Ghana: Yam Dioscorea

Yam Dioscorea Summary Fact Sheet

Average National output (past 5 years), MT 2016-2020

8,236,400 MT


Total area under Cultivation (Ha) 2020 growing season

505,000 Ha  


Planting Time

Guinea Savanna, Transitional and Forest Zones (December - March)

 Coastal Savanna Zones (January)

Planting Distance

1m x 1m

1m x 1.2m

Different recommended plant distances depending on the variety and locality. 

The recommended planting distance is 1m x 1m or 1m x 1.2m, resulting in 8000 to 10,000 stands per ha

Density (Plant population per ha)

1m x 1m (10,000)

1m x 1.2m (8,333)

Fertilizer Application Rate per Ha

6-8 bags of NPK per hectare or (1-2 crown corks per stand) per hectare in two split applications at 5WAP and 8-10WAP – all spot placement) OR

Apply 3-4 bags of NPK per hectare 4 weeks after planting and 1.5 bags of urea and 1 bag of Muriate of potash mixed as second application at 16 weeks after planting – spot placement and covered.

Organic Fertilizer

- Cow dung – 3 tons/ha.

- Poultry manure – 4 tons per ha.

- Compost – 5 tons per ha.


Potential Yield per Ha

52,000 Kg/Ha 

Achievable according to research when farmers follow the production protocol.

Average Yield (2020)

17,500 Kg/Ha


Budget Benchmarks
Costs for Establishment per Ha

GHS 27,010.00 (Ridging)

GHS 26,510 (Mounding)

Cost of land purchase or hiring is not inclusive.


Estimated Revenue per season

GHS 51,100

Using a yield of 17,500 Kg/Ha and 250kg of yam costing GHS 730.50.00 (the sales of ware yams only)


Average Gross Margins per ha per season

GHS 24,090 (Ridging)

GHS 24,590 (Mounding)

Profit margins from establishing a hectare of yam field. This is calculated from the average cost scenario.


General Overview of Yam Production

Yams are starchy staples in the form of large tubers produced by annual and perennial vines grown in Africa, the Americas, the Caribbean, South Pacific and Asia. Yam, a multi-species tuber crop of the family Dioscoreaceae, is considered one of the most important staple food crops to about 400 million people in West Africa and provides a valuable source of dietary carbohydrate and income to growers (Bhattacharjee et al. 2011; Nweke 2016). World production is estimated at 73 million tons, with West Africa producing more than 93% of the crop (FAOSTAT 2019). Nigeria, Ghana, and Ivory Coast together produce about 86% of the world’s yam supply. Ghana’s production output is approximately 12 per cent of global output. This production figure is projected to increase by the close of 2021, due to its importance in the National Economy. 

In Ghana, yam (Discorea sp) is an important staple food crop and it is produced throughout the country. Ghana is the leading exporter of yam, despite the fact that it is the second largest producer in the world, after Nigeria. Average annual consumption of yam is about 230 kg per capita (MOFA-SRID, 2020), and it is the third most important source of energy in the Ghanaian diet, accounting for 20 per cent of total caloric intake (FAO STAT, 2012). 

In 2020, yam production totalled 8.95 million metric tons with a corresponding area planted nationwide being 505,000ha. The average yield on-farm for the commodity is 17.7 Mt/ha but has a potential of up 52 Mt/ha. Studies have shown that, this productivity can be improved. Proper use of agro-chemicals and high yielding certified seed or improved varieties as well as employing mechanization and good agronomic practices can result in improved productivity. 

Currently, there are seven (7) high yielding improved varieties developed by the Crop Research Institute (CRI) of Council for Scientific and Industrial Research (CSIR). The varieties including, (CRI-Pona, CRI-Mankrong Pona, CRI-Kukrupa, CRI-Soanyinto, CRI-Afase Biri, CRI-Afasepa and CRI-Ahoodinfoo) have different uses (Table 1). However, these are insufficient to meet the different needs and the growing demand for improved varieties to satisfy the emerging markets. Hence the need to develop and disseminate more superior varieties.

