Cassava, also known as manioc, yuca or tapioca, is a shrub with tuberous roots. It is the third source of food calories in tropical countries after rice and maize. This Euphorbiaceae was probably produced from pre-Columbian times in Brazil, Guyana and Mexico then brought to Africa by the Portuguese navigators.
Cassava is used in both human and animal food, in many industrial sectors, particularly in the form of starch, and more recently to produce ethanol. Cassava is primarily grown for its roots but all of the plant can be used: the wood as a fuel, the leaves and peelings for animal feed and even the stem as dietary salt.
The plant shows good resistance to drought, diseases and pests, and more particularly a very good yield.  One cassava plant can produce 5 to 6 kg of tubers whose weight varies from 100 g up to 3 kg. Nonetheless, due to their high water content (between 60 and 65%), the tubers are easily perishable, and so need to be processed near their production site, which is a major obstacle to their exportation. 
There are two main categories of cassava depending on their hydrocyanic acid content: sweet cassava (for direct consumption of the tuber) and bitter cassava (for making starch and other derivatives).  The demand for cassava by-products - starch, flour and chips - is increasing because they can be conserved for longer and their prices are often more competitive compared with other staple food products.
It should be noted that several research programmes are underway to create varieties that are resistant to diseases such as the Mosaic virus which causes the leaves to turn yellow and wither and limits root growth (it causes losses of 35 million tonnes  a year in Africa) or brown streak disease. The plant is also affected by rotting of the stem and the roots and by insects. 

Production 

World production of cassava is around 250 million tonnes (Mt) a year. After 15 years of uninterrupted growth and an increase of 13% between 2006 and 2009, it fell to 249 Mt in 2010 following a poor harvest in Thailand due to diseases and drought.
Africa contributes to more than half of global supply, with Nigeria on top, representing more than a third of African production alone (around 45 Mt); it is also the largest world producer by far. The Democratic Republic of Congo (DRC) follows with around 15 Mt, then Angola and Ghana (about 12 Mt each) and Mozambique (9 Mt). A staple food, contributing greatly to food security, the continent consumes almost all its production.
Unlike Africa, Asia encourages the development of cassava crops for industrial and energy purposes. This continent contributes to around a third of world production, with 60% produced by Thailand (around 25 Mt) and Indonesia (22 Mt). Vietnam and China are growing in strength and both produce between 8 and 9 million tonnes a year since 2008. India, now the 3rd cassava producer in Asia, is also experiencing continued growth in production with more than a 30% increase between 2006 and 2010.
In Latin America and the Caribbean production is relatively stable, around 35 Mt between 2006 and 2009, which represents almost 20% of world supply. Brazil dominates with some 70% of regional production and battles with Thailand, over the years, for second place in world production; the country should increase production following the increase in cultivated land area. Apart from Brazil, the two other important producers are Paraguay (around 5 Mt) and Colombia (1.5-1.7 Mt).

 Consumption

Worldwide demand for cassava by-products is on an increasing trend, but only Thailand, the leading world producer of cassava starch, is truly undergoing transformation towards industrial uses.
In market analysis on cassava by-products, rarely is a distinction made between cassava flour and starch; they come from the same cassava root starch but go through different phases of production.
• Cassava flour
The flour is obtained from drying the roots that have been cut into pieces: roots are washed, peeled, cut into chips, dried and milled. In Brazil, 70 to 80% of cassava production  is used exclusively for making flour.
• Cassava starch
Starch is a substance extracted from the tubers which must be processed within 48 of being harvested. By washing, peeling and grating, the grains of starch are liberated and then processed by soaking, successive sieving, centrifugation, pressing, drying and sifting before packaging.   The starch is used in many sectors, including the food industry, pharmaceutical chemistry, foundry, textiles, paper and adhesives. According to the FAO, overall an average of 60 Mt of starch is extracted per year from various cereals, roots and tubers, but only 10% of this starch comes from cassava. It should be noted that tropical countries import maize starch every year for more than $80 million, when often they could produce cassava starch locally.
In Latin America and the Caribbean starch extraction is developing slowly and it is estimated that the region only represents 4% of global cassava starch supply, preferring maize starch.
African countries have little or no presence in this processing sector, apart from Nigeria and South Africa : the continent consumes the roots fresh or after the first stage in their processing.
• Ethanol
Global production of bioethanol should, in general, reach 155 billion litres in 2020, i.e. 50% more than in 2011. Whilst cassava is still a small player on the biofuel arena, its role should increase considering the direction taken by China. In effect, with one tonne of cassava, which has a starch content of 30%, around 280 litres can be produced of 96% pure ethanol.
• Livestock feed
It is especially in Brazil and Colombia that cassava is used for animal feed; around half of production in Latin America is used for it, the rest being used to feed local communities and for exports to Nigeria, China, the Netherlands and Spain. Often the waste, such as leaves, stem bark and dried root skin are given to animals.

