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| ## cassava {#cassava .Title-Header}                                   |
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| *Manihot esculenta* Crantz                                            |
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| Plant Symbol = MAES                                                   |
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Contributed by: USDA NRCS National Plant Data Center, Baton Rouge,
Louisiana and Pacific Islands West Area Office, Mongmong, Guam

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height="3.7402777777777776in"}

##### Alternate Names {#alternate-names .Header-3}

Cassada, manioc, yuca, tapioca, mandioca, shushu, muk shue, cassave,
maniok, tapioka, imanoka, tapioca, maniba, kasaba, katela boodin,
manioc, manihot, yucca, mandioca, sweet potato tree, Brazilian
arrowroot, and tapioca plant.

**Caution**: The root of the bitter variety is very poisonous when raw.
Cooking destroys the hydrocyanic acid; the cooking water must be
discarded.

##### Uses {#uses .Header-3}

*Food products:* There are hydrocyanic glucosides (HCN) in all parts of
the plant that are poisonous. These glucosides are removed by peeling
the roots and boiling in water.

Cassava is one of the leading food and feed plants of the world. It
ranks fourth among staple crops, with a global production of about 160
million tons per year. Most of this is grown in three regions: West
Africa and the adjoining Congo basin, tropical South America and south
and Southeast Asia. The young tender leaves are used as a potherb,
containing high levels of protein and vitamins C and A. The leaves are
prepared in a similar manner as spinach, while eliminating toxic
compounds during the cooking process.

It is mainly used for human consumption, less for animal consumption and
for industrial purposes, though this may vary by country. The roots are
rarely eaten fresh but are usually cooked, steamed, fried or roasted
when fresh or after drying or fermenting. It is advisable to peel, boil,
grind or cut, and dry the roots in order to diminish the contents of
cyanogenic glucosides. All plant parts contain cyanogenic glucosides
with the leaves having the highest concentrations. In the roots, the
peel has a higher concentration than the interior. In the past, cassava
was categorized as either sweet or bitter, signifying the absence or
presence of toxic levels of cyanogenic glucosides. Sweet cultivars can
produce as little as 20 mg of HCN per kg of fresh roots, while bitter
ones may produce more than 50 times as much. The bitterness is
identified through taste and smell. This is not a totally valid system,
since sweetness is not absolutely correlated with HCN producing ability.
In cases of human malnutrition, where the diet lacks protein and iodine,
under processed roots of high HCN cultivars may result in serious health
problems.

Cassava provides a major source of calories for poor families, because
of its high starch content. With minimum maintenance, the farmers can
dig up the starchy root of the cassava and eat it 6 months to 3 years
after planting. In Africa, people also eat the leaves of the cassava as
a green vegetable, which provide a cheap and rich source of protein and
vitamins A and B. In Southeast Asia and Latin America, cassava has also
taken on an economic role. Various industries use it as a binding agent,
because it is an inexpensive source of starch.

Cassava flour is used to make cookies, quick breads, loaf breads,
pancakes, doughnuts, dumplings, muffins, bagels.  Cassava extracted
juice is fermented into a strong liquor called kasiri. The peeled roots
of the sweet variety are usually eaten cooked or baked.

The juice can be concentrated and sweetened until it becomes a dark
viscous syrup called kasripo (casareep). This syrup has antiseptic
properties and is used for flavoring.

*Livestock*: Cassava leaves and stem meal are used for feeding dairy
cattle. Both fresh and dried cassava roots are consumed by ruminants in
different forms (chopped, sliced, or ground). Cassava bushes three to
four months old are harvested as forage for cattle and other ruminants.

*Ornamental*: One clone with variegated leaves is known to be planted as
an ornamental.

*Commercial*: Cassava starch is used in the production of paper,
textiles, and as monosodium glutamate (MSG), an important flavoring
agent in Asian cooking. In Africa, cassava is used as partial
substitution for wheat flour.

*Ethnobotanic*: In Samoa, cassava was used to induce abortion. The
Amerindians use the brown juice, obtained during processing, for burns.

##### Status {#status .Header-3}

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status (e.g. threatened or endangered
species, state noxious status, and wetland indicator values).