Table 1: Varieties of Yam in Ghana

VarietyOriginDistinctness uniformity and stabilityValue for cultivation and usePreferred EcologyYear of Registry

Young Stem: young stem colour: Purple Green; 

Mature leaf: colour: Dark Green; Mature leaf: 

petiole length (cm):5; Petiole length in correlation to leaf blade:

Cylindrical tuber shape: Roots on tuber surface; no Spine on tuber


Potential yield: 42 Mt/ha.

Dry matter content:33%; 

Crude ash: 3.37%

Crude Protein: 2.5%

Solubility: 13%

 Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah

 Mankrong-pona IITA,Ibadan

Young Stem: young stem colour: Brownish Green; Mature leaf: tip coloor: Dark Green; 

Petiole wing colour: Green with purple Edges.

Cylindrical tuber shape: no roots on tuber surface; no spines on tuber.


 Potential yield: 70 Mt/ha.

Dry matter content:34.63%; 

Crude ash: 3.01%

Crude Protein: 8.67%

Solubility: 11.33%

 Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah

 CRI-Kukrupa Landrace/Ghana

Young Stem: young stem colour: Green; Mature leaf: tip colour: Dark Green; 

Petiole wing colour: Green.

Cylindrical tuber shape: roots on tuber surface; spines on tuber:no


 Potential yield: 50 Mt/ha.

Dry matter content:33.42%; 

Crude ash: 3.37%

Crude Protein: 9.39%

Solubility: 13%

Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah

 CRI-Afase Biri Landrace/Ghana

Colour of young leaves: purple; colour of older leaves:Dark green with purple tinge.

Characteristics:Light green with purple nodes and purple wings

 Purple tuber flesh;Yield is 43.7Mt/ha; virus tolerant; nematode:

Bacterial Leaf Blight:Tolerant

Uses: Ampesi and fufu

 Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah

 CRI-Soanyinto Landrace/Ghana  

 Colour of young leaves: light green; colour of older leaves:Dark green; distance between lobes: wide

Characteristics:green with green wings 

Yield is 30.3Mt/ha; virus tolerant; nematode: tolerant

Bacterial Leaf Blight:Tolerant

Uses: Ampesi and fufu

Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah

 CRI-Afasepa IITA,Ibadan

 Colour of young leaves: Greenish with purplish tinge; colour of older leaves: green; distance between lobes: no distance

Characteristics:Green with dark green wings 

 Yield is 32.3Mt/ha; taste good: virus tolerant; nematode: tolerant

Bacterial Leaf Blight:Tolerant

Uses: Ampesi and fufu

 Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah


Colour of young leaves: Green; colour of older leaves: green; distance between lobes: wide

Colour characteristics:Green with green wings 

Yield is 34.6 Mt/ha; virus tolerant; nematode: tolerant

Bacterial Leaf Blight:Tolerant

Uses: Ampesi and fufu

Coastal savannah, Forest, Forest-savannah

Transition and Guinea savannah


Currently, there are seven (7) high yielding improved varieties developed by the Crop Research Institute (CRI) of Council for Scientific and Industrial Research (CSIR). The varieties including, (CRI-Pona, CRI-Mankrong Pona, CRI-Kukrupa, CRI-Soanyinto, CRI-Afase Biri, CRI-Afasepa and CRI-Ahoodinfoo) have different uses. However, these are insufficient to meet the different needs and the growing demand for improved varieties to satisfy the emerging markets. Hence the need to develop and disseminate more superior varieties.

For the past decade, yam production accounted for about 29 percent of total roots and tubers production in the country (MoFA-SRID, 2020). The distribution of yam production throughout the country is largely dependent on rainfall patterns. Yams require at least five months of rainfall (Orkwo & Asadu, 1997), as well as in fertile soils (Sagoe, 2006). Yams generally grow better in areas where annual rainfall ranges from 1,000 to 1,500 mm and is well distributed over six to seven months of the growing season.

Despite the great importance of yam to the country’s economy, its production is stagnating and thus threatening rural livelihoods and urban food security. It is the most expensive of the root and tuber crops to produce because of the high labour demands for land preparation, planting, staking, weeding, harvesting and transport to market. Also, planting material (seed yam) is expensive and in short supply because of the low multiplication rate of yams (Aidoo et al; 2011). 

