
|-
!scope="col"| Country
!scope="col"| Weight ([[tonne]]s)
|-
!scope="row"| {{NGA}}
| 3,647,115
|-
!scope="row"| {{NER}}
| 2,637,486
|-
!scope="row"| {{BFA}}
| 666,023
|-
!scope="row"| {{KEN}}
| 264,160
|-
!scope="row"| {{SEN}}
| 253,897
|-
!scope="row"| All others
| 1,447,422
|-
!scope="row"|'''World'''
|'''8,916,103'''
|}
Most cowpeas are grown on the African continent, particularly in Nigeria and Niger, which account for 66% of world cowpea production.<ref name=":4">[http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567#ancor 24/01/2015 FAO 2012 FAOSTAT Gateway] {{webarchive |url=https://web.archive.org/web/20150906230329/http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567#ancor |date=September 6, 2015 }}</ref> The Sahel region also contains other major producers such as [[Burkina Faso]], [[Ghana]], [[Senegal]], and [[Mali]]. Niger is the main exporter of cowpeas and Nigeria the main importer. Exact figures for cowpea production are hard to come up with as it is not a major export crop. Estimating world cowpea production is rather difficult, as it is usually grown in a mixture with other crops, but according to a 1997 estimate, cowpeas were cultivated on {{convert|12.5|ha||disp=preunit|million }} and had a worldwide production of {{convert|3|e6MT}}.<ref name="Singh 1997" >{{cite book|chapter-url=http://pdf.usaid.gov/pdf_docs/pnacb024.pdf|title=Advances in Cowpea Research |first1=B. B.|last1=Singh|first2=O. L.|last2=Chambliss|last3=Sharma|first3=B.|editor2-last=Mohan|editor2-first=D. R.|editor3-last=Dashiell|editor3-first=K. E.|editor4-last=Jackai|editor4-first=L. E. N.|publisher=[[International Institute of Tropical Agriculture]] and Japan International Research Center for Agricultural Sciences|year=1997|location=Ibadan, Nigeria|chapter=Recent advances in cowpea breeding |editor1-last=Singh|editor1-first=B. B.}}</ref> While they play a key role in subsistence farming and livestock fodder, the cowpea is also seen as a major cash crop by Central and West African farmers, with an estimated 200 million people consuming cowpea on a daily basis.<ref name="Langyintuo 2003">{{cite journal|last1=Langyintuo|first1=A. S.|last2=Lowenberg-Deboer |first2=J. |last3=Faye |first3=M. |last4=Lambert |first4=D.|last5=Ibro|first5=G. |last6=Moussa|first6=B. |last7=Kergna |first7= A.|last8=Kushwaha |first8=S.|last9=Musa |first9=S.|last10=Ntoukam |first10=G. |year=2003 |title=Cowpea supply and demand in West and Central Africa |journal=Field Crops Research |volume=82 |issue=2–3|pages=215–231 |doi=10.1016/s0378-4290(03)00039-x|bibcode=2003FCrRe..82..215L }}</ref>

According to the [[Food and Agriculture Organization of the United Nations]], as of 2012, the average cowpea yield in Western Africa was an estimated {{convert|483|kg/ha|lb/acre}},<ref name=":4" /> which is still 50% below the estimated potential production yield.<ref>{{cite book |last1=Kormawa|first1=P. M.|last2=Chianu|first2=J. N.|last3=Manyong |first3=V. M. |year=2002 |chapter=Cowpea demand and supply patterns in West Africa: the case of Nigeria |editor1-last=Fatokun |editor1-first=C. A. |editor2-last=Tarawali |editor2-first=S. A.|editor3-last=Singh |editor3-first=B. B.|editor4-last=Kormawa|editor4-first=P. M.|editor5-last=Tamo |editor5-first=M. |title=Challenges and Opportunities for enhancing sustainable Cowpea production |publisher=International Institute of Tropical Agriculture}}</ref> In some tradition cropping methods, the yield can be as low as {{convert|100|kg/ha|lb/acre}}.<ref name=":17" />

Outside Africa, the major production areas are Asia, [[Central America]], and [[South America]]. [[Brazil]] is the world's second-leading producer of cowpea seed, accounting for 17% of annual cowpea production, although most is consumed within the country.<ref name="postharvest">{{Cite web |url=http://www.fao.org/fileadmin/templates/inpho/documents/Cowpea%20Postharvest%20III%20Definit.pdf|title=Cowpea Post-harvest Operations|last=Gómez |first=Carlos |date=2004 |website=Food and Agriculture Organization of the United Nations|language=en |access-date=2017-04-19}}</ref>

== References ==
{{Reflist|30em|refs=

<ref name="Gatehouse-et-al-1997">{{cite journal | title=Transgenic potato plants with enhanced resistance to the tomato moth, ''Lacanobia oleracea'': growth room trials | s2cid=23765916 | last1=Gatehouse | first1=Angharad M.R. | last2=Davison | first2=Gillian M. | last3=Newell | first3=Christine A. | last4=Merryweather | first4=Andrew | last5=Hamilton | first5=William D.O. | last6=Burgess | first6=Elisabeth P.J. | last7=Gilbert | first7=Robert J.C. | last8=Gatehouse | first8=John A. | journal=[[Molecular Breeding (journal)|Molecular Breeding]] | publisher=[[Springer Science+Business Media|Springer Science+Business]] | volume=3 | issue=1 | year=1997 | issn=1380-3743 | doi=10.1023/a:1009600321838 | pages=49–63| bibcode=1997MBree...3...49G }}</ref>

}}

== External links ==
{{Commons category|Vigna unguiculata|Cowpea}}
*[https://www.iita.org/cowpea/ Cowpea research at the International Institute of Tropical Agriculture (IITA)]
* [http://www.entm.purdue.edu/NGICA/ Network for Genetic Improvement of Cowpea for All (NGICA)]
* [http://www.oecd.org/officialdocuments/publicdisplaydocumentpdf/?cote=env%2Fjm%2Fmono(2018)36&doclanguage=en Consensus Document on Compositional Considerations for New Varieties of COWPEA (Vigna unguiculata): Key Food and Feed Nutrients, Anti-nutrients and Other Constituents, OECD Series on the Safety of Novel Foods and Feeds No. 30]
* Adam D. Steinbrenner, Maria Muñoz-Amatriaín, Antonio F. Chaparro, Jessica Montserrat Aguilar-Venegas, Sassoum Lo, Satohiro Okuda, Gaetan Glauser, Julien Dongiovanni, Da Shi, Marlo Hall, Daniel Crubaugh, Nicholas Holton, Cyril Zipfel, Ruben Abagyan, Ted C. J. Turlings, Timothy J. Close, Alisa Huffaker, and Eric A. Schmelz: [https://www.pnas.org/content/early/2020/11/20/2018415117 A receptor-like protein mediates plant immune responses to herbivore-associated molecular patterns]. In: PNAS. November 23, 2020. [[doi:10.1073/pnas.2018415117]]. See also:
:* Carly Cassella: [https://www.sciencealert.com/black-eyed-peas-can-sense-the-saliva-of-very-hungry-caterpillars-and-fight-back Saliva From Hungry Caterpillars Alerts Cowpea Plants to Turn on Their Defenses]. On: science<sup>alert</sup>. 5 December 2020
{{WestAfricanPlants|Vigna unguiculata}}

{{Taxonbar|from=Q498940}}
{{Authority control}}

[[Category:Edible legumes]]
[[Category:Flora of Nepal]]
[[Category:Nitrogen-fixing crops]]
[[Category:Vigna]]
[[Category:Taxa named by Wilhelm Gerhard Walpers]]