#####  {#section .Header-3}

##### Description {#description .Header-3}

Milkweed Family (Euphorbiaceae). Cassava is a tall semi-woody perennial
shrub or tree, up to 7 m high, dbh up to 20 cm, single to few stems,
sparingly branching; branchlets light green to tinged reddish, nodes
reddish. The outer bark is smooth, light brown to yellowish grey; inner
bark cream-green; exudate thin, watery; wood soft, creamy straw. The
leaves: petiole light greenish to red; blade basally attached or
slightly (up to 2 mm) peltate, dark green above, pale light greenish
grayish underneath, sometimes variegated; lobes narrow, 2.9-12.5 times
as long as wide; central unlobed part usually short, lobes 15-21 times
as long. Inflorescences lax, with 3-5 together in fascicles; pedicels
light green to red. Staminate flowers: calyx divided to halfway or more,
green to white to lobes white to reddish with white median band inside
to red purple, glabrous except for apex of calyx tube and inner side of
segments finely hairy; filaments white, anthers yellow; disc yellow to
light orange. Pistillate flowers: calyx green with red margin and
midrib, hairy along the margin and on the midrib inside; disc pink;
ovary with 6 longitudinal ridges, green (with pinkish stripes) to
orange; pistil and stigmas white. *Fruit* subglobose, green (to light
yellow, white, dark brown), rather smooth, with 6 longitudinal wings.
*Seeds* up to 12 mm long.

The tuberous edible root, grows in clusters of 4-8 at the stem base.
Roots are from 1-4 inches in diameter and 8-15 inches long, although
roots up to 3 feet long have been found. The pure white interior is
firmer than potatoes and contains high starch content. The roots are
covered with a thin reddish brown fibrous bark that is removed by
scraping and peeling. The bark is reported to contain toxic hydrocyanic
(prussic) acid, which must be removed by washing, scraping and heating

In general, the crop requires a warm humid climate. Temperature is
important, as all growth stops at about 10ºC. Typically, the crop is
grown in areas that are frost free the year round. The highest root
production can be expected in the tropical lowlands, below 150 m
altitude, where temperatures average 25-27°C, but some varieties grow at
altitudes of up to 1 500 m.

The plant produces best when rainfall is fairly abundant, but it can be
grown where annual rainfall is as low as 500 mm or where it is as high
as 5,000 mm. The plant can stand prolonged periods of drought in which
most other food crops would perish. This makes it valuable in regions
where annual rainfall is low or where seasonal distribution is
irregular. In tropical climates the dry season has about the same effect
on Cassava as low temperature has on deciduous perennials in other parts
of the world. The period of dormancy lasts two to three months and
growth resumes when the rains begin again.

Cassava is drought resistant and grows well in poor soil. It is one of
the most efficient producers of carbohydrates and energy among all the
food crops.

*Distribution*: Cassava can be found from the United States to Africa,
Asia, Europe, and the South Pacific. For current distribution, please
consult the Plant profile page for this species on the PLANTS Web site.

##### Establishment {#establishment .Header-3}

Cassava is a tropical root crop, requiring at least 8 months of warm
weather to produce a crop. However, under adverse conditions such as
cool or dry weather it can take 18 or more months to produce a crop.
Cassava is traditionally grown in a savanna climate, but can be grown in
extremes of rainfall; however, it does not tolerate flooding. In
droughty areas it looses its leaves to conserve moisture, producing new
leaves when rains resume. Cassava does not tolerate freezing conditions,
but does tolerate a wide range of soil pH 4.0 to 8.0 and is most
productive in full sun.

*Propagation by seed*: For agricultural purposes, cassava is propagated
exclusively from cuttings because seed germination is usually less than
50 percent. Seedlings are raised from seed only for the purpose of
selecting seedlings with fewer and smaller roots than those of the
parents. Botanically seeds are used only for breeding purposes.