Apart from the above, a number of constraints affect the efficiency of the entire value chain. Pests and diseases, declining soil fertility and poor agronomic practices (such as indiscriminate use of agrochemicals), reduced yields on farmers’ fields across the country. Tuber rots also contribute significantly to post harvest losses that affect competitiveness of the export trade. Poor postharvest handling and inadequate infrastructure across the value chain affects the potential of the crop to contribute significantly to the GDP of the country.

Yam is one of the five priority crops earmarked for promotion in Ghana’s  Medium Term Agriculture Sector Investment Plans, which details the roadmap for the Comprehensive African Agricultural Development Programme in the country.


Value Chain mapping and Key Actors

The yam value chain in Ghana comprises a range of stakeholders, including yam tuber or seed farmers, aggregators, producers, processors, exporters and transporters, as well as companies that provide support services. The government is another actor in the value chain creating an enabling environment for the smooth running and strengthening of the chain.

The value chain mapping gives an idea of the different activities experienced within the yam value chain, starting with the level of inputs, production stage, transportation, wholesale/retail, and down to the processing level. The value chain hinges on the research carried out at various levels within the chain in the country.

In Ghana, yam is generally traded in its original state (Bancroft, 2000) and is not processed into a secondary product. Traders and chop bar owners (small restaurants) often buy yam to sell or prepare for consumers directly. Yam for the export market is also not processed, but is treated, wrapped in newsprint and packed in 25 kg boxes before it is shipped. The value chain for yam is less developed than the value chains for other commodities in the country, such as rice or maize. Although there has been considerable support for yam farmers, the value chain is still weak with respect to linking farmer organizations to market associations and ensuring that producers do not lose in production. 

Regarding market links, yam produced in the Northern Region is generally transported to Accra through the eastern corridor; either through Hohoe and Akosombo or through Kete Krachi in the Volta Region. Yam from the Northern Region is also transported to Kumasi, either through Yeji, Atebubu and Ejura or through Tamale. While the first route to Kumasi is only about 270 km, compared to 509 km from Tamale to Kumasi, it is unreliable due to the irregularities of the Volta Lake ferry crossing at Yeji. Yam from Brong Ahafo are generally transported to markets in Techiman, Kumasi or Accra. 

Key activities across the yam value chain

Source: Sahel Capital’s Field  Research, 2014


Key Pests & Diseases, Symptoms and Control Measures


Pest/ DiseaseSymptomsControl / Management
Major Pests  


Yam tubers infested by nematode           
Severe galling due to nematode attack

Infected tubers show dry rot of 1 to 2 cm. Initially, this dry rot is of cream and light-yellow lesions appear just below the outer skin without any external symptom.

With progress in disease, lesion spreads deeper (maximum up to 2 cm).

At later stage the rot become light and dark brown to black in colour and tubers may show external cracks.

Entry of fungus through this wound causes further decay of tubers in storage.

There is no above ground symptom with yam nematode infestation.

Sometime, the infected tubers may not show external cracking which make it difficult to diagnose.

  • Use disease free tubers/setts for planting.
  • Treating tubers with hot water for 40 min at 50-55 0C before sowing and after harvest to reduce disease both in field and storage.
  • Smearing tubers with wood ash also could reduce nematode infection in field.
  • Follow crop rotation with non-host or antagonist crops like ground nut, sorghum, maize, chilli pepper etc.
  • Scrap out the external layer of tuber to check the disease incidence in there is no external cracking .

Mealybugs Rastrococcus spp.

Insects have a wide host range; often tended by ants which  for their sugary honeydew secretions.

They cause damage to tubers by sucking the sap from their tissues.

Mealybugs on yam (credits: CABI)

Flattened oval to round disc-like insect covered in waxy substance on stems; insects attract ants which may also be present;

insect colony may also be associated with growth of sooty mold due to fungal colonization of sugary honeydew excreted by the insect

 Prune out heavily infested branches;

chemical pesticides may decrease populations of natural enemies leading to mealybug outbreaks;

Practice crop and land rotation with cereals (e.g. maize, rice, sorghum or millet) to reduce risk of field infestation

Situate yam farms away from previously infested fields to avoid carrying mealybugs into storage

Mealybugs are a problem in prolonged storage of yams. Monitor mealybug populations after 3 months of storage

