Origin and advantages

The cassava crop (Manihot esculenta Crantz), a native to Latin America,
is mostly produced by subsistence farmers. The crop’s multiple advantages include good yields, tolerance of poor soils, drought resistance, and a capacity to be
left in the ground, thus permitting staggered harvests. Roots are harvested between 7 and 18 months, depending on variety.

Chemical composition

All the parts of the cassava plant are used for human and animal nutrition and non-food uses. Except for the aerial parts cassava products and byproducts have high starch content and are essentially energetic (124 kcal/100 g, whereas potato contains 76 kcal/100 g).   Protein levels are low, but the roots are rich in vitamin C, calcium, and potassium, with acceptable levels of the vitamin B complex.

Genetic diversity

The world’s largest collection of cassava varieties, numbering more than varieties, is held at CIAT, located near Cali, Colombia. The collection includes more than 6000 clones selected through breeding programs by CIAT and the International Institute of Agriculture Tropical (IITA), based in Nigeria.

Toxicity

The cassava plant contains two cyanogenic glucosides called linamarin and lotaustralin (known as “linked cyanide”).
They liberate the poisonous cyanide (cyanhydric acid) when the plant’s tissues break. Some varieties are known as “sweet”, with levels of less than 20 ppm of the glucosides in fresh parenchyma. In contrast, “bitter” varieties have more than 600 ppm. Levels are higher in leaves and stems than in whole roots.

Pests and diseases

Although cassava is a hardy crop, it can suffer from such diseases as bacterial blight (leaves and stems), superelongation disease (roots), root rots, and African mosaic (whole plant and caused by a virus currently found only in Africa).

Various insects attack cassava, including sap suckers (green mite, mealybug, and whitefly), leaf eaters (hornworm), stink bug, and subterranean burrower bug.

See Tables of Main Plagues
and Diseases in Cassava