*Propagation by cuttings*: Propagate cassava by planting segments of the
stem. Cut stems into 9-30 cm lengths; be sure to include at least one
node. Segments can be buried vertically with 8-15 cm in the ground. The
selection of healthy, pest-free cuttings is essential. Stem cuttings are
sometimes referred to as \'stakes\'. In areas where freezing
temperatures are possible, plant cuttings as soon as the danger of frost
has past. Cuttings can be planted by hand or by planting machines. Hand
planting is done in one of three ways: vertical, flat below the soil
surface or tilted. Under low rainfall conditions, vertical planting may
result in the desiccation of the cuttings, while in areas of higher
rainfall; flat-planted cuttings may rot. In general, flat planting 5-10
cm below the soil surface is recommended in dry climates and when
mechanical planting is used. Germination seems to be higher; tubers tend
to originate from a great number of points and grow closer to the
surface of the soil, making better use of fertilizers applied on the
surface and also making harvesting easier.

Vertical planting is used in rainy areas and tilted planting in
semi-rainy areas. Observing the polarity of the cutting is essential in
successful establishment of the planting. The top of the cutting must be
placed upright. Typical plant spacing is 1m by 1m. Cuttings produce
roots within a few days and new shoots soon appear at old leaf petiole
axes on the stem. Early growth is relatively slow, thus weeds must be
controlled during the first few months. Although cassava can produce a
crop with minimal inputs, optimal yields are recorded from fields with
average soil fertility levels for food crop production and regular
moisture availability.

Responses to macro-nutrients vary, with cassava responding most to P and
K fertilization. *Vesicular-arbuscular* mycorrhizae benefit cassava by
scavenging for phosphorus and supplying it to the roots. High N
fertilization, more than 100 kg of actual N/ha, may result in excessive
foliage production at the expense of storage root development.
Fertilizer should only be applied during the first few months of growth.

In moist soil, sprouting takes place within the first week after
planting. Within a month of the beginning of planting, the substitution
of new cuttings to replace those that did not sprout is still possible.
Cassava is grown mainly as a cash crop and farmers may for ten years or
more grow cassava on the same land. However, if the price of cassava
roots drops, the farmers may shift to another crop (e.g., sugarcane,
maize or sorghum) until cassava again becomes the more profitable crop.

##### Management {#management .Header-3}

*General*: Cassava is either planted as a single crop or intercropped
with maize, legumes, vegetables, rubber, oil palm or other economic
important plants. Mixed planting reduces the danger of loss caused by
unfavorable weather and pests by spreading the risk over plants with
different susceptibilities.

Cassava grows best on light sandy loams or on loamy sands which are
moist, fertile and deep. It grows well on soils ranging in texture from
the sands to the clays and on soils of relatively low fertility. Cassava
can produce an economic crop on soils so depleted by repeated
cultivation that they have become unsuitable for other crops. On very
rich soils the plant may produce stems and leaves at the expense of
roots. Cassava will grow on a wide range of soils, provided the soil
texture is friable enough to allow the development of the tubers.

When cassava is grown as the first crop in forest land no further
preparation is required than the clearing of the forest growth. When
cassava is grown after other crops it often can be planted without
further preparation of the soil, once the preceding crop has been
harvested or the soil has been plowed two or three times until free from
grass and other plants.

No fertilization is required when the land is freshly cleared or when
there is enough land to enable growers to substitute new land for old
when yields fall. Like all rapidly growing plants yielding
carbohydrates, cassava has high nutrient requirements and exhausts the
soil very rapidly. When cassava is grown on the land for a number of
years in succession or in rotation the soil nutrients are reduced and
must therefore be returned to the soil by fertilization. Large
commercial farmers replace the nutrients lost by applying artificial
fertilizers that are usually too costly for the small farmer. Small
farmers replace the nutrient loss by using different kinds of organic
manures, such as cattle or duck manure or garbage to replace the
nutrients taken from the soil.

Cassava is frequently cultivated as a temporary shade plant in young
plantations of cocoa, coffee, rubber or oil palm. When cultivated as a
temporary shade plant, no special attention is given to the cassava
plant. When grown alone, the plants require little maintenance after
planting. Irrigation may be required if there is no rain, and hoeing of
the earth helps preserve the subsoil humidity, especially in dry sandy
soils. The chief problem is weed control which may be desirable to weed
the crop two or three times until the plants are well developed and
their shade prevents the growth of weeds.