Inspect twice a week by looking out for white powdery mass on the surfaces of tubers

Take action when at least one tuber is infested

The insect prefer warm humid conditions and spread by crawling between tubers, avoid heaping of tubers to allow light and air through

Spray harvested tubers or yam plants with a steady stream of water (reasonably high pressure) on the host plant to knock off mealybugs

Use horticultural oils or soapy solutions can be used to treat heavy infestations. Spray soap solution (potassium soaps e.g. "alata samina","gardian") (add 10-15 tablespoons of liquid soap in 16 L Knapsack and spray on tubers if infested when necessary)

Treat yam tubers with neem seed extract. Rate: 1 match box of dry seed/1litre of water



 White Scale insects Aspidiella hartii

The scale insect damages stored yams. Large numbers turn the yams light grey. The scales have long tube-like mouthparts that pierce the skin of the yam tubers and feed on the flesh beneath. The scale is an armoured species, so-called because it makes a hard covering over its body. 

This is a common insect on stored yams in all countries where it is recorded.

Colony of Aspidiella hartii
White scale insects infested yam tubers


 When large numbers of scales are present the yams become fibrous or shrivelled tubers and this affects their quality. 

 Cultural Control  

  • Check the surface of yams before they are stored.
  • Inspect yams in storage regularly, and remove those that become infested with the scale.
  • Select tubers that are free of scale insects for planting.

Chemical Control  

  • Use white oil (made from vegetable oils), soap solution or horticultural oil (made from petroleum) on yams infested with scale:
  1. after harvest and before yams are stored;
  2. during storage, on yams when infestations begin; and
  3. at the time of planting before the tubers are cut


  Yam Leaf Beetle (Coleaptera: Chrysomelidae: Crocernae) 

They are small sized beetles with hard elytra

  • They feed on leaves and tender growing points causing vine die-back, ragged leaves and total defoliation.
  • They result in growth retardation and loss of stands resulting in tuber yield reduction
  • Destruction of eggs on the oviposition site
  • Plucking larvae infested leaves and tips of vine for destruction
  • Killing the adults found on the leaves
  • Good tillage system that expose the soil to solar radiation can cause appreciable mortality of the beetles
  • In severe cases, use insecticides but not as routine
  • Very late planting can reduce infestation but affect yields.
  • One can use isotope and radiation of lightning devices to trap the beetles during their migration.



 Major Diseases  

Anthracnose / ‘Scorch die-back’ 

This is a fungal disease.  Disease hibernates in plant debris; occurs worldwide. It is a major disease during the vegetative growth period. The symptoms range from leaf necrosis to complete defoliation.

Anthracnose symptoms on yam foliage
  • Small, dark brown spots or black lesions on leaves which may be surrounded by a chlorotic halo; leaf necrosis; dieback of stem; withered leaves and scorched appearance.
  • The disease can attack all parts of the yam plant at all stages of development. Infections concentrated or expressed on the shoot tips generally result in vine and/or tip die-back.
  • Severe infection results in defoliation leaving naked, black and drying vines. Shoot tip and stem die-back frequently occur under such severe infections.
  • The disease reduces the effective photosynthetic surface of the plant and is particularly serious when it attacks the plant immediately after tuber initiation or during bulking.
  • The most effective method of controlling the disease is to plant yam varieties that are resistant to anthracnose to minimize the incidence of the disease.
  • Apply an approved fungicide where and when necessary.

Yam mosaic disease (Yam mosaic potyvirus)

This disease is caused by a virus. The virus is transmitted by aphids and tubers/setts. It may cause up to 40% loss in yield. Yam mosaic virus is always associated with yam mild mosaic virus, yam badnaviruses and cucumber mosaic virus in Africa making this disease more complex. Disease is reported in West Africa, South America and Caribbean.

Yam mosaic virus infected plant

Onset of viral disease    
Severe stage of viral disease
  • Infected leaves show yellow and green patterns (called mosaics) between the veins or may show a narrow green strip bordering the veins (called vein banding).
  • In  severe cases the leaves become long, thin and strap shape (called shoe-string symptom) and whole plant become stunted.
  • Plant may produce few small tubers with less starch content.
  • Some plants may recover from the virus infection soon after first symptom but virus may survive in plant and reduce the vigour.
  • Use healthy and disease-free tubers or setts for planting.
  • Select healthy and large tubers for planting instead of small tubers.
  • Keep fields free from weeds. Collect crop debris and destroy them.