Trade

Only about 10% of global cassava production is traded. For the last ten years, flows into Asia have greatly accelerated and today Asia represents 98% of world imports and 97% of exports. It was in 2001 that cassava imports by developing countries exceeded those of developed countries for the first time. Since then, international flows have been concentrated on Asia, especially China.
The Asian continent is the biggest importer of cassava roots with 6.247 Mt of roots imported in 2010 out of a worldwide total of 6.392 Mt. China alone represents more than 92% of Asian imports, its purchases having tripled since 2001, and regularly each year with the exception of 2008. Besides its imports, China has boosted its own production which has doubled in five years to reach the current level of around 8 Mt. This interest in cassava can be explained by the stimulation of the ethanol sector: today China is the third producer of ethanol in the world behind the United States and Brazil. The decision at Beijing in 2007 to no longer use cereals to produce biofuels so as not to undermine its food security has undoubtedly boosted demand for cassava. Currently, 50% of ethanol production comes from cassava and sweet potato. 
The European Union, which for a long time was the main destination for global exports of cassava, mainly in granular form for animal feed, and which applies annual tariff quotas for the import of cassava and cassava starch, has become a small player, with import volumes which fluctuate according to the European cereal market. Since 2009, the abundance of Community supplies of feed grain has contributed to the reduction in imports.
Thailand, leading global exporter of cassava, dominates the market. Each year it exports around 4 Mt of roots, with the exception of 2008, and around 4.5 Mt of chips in 2010, of which 4.4 Mt were destined for China.  Volumes are also relatively stable in Indonesia with 145 000 t of cassava exported while Vietnam and, to a lesser degree, Cambodia have recorded significant increases in their exports: in Vietnam, they increased from 304 000 tonnes in 2006 to 1 Mt in 2010. As for Cambodia, whose exports were almost inexistent before 2008 when the country started producing ethanol, they amounted to 345 000 tonnes in 2009 and 128 000 tonnes in 2010. Nonetheless, for both these countries the FAO highlights that environmental concerns are more and more present.
Beyond Asia, Costa Rica (92 000 tonnes exported in 2010) mainly supplies the American market (70% of exports) whilst Paraguay exports exclusively to Brazil. In Africa, Uganda is the only African country which is characterised by its exports to Burundi, Rwanda and the Democratic Republic of Congo. As for the Netherlands and Spain, they save part of what they import to sell on to other members of the European Union.

Prices 

Like many other raw materials, export prices for flour and starch in Thailand (FOB Bangkok), the reference price, have increased, particularly during the second half of the last decade. Over the last eleven years, they have increased threefold, from $146.15 per tonne in January 2000 to $509.21 per tonne in May 2011, with an all time high recorded in August 2010, of $630 per tonne, following a bad harvest in Thailand. Since then, prices range from $500 to 600 per tonne. 

Traditionally, starch export prices from Thailand are competitive compared with maize, wheat or potato flour. The price for chips bound for China (FOB Bangkok) follows the flour/starch curve but to a lesser extent and did not soar in August 2010. As for prices within Thailand for cassava roots, they went from $57.2 per tonne in 2008 to $41.4 in 2009 and $76.1 in 2010.

Food issues

Cassava, which is cultivated as a monoculture or in association with other food products, feeds 700 million  people in Asia, Africa and Latin America. In African ACP countries, cassava is a staple food, eaten as fresh roots or as products from the first stage of processing (gari, attieke, fufu, tapioca, lafun…); its sale is also a source of income in urban areas. Cassava consumption was 115 kg per capita in 2010 in African ACP countries against 18 kg in the rest of the world.
Rich in carbohydrates but low in protein, the 2008 food crisis reinforced the African governments’ policy of developing the cultivation of cassava and promoting its consumption, particularly through mixing cassava and wheat flours for making bread. Besides its favourable characteristics, such as its high yields per hectare, its low need for inputs or its tolerance to drought, cassava has the advantage of being able to stay in the ground for more than a year and then being harvested in times of famine or cereal price rises. Its only handicap remains its fragility once harvested which prevents it from being easily transported.
In 2004, NEPAD (New Partnership for Africa’s Development) launched a pan-African cassava initiative (NPACI) whose goal is to increase the potential in Africa both for improving food security and generating income. Funded by the W.K. Kellogg Foundation and building upon national research systems and regional initiatives, it intervenes in the development of production and its processing. In this way, the International Institute of Tropical Agriculture (IITA), based in Ibradan in Nigeria, established a research project in 2009 for developing improved, but not genetically modified, varieties of cassava. The latest can have up to 6-7 tubers instead of the basic 2-3 tubers   with yields that are 30% higher, whilst being disease resistant.

References

(1) Le manioc, Laure Bichon, www.ledamed.org/IMG/html/doc-10011.html
(2) Food Outlook November 2010 
(3) Potentialités de nouveaux produits dérivés du manioc au Brésil, G. CHUZEL, N.ZAKHIA, M.P.CEREDA, 1995, éditions ORSTOM
(4) Etude de marché pour la commercialisation de la farine de manioc (Vanuatu) en Nouvelle-Calédonie, François JAPIOT, Avril 2009
(5) http://indices.usinenouvelle.com/matieres-premieres-industrielles/l-amidon-de-manioc-un-marche-a-forte-valeur-ajoutee.933
(6) Focus : l’amidon du manioc, Octobre 2006,  FAO
(8) Global Information and Early Warning System (GIEWS)
(9) Tapioca Starch Price of The Week in 2005-2011, Thai Tapioca Starch Association
(10)http://www.fao.org/ag/ags/gestion-apres-recolte/racines-et-tubercules/fr/
(11)Une nouvelle variété de manioc part à l’assaut de la faim en Afrique, Senegal Business, 30 Août 2010