Food security

Cassava: A plant for all times

If you look across a field in Nigeria, you might see hundreds of midsize trees with green leaves and strange roots being dug up. This tree-looking plant is called cassava. Cassava is the third most important source of calories in the world, behind rice and corn. As many as 800 million people use it as a food source. It may surprise you to find out that most Americans have likely consumed cassava in the form of tapioca! Tapioca is used as a common thickening agent and pudding filler. It’s also what is found in the popular “boba tea.”

person tending to cassava plant consisting of tree-like branches, leaves, and tubers under soil
Cassava is a perennial, tree-like plant, which can be harvested all at once, or by cutting off roots as needed. Credit: S Mallowa

Cassava is a root crop that is high in starch. It is predominantly found in tropical or heated climates. Its growth cycle varies from eight to 23 months, depending on variety. It’s also a perennial crop.

The cassava crop can be harvested at once for processing. Or, if grown by smallholder farmers (less than 5 acres), they may harvest by taking only a few roots at a time over the course of up to a year, depending on need. Cassava roots attached to the plant stay fresh and heathy. Cassava grows in areas of sandy soil and spots of low fertility.

pile of cassava cuttings that are four to ten inches long
Cassava can be harvested as a group or piecemeal. The latter allows smallholder farmers to cut and use as needed. Shown: Cassava cuttings 4 – 10 inches long in Southeast Asia. Credit: J. Legg

Adding in its long growth and harvest cycle, it is a key food security crop in war torn countries. It is a crop of choice to fight poverty in Africa. This makes the crop popular in countries that cannot produce rice or wheat. The Congo Basin, Latin America, and Southeast Asia are all geographic areas in which the crop is grown. The crop is native to South America; however, Nigeria, Thailand, and Indonesia are currently the top three cassava producing countries. 

Cassava is grown for consumption as both animal feed and human food. There are versions that are high in cyanide and therefore tend to be bitter and need a measure of processing before consumption like pounding or drying and milling.

tied cassava cuttings with leaves sprouting above them
Cassava cuttings with leaves sprouting in Brazil. Cassava is a perennial that grows in a tree-like habit. Depending on the variety, it matures between 8 to 23 months. Credit: J Legg

There is a wide variety of products made from cassava include baking flour, juice, and syrup. You can find cassava products at your local grocery store or even entire cassava roots or cassava leaves at a supermarket specializing in international products. Cassava is also used in some laundry starches to keep clothes from wrinkling. 

Cassava is the primary source of food for many parts of the world. However, since the plant is mostly starch, those who depend on the plant for their entire diet are prone to nutritional deficiencies. There is also a danger of cyanide poisoning when the plants are not properly prepared or when high cyanide varieties are consumed in large quantities. This is a rare occurrence. 

dozens of very long cassava cuttings tied and ready for transport or storage
Cassava cuttings ready for transport or storage. Credit: J. Legg

Pests and diseases affect all living organisms, cassava is no exception. Two viral diseases, cassava mosaic disease and cassava brown stem disease are a huge production constraint in Africa and Asia. These diseases decrease the yield of the cassava plants and wreak havoc on communities that depend on the crop. Outbreaks of the disease have been recorded worldwide but the hardest hit areas have been in the Congo Basin. Development of resistant varieties of cassava could help in increasing resistance to better manage these diseases. Research is ongoing to find varieties that can better withstand the disease that affect the production of cassava. 

Answered by Augustana University’s Global Food Security and Plant Pathology Students supervised by Sally Mallowa: Austin Lannen, Brenden Bergquist, and Sarah Rath  

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

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