Key Agronomic Practices and their Importance

Good Agricultural PracticeBrief Description and Importance

Planting Material/ Variety Selection

Yam is propagated vegetatively using clean and healthy tubers from any of the following:

  1. small whole tubers selected from previous harvest
  2. Cut-pieces of seed yams from milked yam
  3. macrosetts of 500-1500 grams generated from 50 grams setts (minisetting)
  4. microsetts of 20-30 gram generated from 2-node vine cuttings
  5. junked setts of 300-1500 grams generated from ware yams and pre-germinated by burying them in trenches to cure.

The head region of yam sprouts faster than the tail and the tail faster than the middle portion. These regions may be grouped and planted differently to enhance uniform growth. Sett size for planting is positively related to the expected yield of the yam. 

The choice of variety is influenced by utilization and market demand. Over 80% of cultivated yam species in Ghana are in the white group. Seven improved yam varieties (CRI-Pona, CRI-Mankrong Pona, CRI-Kukrupa, CRI-Soanyinto, CRI-Afase Biri, CRI-Afasepa and CRI-Ahoodinfoo) are available for cultivation. There are also available several local landraces that are cultivated and consumed in Ghana. The improved varieties are currently being recommended for cultivation by farmers in Ghana. 

The average yield potential of the landraces is 15MT/ha compared to the 50-60MT/ha of improved varieties.

Examples of Some key local landraces/ varieties in Ghana.

Pona , Lariboko, Dente/Ponjo, Muchumudu/Moonye/Asana/Araba/Moninyo, Akaba, Matches/Seidu Ble, Serwah/Afebetua, Maamakumba, Lelee,Lobare/Dorban, Asobayere/Auntie Akosua, Nooma, Akwa, Kwasekohwe  ,Nanato, Enkanfo and Chinchinto.

Planting material Preparation

Planting material or seed yam is usually a limiting factor in the expansion of yam cultivation. It is expensive and often scarce.  

Below are planting materials used for yam cultivation and how they are generated:

  1. Small whole tubers selected from previous harvest
  2. cut pieces from seedyams of milked yams
  3. macrosetts of 500-1500 grams generated from 50 grams setts (minisetting)
  4. microsetts of 20-30grams generated from 2-node vine cuttings
  5. junked setts of 300-1500grams generated from ware yams and pre-germinated by burying them in trenches to cure.

Small whole tubers

Small whole tubers weighing up to about 1000grams may be selected from the harvest and use as planting stock. This is often the preferred planting sett because it has a complete skin covering giving it a better protection from pest and diseases. One should however exercise caution when using such small tubers because such tubers may be small because they are diseased.

Cut pieces from milked yam

Seed yams often have irregular shape and may have several small tubers fused together. Some of these small fused tubers may weigh up to 500grams when separated. These small separated tubers could be planted to generate ware yams.


Seed yam showing several small tubers fused together


Minisetts often are up to 50g yam pieces obtain from ware yam or seed yam for planting. Depending on the variety, yams weighing up to 2.5kg could be obtain from such small pieces. However, it is often common for most varieties to obtain yam tubers weighing between 500-1500g, known as macrosetts. These macrosett could be used to plant to generate ware yams. Such seed setts also have the advantage of small whole tubers of having a complete skin cover.


Smaller yam pieces tubers weighing 20-200g could be obtained from 2-node yam vine cuttings. Depending on the variety, such small whole tubers could produce 2.5kg ware yams when planted.

Microtuber 20gram


Microtuber 200 gram

Junked setts

Yam setts are obtained by cutting ware size tubers into tops, middles and bottoms. Sometimes the tuber is sliced from head to tail The tuber could be cut into 4 or more pieces (depending on size of tuber), and also re-buried in the same mound. They are harvested along with the second harvest in November/December. During the second harvest in November/December, the resulting tuber usually comes in a multi-tuber sett and could be cut into several smaller yam setts for next planting.