Maturity differs from one variety to another, but for food the tubers
can be harvested at almost any age below 12 months. From the standpoint
of maximum starch production, the optimum age for harvest is 18-20
months. During this growth period both root and starch production
increase rapidly to their maximum value, after which root production
decreases slowly and starch production much more rapidly on account of
the declining starch content of the tubers.

If the roots are left in the ground, starch content increases with age
until, at a certain point; lignifications takes place, causing the roots
to become tough and woody, so that they are harder to prepare for
consumption and other uses.

Harvesting of cassava can be done throughout the year when the roots
reach maturity. In regions with seasonal rains, harvesting is usually
done in the dry season, during the dormant period of the plant; where
rain prevails all year round, cassava is harvested throughout the year.

There is no mature stage for cassava; because plants are ready for
harvest as soon as there are storage roots large enough to meet the
requirements of the consumer. Under the most favorable conditions,
yields of fresh roots can reach 90 t/ha while average world yields from
mostly subsistence agricultural systems average 10 t/ha. Typically
harvesting can begin as soon as eight months after planting. In the
tropics, plants can remain un-harvested for more than one growing
season, allowing the storage roots to enlarge further. However, as the
roots age and enlarge, the central portion becomes woody and inedible.

Harvesting is still generally a manual operation, although equipment to
facilitate this operation is being considered. The day before harvest,
the plants are \"topped\" the stalks are cut off 40-60 cm above ground
by hand, machete or machine and piled at the side of the field. This
length of stalk is left as a handle for pulling. Material required for
the next planting is selected and the rest is burned. In light soils the
roots are slowly drawn from the soil simply by pulling the stems or with
the help of a kind of crowbar and the tubers are cut off the stock. In
heavier soils a hoe may be required to dig up the roots before the plant
is pulled out. It must be noted that once the plants have been topped,
lifting of the roots must not be delayed, as sprouting and a drastic
fall in the starch content of the tubers will result.

Once the roots are harvested, they begin to deteriorate within about 48
hours, initially owing to enzymatic changes in the roots and then to rot
and decay. The roots may be kept refrigerated for up to a week or stored
in the ground for longer periods if they are not detached from the
plant.

**Mechanization**

In most of the tropical world cassava is grown on small plots; however,
in some countries (e.g., Mexico, Brazil, and Nigeria) large plantations
have been established. The degree of mechanization depends on the amount
of land, available labor in the area and general policy regarding the
use of manual labor.

The use of machinery for land preparation is preferable to manual labor
to ensure the best possible seed bed for tuber development. Subsequent
operations of planting, weeding, topping and harvesting can be done by
hand as well as by machinery.

The following is an outline of the present use of machinery in cassava
cultivation:

-   The hoe remains the principal implement for cultivating, weeding and
    harvesting.

-   Plowing and harrowing, are usually done by tractor.

-   A mechanical two row planter using a tractor driver and two men on
    the machine to feed cuttings from the reserve bins into the rotating
    planting turntable. In operation, the cuttings fall in succession
    through a hole into a furrow opened by a simple furrower. A pair of
    disks throws dirt into the furrow and floats pulled by chains pack
    the soil over the cuttings. The planter is able to cover about 5
    hectares per day.

-   A gasoline-powered table saw is used to prepare the cuttings for
    planting. The machine has the advantage of speed and regularity of
    produced cuttings.

-   A topping machine consisting of a heavy screen mounted on the front
    of a tractor has been developed to push down the tops: then a rotary
    mower on the back of the same tractor can cut the downed top to make
    harvesting by hand possible. The height at which the tops are cut
    back can be easily regulated with any rotary mower.

-   Cassava is not a crop that lends itself readily to mechanical
    harvesting because of the way the tubers grow. They may spread over
    1 m and penetrate 50 60 cm. Careless use of machinery for harvesting
    can damage tubers, resulting in a darkening due to oxidation that
    will lower the value of the flour. The mould-board plow has been
    used to make hand harvesting less tedious. Stalks can be cut
    successfully by a mid-mounted mower or a topping machine, and the
    roots are lifted mechanically with a mid-mounted disk terrace.

##### Pests and Potential Problems {#pests-and-potential-problems .Header-3}

Insects, diseases and other pest: In many regions, the cassava plant is
not normally affected by diseases or pests. However, in others it may be
attacked by the following:

-   Virus diseases. Mosaic, the brown streak and leaf curl of tobacco
    may attack leaves, stems and branches. Many parts of Africa harbor
    these diseases and attempts are being made to select resistant
    varieties.

