COWPEA(beans) &-8211; this Article or News was published on this date:2019-05-16 07:09:32 kindly share it with friends if you find it helpful

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Cowpea is the most economically important indigenous African legume and most versatile African crop which feeds people, their livestock, the soil and other crops. In Nigeria it is simply known as ‘beans’. If you ask a layman in Nigeria what cowpea is, you would have a hard time finding the right answer but once you say Beans, they know exactly what you mean. There are two major varieties that are popularly known to people in southwest Nigeria; sweet beans or honey beans (ewa oloyin) and Nigerian brown beans (ewa drum).

Botanically, it is called Vigna unguiculata and is grown in the semi-arid tropics which cover Asia, Far East, Africa, Central and South America. Cowpea has its root in Africa most especially South, West and East Africa but the name Cowpea probably emerged when it got to the United States of America and was used as an important feed for Cow.

There are a lot of great reasons why one should cultivate this crop; it can tolerate low rainfall and shortage of water, performs well in a wide variety of soils, and being a legume, it replenishes low fertility soils when the roots are left to decay, which makes it an ideal crop for crop rotation.

Cowpea is an annual herb which has a growth form that varies; it can be bushy, trailing, erect or climbing. Its root is a taproot which is quite strong and with many spreading lateral roots in surface soil. The stems of cowpea are striate, smooth or slightly hairy. Its leaves are in alternate pattern and are trifoliate, the colour of the leaves is dark green and shape varies from linear-lanceolate to ovate. Cowpea seeds also vary in size, shape and colour and the number of seeds per pod also varies.



Cowpea is an important economic crop, because of its various attributes such as: ability to adapt to different type of soils and suitability for intercropping, it grows and covers the topmost soil which in turn prevents erosion, all parts of Cowpea are useful even the leaves which can produce 9 times the calories, 15 times the protein, 90 times the calcium and thousands of times more vitamin C and beta-carotene of cowpea seed. Cowpea also complements a lot of cereal crops.



Climatic condition requirements for cowpea&-8211; During growing season the temperature range for cowpea is between 280C-300C, its rainfall range is between 500-1200mm/year but some variety can thrive in areas with less than 500mm, in a nutshell this means cowpea will still survive in areas with low rainfall, although Cowpea requires enough moisture during the germinating period.


Soil Requirements

Cowpea does well on any soil but the best soil for cowpea is well-drained Sandy loam soil or Sandy soil with a soil pH in the range of 6 to 7, although its sensitive to water-logging conditions.



Cowpea is propagated by seeds.


Pre-Planting Operations

Land Preparation

The farm land should be cleared, removing shrubs and especially stubble; it can be sprayed with herbicide to stop the emergence of weed on the land, it should be plowed or harrowed for good root growth, you can also make ridges if you want. In a situation where the soil is fragile and prone to erosion one can make use of Zero tillage (this a process whereby one uses herbicides to control weeds and maintains crop residue on the soil surface)

Seedbed Preparation

The soil should be well tilled or pulverized (act of grinding to powder or dust) to ensure that the root of the Cowpea which is a taproot does not encounter any obstacle such as hardpan (a hardened layer, which happens in the soil and impairs drainage and affects plant growth), for easy penetration into the soil. The topsoil can either be ridged or left flat as seedbeds.


Cowpea does not necessarily need nitrogen fertilizer, but in cases whereby the land has been used continuously for farming purposes, application of starter dose of Nitrogen up to 20kg/ha is good, especially when the organic matter is as low as 1%. For soils in Sudan and Sahel region in Africa, they are very low in phosphorous and potash and therefore phosphorous should be added as a single superphosphate, it does not only increase yield but also nodulation in Cowpea.



The inter-row and intra-row spacing depends on the type of variety of cowpea grown and the growing pattern, but generally for grain production, a plant population of 200,000 to 300,000/ha at 30 to 50cm inter-row spacing is preferred.

The seed should be planted at 3cm to 4cm deep. Planting should be timed in relation to the maturity period, such that the crop is harvested in bright dry weather.  It’s best to sow when the soil is moist or wet, i.e. when the rainfall is reduced. The date of planting should be timed in such a way that will allow the crop to escape from periods of high pest, and harvesting to coincide with the period of dry weather because harvesting under humid cloudy weather favours pod rot.

If the farmer is to plant cowpea twice in a year it is advised for the first crop be planted in April and the second in late July to mid-August, if planting the same variety the older seeds should be planted not the recently harvested seeds, because seeds that are not properly dried fail to germinate well and plant stands are reduced. Also, seeds that will be planted must be sorted to make sure that they are free from insect damage that is it has no holes or wrinkles and are disease free.

Weed Control

Weeds are unwanted plants which causes harm to a plant by competing for nutrients, lights, water and sunlight. Cowpea cannot easily withstand the competition of weed, especially at the early growing stage, if the weed is not well managed or controlled, it can accommodate pest and also reduce the yield and quality of the Cowpea. The type of control measure carried out, should be based on the nature of the weed. The weeding should be done 2 weeks after germination, but if a pre-emergence herbicide (this a chemical used to subdue weed) is used, the first weeding should be 4 weeks after. It is best to complete weeding by the 6th week, when the crop is already covering the ground. The two types of parasitic weeds that affect Cowpea are Striga and Alectra.

Disease Control

Cowpea is affected by a variety of diseases &-8211; fungal, bacterial and viral disease and these affects cowpea in different ways at different stages of growth.

Root Rot is caused by fungi, due to either damp weather or too much of moisture in the soil.

Stem Rot is caused by Phytophthora vignae, it occurs mainly in wetter coastal and sub-coastal areas, also occurs on waterlogged soils.

Mosaic virus affects leaves, the infected leaves are smaller than the healthy ones, and edges of the leaf are curly, generally the infected plants are more dwarfed and bushy, than non-infected plants. The disease also affects the formation of the pod.

Fusarium Wilt affects the leaves, it causes the lower leaves on one side of the plant to turn yellow, and plants infected are usually stunted and wilted. In order to control Mosaic virus and Fusarium Wilt it is s best to plant tolerant or resistant varieties. Although in the case of Fusarium Wilt root-knot nematode control practices should be followed since nematodes increase plant susceptibility to Fusarium wilt, and Cowpea is susceptible to nematodes, so it should not be planted consecutively on the same land. Other major and common diseases of cowpea are Anthracnose, Sclerotium stem, Damping off, Cercospora leaf spot, Septoria leaf spot, Scab, Bacteria blight (Xanthomonas vignicola) etc.

Some general control measures include:

  • Plant only unaffected seeds
  • Use a resistant variety
  • Remove and bury infected plants
  • Make use of Crop rotation
  • Apply chemicals (fungicide and herbicide)
  • Topsoil that have been contaminated should be ploughed to reduce the incidence of pathogens
  • Treatment of seeds


Pest control

Cowpea is attacked by various Insect pests, during different phases of its lifecycle even down to storage. This is a major constraint to Cowpea production especially in West Africa, because their damage can be as high as 80-100% if not well managed.


These are some of the major and important pests of cowpea :

Aphid (Aphis craccivora) &-8211; This insect pest does not just cause direct damage to the Cowpea, it also acts as a vector in transmitting of Cowpea aphid-borne mosaic virus. It damages the plant by sucking sap from the under surface of young leaves and stem issues, and on the pods. Sometimes it is recommended, not to control the insect pest until it is considered large i.e.when its infestation is threatening the crop, but if its few they can be easily pulled out, burnt or fed to livestock. The decision to treat is based on visual counts and the stage of crop development. Commercial pesticides are used to control aphids and the most effective are systemic pesticides, also heavy rains do reduce aphids.

Thrips (Megalurothrips sjostedti) &-8211; This pest attacks the flowering stage of cowpea. It can cause complete crop loss and in some cases where infestation is severe plants do not produce flowers or flowers appear distorted and discoloured, flower buds and flower can fall prematurely in some cases without forming any pod. This insect pest can be controlled by using insecticide or recommended chemicals.

Pod sucking bugs (Anoplocnemis curvipes): This pest attacks the pods of Cowpea. It causes a yield loss which varies from 30% to 70%,.They suck the sap from the green pods, causing them to shrivel and dry prematurely, which results in seed loss. It can be controlled using pesticide during podding period.

Cowpea weevil (Callosobruchus maculatus): It’s a serious Cowpea pest  which affects it in during the storage period,. it can completely destroy the grain within 6 months, although it’s considered medically harmless to humans. Hermetic storage (process of removing oxygen present in the atmosphere) technologies can also aid in controlling the pest. Freezing also can help control the pest.



Cowpea should be intercropped or mixed cropped and also grown as a cover crop for average yields to be attained. Cowpea should be harvested when the pods are fully mature and dry, but these pods do not mature at the same time because of its staggered flowering period. Cowpea varies in its growth habit from erect to semi erect types. Cowpea that is grown for vegetable purposes are picked 4 weeks after planting. One can either use hand or combine harvester to harvest the crop. More than 11 million hectares are harvested annually worldwide, 97% is from Africa and Nigeria harvests 4.5 million hectares annually. After harvesting, it is best to sun dry the pods and then thresh them immediately. This is important because drying reduces the moisture content of the grains, before storage in order to avoid the seed getting mouldy.


After drying the seeds to about 10% or less and threshing the seeds, pods should be stored. It is advised to store the seeds using Hermetic storage techniques, the store should be cleaned before loading in new seed and also the seeds should be sorted before storing.


Economic Importance

IITA (2009) noted that there is a big market for the sale of Cowpea grains and fodders in West Africa and in Nigeria farmers who store Cowpea fodder for sale at the peak of the dry season have been found to increase their annual income by 25%. It also serves as income generating avenues for other value chain actors within the cowpea chain. Cowpea ensures returns for both the marketers and producers which in turn aids sustainability of the system.



About 5.4 million of tons of dried cowpeas are produced worldwide from 11 million hectares, Africa produces nearly 5.2 million and Nigeria harvests 4.5 million hectares annually.

Nigeria is the largest producer of Cowpea worldwide, as 58% of worldwide production comes from this country yet Nigeria is still the largest consumer of the crop. To supplement our production, substantial amounts of Cowpea come into Nigeria from Cameroon, signifying that we are still not producing enough Cowpea to feed our nation.

In most parts of Nigeria Cowpea is been processed into other by products such as moin-moin, bean cake, bean soup etc. It contains 20%-25% of protein and 64% carbohydrate and has potential for poverty alleviation and malnutrition amongst the poor; also all parts of cowpea are useful, its vegetative part is good feed for cattle. This shows that all over Nigeria Cowpea is consumed in so many forms, thereby increasing the demand for cowpea.



COWPEA: Post-Harvest Operations culled from (PRODUCTION GUIDE ON COWPEA)



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