Harvested junked setts ready for planting

Choose suitable soils

Yams require loose soils that allow easy penetration of the tuber. Select gently slopped lands with deep, and well-drained soils rich in organic matter and with a pH between 5.5 and 6.5 in full sun or part shade for optimal growth. Yams grow optimally in well-draining fertile soils. Very wet soils should be avoided as this promotes tuber rot. Also avoid waterlogged, extreme sandy or heavy soils (clayey). Clayey soils are prone to water logging. The soils crust and crack when dry, and damage the rooting system. 

Sandy soils do not retain water after rain or irrigation and expose plants to drought stress, which can cause total crop failure depending on the crop’s growth stage and duration of the drought. 

Agro Climate Conditions

Yam is well adapted to a wide range of climatic conditions. In Ghana, yams best thrive in Guinea Savanna, Transitional, Forest Zones and Coastal Savanna agro-ecologies. They are annual rain fed crops which grow for 6-12 months depending on the cultivar, ecology and soil properties in the production area.  

The optimum temperature for the growth of yams is between 25 and 30°C and optimal annual rainfall of 1,000-1,500mm for a good yam growth and yield.

As a general rule, consider the following in selecting a site for yam production:

• Cropping history – disease/pest prevalence

• Topography – flat to gentle undulating slope

• Soil Type – deep, loose, fertile soil

• Accessibility  

Land Preparation

Good land preparation is critical for sprouting and plant establishment. It also reduces weed competition. Prepare the land by clearing (slashing/herbicide application/ ploughing) followed by mounding or ridging. Traditionally, mounding is the main practice by farmers (picture A) however, for commercial or large scale production, ridging (picture B) is recommended for optimum plant population and high yields.  Ridges or mounds should be 45 cm high, constructed in rows, 1 m apart and the plots well mulched (picture C).

Picture A: Mounds for planting yams
Picture B: Ridges for planting yams
Picture C: Ideally prepared lands should be mulched


 field. Planting dates should fit with local farming calendars. This ensures healthy sprouting and good crop establishment. Plant timely when rains have stabilized. Planting period may differ according to the farming system, agro-ecology, maturity group of variety planted and/or season. In the Guinea Savannah zone, some varieties especially white yams are planted in November to December and allowed to break dormancy in the mound/ridge before sprouting at the onset of the rains.

Yam setts are planted by burying in mounds/ridges and covered with mulching material to conserve moisture in the soil and enhance sprouting.  

The recommended planting distance is 1m x 1.2m or 1m – 1.2m x 1m – 1.2m, resulting in 8000 to 10,000 stands per ha. Planting in rows at recommended spacing ensures:  

  • Optimum plant population.
  • Effective control of weeds, pests, fertilizer application and harvesting.


  • Ensure planting setts are treated with recommended fungicide/insecticide and air-dried before planting.
  • Ensure that the back surface of cut yam setts are in contact with soil (with cut surface facing up).

Yam Cropping Systems

Mono/ Sole -cropping

Yam is commonly grown under sole cropping by medium to large scale farmers but small-scale farmers sometimes intercrop with cereals and legumes. Sole cropping is advantageous because the correct plant population per unit area is achievable. In addition, it is easier to mechanize field operations in sole cropping systems. This makes sole cropping more compatible with large-scale production systems. Cultural practices such as, weed control and pesticide application are much easier in mono-cropping system. However, in the event of an outbreak of diseases and insect pests, total crop loss may occur.


Farmers usually intercrop legumes and cereals with root and tuber crops in many areas of Ghana. The leguminous crop has the capacity to enrich the soil with nitrogen. Some farmers use the leguminous crops as either cover crop or plant and plough them into the soil as green manuring.

The yam/maize intercrop provides an example of the presence of the competition gap, within the period each crop makes maximum demands on the growth factors (soil-moisture, soil nutrients, light etc.) resulting in higher total yields than the sole crops (Okigbo and Greenland 1976). Intercropping has been shown to have several advantages such as better utilization of environmental factors, greater yield of food, increasing the return per unit area and insurance against crop failure (Silwana and Lucas 2002). 

Yam/soybean or cowpea intercrop is also highly productive system and is recommended. This system has the potential to give comparable yields to those of sole crop yam with the soybean yields as bonus.