-   Bacterial disease. Bacteria such as Phytomonas manihotis (in
    Brazil), Bacterium cassava (in Africa) and Bacterium solanacearum
    (in Indonesia) may attack roots, stems or leaves of cassava plants.

-   Mycoses. There are kinds which attack roots, stems, or leaves of
    cassava plants and cause various diseases.

-   Insects. Some insects affect the plant directly (locusts, beetles
    and ants); others affect the plant indirectly by the transfer of
    virus (aphids).

-   Animals. Rats, goats and wild pigs are probably the most
    troublesome; they feed on the roots, especially in areas adjacent to
    forests

##### Cultivars, Improved, and Selected Materials (and area of origin) {#cultivars-improved-and-selected-materials-and-area-of-origin .Header-3}

Contact your local Natural Resources Conservation Service (formerly Soil
Conservation Service) office for more information. Look in the phone
book under "United States Government." The Natural Resources
Conservation Service will be listed under the subheading "Department of
Agriculture."

##### References {#references .Header-3}

Affran, D.K. 1968. *Cassava and its economic importance*. Ghana Farmer,
12 (4): 172-178.

Bellotti, A.C., L. Smith, and S.L. Lapointe. 1999. *Recent advances in
cassava pest management*. Ann. Review v. 44. p343-370.

Cock, J.H. 1985. *Cassava: new potential for a neglected crop*. Westview
Press, Boulder, Colorado.

Kay, D.E. 1973*. TPI Crop and Product Digest, 2. Root Crops*. Trop.
Prod. Inst., London.

Ngo Tien Dung, L. Inger and Nguyen Thi Mui 2005. *Intercropping cassava
(Manihot esculenta Crantz) with Flemingia (Flemingia macrophylla);
effect on biomass yield and soil fertility*.  Livestock Research for
Rural Development. Vol. 17, Art. #6. Accessed:
![](media/image3.png){width="0.20833333333333334in"
height="0.15625in"}January 25, 2005, from
[[http://www.cipav.org.co/lrrd/lrrd17/1/dzun17006.htm]{.underline}](http://www.cipav.org.co/lrrd/lrrd16/8/zama16060.htm)

#####  {#section-1 .Header-3}

Onwueme, I.C. 1978. *The tropical tuber crops: yams, cassava, sweet
potato, and coco yams*. Wiley, New York.

Soerianegara*s*, I. and R. H. M. J. Lemmens, 1993. *Plant* *resources of
Southeast Asia.* *Timber trees: major commercial timbers*. Pudoc
Scientific Publishers, Wageningen. Proesea, 5 (1).

University of Florida. (May) 1994*. Fact Sheet HS-575*. Horticultural
Sciences Department, Florida Cooperative Extension Service, Institute of
Food and Agricultural Sciences, Gainesville, Florida.

Welzen, P.C. van, Q.D. Nguyen & R.C.K. Chung. 1997. *A revision of the
introduced species of Manihot (Euphorbiaceae) in Malesia*. Rheedea 7:
77\--85

Zarate, J.J. 1956. *The digestibility by swine of sweet potato vines and
tubers. cassava roots and green papaya fruit*. Philippine Agriculturist,
40(2): 78

##### Prepared By {#prepared-by .Header-3}

##### *Lincoln M. Moore*, Formerly USDA, NRCS, National Plant Data Center, Baton Rouge, Louisiana

And

*John H. Lawrence*, Pacific Islands West Area Office, Pacific Islands
Area, Mongmong, Guam

##### Species Coordinator {#species-coordinator .Header-3}

*John H. Lawrence*, Pacific Islands West Area Office, Pacific Islands
Area, Mongmong, Guam

##### Edited: 09sept03 lmm; 070213jsp; 070322 jsp {#edited-09sept03-lmm-070213jsp-070322-jsp .Header-4}

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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*To file a complaint of discrimination write USDA, Director, Office of
Civil Rights, Room 326-W, Whitten Building, 14th and Independence
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*Read about [Civil Rights at the Natural Resources Conservation
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