Crop rotation

Two or more crops grown alternately on the same land can result in significant yield improvement. Yam is a favourable crop after maize, soybean, and sorghum. The success of this system depends on the choice of crops, use of suitable varieties, cropping sequence and management practices.

Advantages of crop rotation include:

  • Improved soil fertility
  • Complementary use of nutrients
  • Better pest and disease control
  • Organic matter restoration and
  • Improved soil physical properties.

 Staking of Yam Vines

 Yam is a climber and needs to be staked. Stake yams individually or construct trellis. The height of either the stakes or the trellis must be about 2m high. Avoid the use of tall stakes or trellis. Bamboo is an excellent material that can be used if available. In intensive yam cultivation systems, live stakes are preferable.  

Stake white yams 4-6 weeks after emergence to prevent the growing tip from dying off and induced multiple vine development.  

Where stakes are not available, the vines must be gently coiled following the natural twining direction to form a cover on the mound.  


 Pest and Disease Management

 Mealybugs Rastrococcus spp, White Scale insects Aspidiella hartii, Yam Leaf Beetle (Coleaptera: Chrysomelidae: Crocernae) and Nematodes are the major insect pests of yam in Ghana.  

These pests can cause considerable damage to yam and therefore reduce crop productivity. They must therefore be effectively managed through an integrated approach to optimize crop yield.

The major diseases of yam are:  

  1. Anthracnose / ‘Scorch die-back’
  2. Yam mosaic disease (Yam mosaic potyvirus)

These diseases prevent farmers from getting optimum yields. To control or manage these diseases,

  • Plant improved (tolerant) yam varieties
  • Plant clean, healthy materials
  • Practice crop rotation
  • Plant at the beginning of the major season rains.

 Integrated Pest & Disease Management

This involves the utilization of a variety of methods and techniques including: Cultural, Biological and Chemical. It is based on prevention, monitoring and control. The best way to control pests is to grow a healthy crop and treat planting materials with appropriate insecticides.


Soil Fertility Management

 Yams are heavy feeders and respond to fertilizers (organic and inorganic). Lands of long cropping history with low fertility will require the application of fertilizers for good yields. Depending on fertility of soils, the following nutrient application regimes are recommended:

  • Apply 4-8 bags (1-2 crown corks per stand) of NPK 30-30-36 + 20 Mg +15 MgSO4 compound fertilizer per hectare in two split applications at 5WAP and 2 months after first application (Asumadu et al pers. communication). OR
  • Apply 3-5 tons of animal manure as basal application and top dress with 2-4 bags (0.5-1.0 crown cork per stand) of compound fertilizer.

NB: Include option for integrated nutrient management. It is essential to conduct soil tests to determine the nutrient needs of yam and make the appropriate fertilizer recommendations.

  • Soil of primary fields does not require mineral application. Lands fallowed for more than five years do not need fertilizer application.
  • In areas where ploughing is done, plough-in leguminous cover crops such as Mucuna to improve the soil physical and chemical properties.  Add manure such as cow dung or poultry droppings at land preparation.


 Weed Management

 Weeds compete directly with plants and reduces yield. Weed competition reduces vegetative growth and development as well as tuber bulking. Weeds also reduces the quality of produce, harbour pests and diseases, obstructs farming activities etc. Therefore:

  • Hand weed or apply recommended herbicides to control weeds
  • Hand weed using cutlass or hoe
  • Control weeds within the first 3 months
  • Combine different cultural practices for effective control of weeds

Practice of managing weeds that damage agricultural crops is very essential. Such measures include:

  • altering the planting dates
  • good agronomic practices and cropping system etc.
  • targeted use of recommended agrochemicals

There are several weedicides on the market with different rates of application. Examples are Glyphosate and Diuron. Care must be taken when using these chemicals. Please follow the recommended rates.  

NOTE: Weed on the average, 3 to 4 times before harvesting. Avoid the use of chemicals after the emergence of vines. Always use protective clothing when spraying. Weed control is most successful when it involves an integrated approach using a variety of methods.  


 Cover up mounds or ridges during weeding to avoid exposure of tubers to sunlight, rodents etc. This may become necessary with time as the rains wash mounds or ridges away.  

 Harvest Management

 Maturity can be detected when the leaves turn yellow to brown. Some white yam varieties (pona and laribako) may be harvested two times. The first harvesting (for ware yams) usually called milking can be done between five and six months after emergence. Milking also provides the opportunity to generate seed yams. The second harvesting usually for seed yams is done between two to three months after the first harvest. Otherwise harvest once in seven to eight months after emergence.  

Other late maturing yams (like Dente, Serwa and Muchumudu) may be harvested between 10 and 12 months. Avoid bruising of the tubers during harvesting to enhance the storage of the tubers.    


Harvest early or at the right time to avoid field losses. Timely harvesting and post-harvest operations in yam is very important to maximize yields, minimize postharvest losses and quality deterioration.  

Harvest yam either manually (by hand) or mechanically (by machine e.g. harvester). Yam harvester is efficient on ridges and when the weather and soil conditions are dry.

Manual Harvesting

In Ghana, most farmers harvest yam manually because their farms are usually small (0.25 to 2 ha) and also practice mixed or inter-cropping.  

Mechanical Harvesting

Commercial large-scale farmers use yam harvester on their fields. This practice is advantageous because it saves time and reduces the drudgery farmers go through to harvest.

Post-Harvest practices 

 Yam storage duration depends on the yam variety, but also on the quality of the storage facility.

On average, most farmers can store yams for up to 5 months, but the pona variety cannot last for more than 3 months.

Storage protects the quality of produce from deterioration thus the storage environment for yam and its processed products should be cool and dry to avoid accumulation of moisture to prevent or slow deterioration.

Yam stores better in well ventilated environment. Several storage structures that encourage ventilation and prevent rodents are used.  

Store healthy (clean and undamaged) tubers in yam barns, on wooden shelves or cribs with good ventilation and adequate shade.  

In some cases, tubers may be stored in the ground by delaying harvesting. Traditionally, some farmers store harvested ware yams in the soil.  

Inspect regularly yams in storage to remove rotten, and scale insects attacked tubers.  

  Pre- and Post-Harvest Losses

 Yam production and storage involves a high level of pre and post-harvest losses. During the cultivation period of yam in the farm, yams are attacked by pests and diseases (pre-harvest losses).

Post-harvest losses in the yam value chain largely occur at several stages including the harvesting process, on-farm storage, marketing and consumption as well as during export.


 Raw yam could be processed into chips or flour. Often due to the high value of white yams such as Pona and Laribako varieties it makes it uneconomical to process yams in into flour.

Processors use water yam for processing high quality yam flour and amala given that it is relatively cheaper than the white yam varieties. In addition, the research community, including CRI, have commenced research into alternative uses of specific water yam varieties.

New product introductions by the Food Research Institute and percentage of yam in tghe products.

Yam flour for pounded yam 60 - 80%

Yam bread 20%

Yam cookies 40%

Yam cake 20%

Yam balls 40%

Vacuum packed yam 100%

Frozen yam 100%



Market Information

Yams from Ghana are produced in large quantities and are exported throughout the whole year.  Ghana produces on average eight million tons of yam annually. Yam is a leading agricultural export commodity for Ghana. Ghana’s export of the commodity ranks sixth in the world, representing 10.3% of world exports in 2016. The main exportable varieties of the commodity are the following:

  1. Pona
  2. Larebako
  3. Asana
  4. Dente
  5. Muchumudu

Yam exports from Ghana totaled US$13,429,328 and US$11,490,801 in 2020 and 2021, respectively, while the corresponding volumes were 38,566 Mt and 34,786 Mt (GEPA,2021).

In 2022, the approximate price range for Ghana Yams is between US$ 0.47 and US$ 0.5 per kilogram or between US$ 0.21 and US$ 0.23 per pound(lb). 

Price Trends

SRID, MoFA                   A Rebased CPI with 2012 constant prices 


Policies and Programmes in Yam sector

West Africa Productivity Programme (WAAPP)2009-2018Supported roots and tuber research, planting material production and distribution nationwide. Supported the release and registration of four improved water yam varieties.
Roots and Tuber Improvement and Marketing Programme (RTIMP)2007-2014Supported roots and tuber research, planting material production and distribution nationwide. Supported the release and registration of three improved yam varieties.


Cropping Cycle in Yam


Agriculture in Africa Media LBG |  Email: