[CASSAVA] (Manihot esculenta)
Tapioca belongs to the family Euphorbiaceae.Tapioca grows
and produces best under warm humid tropical conditions
where rainfall is well distributed and fairly abundant.
It can also be grown under irrigation where rainfall is
low. Its outstanding characteristic in terms of moisture
requirements is the ability to withstand fairly prolonged
periods of drought. However, at the time of planting there
must be sufficient moisture for the plant to establish
itself. The crop cannot withstand cold and is killed by
The crop grows well in well-drained laterite, gravelly
and sandy loam soils. Heavy and rocky soils are less
suitable because they restrict root development. The
crop cannot survive waterlogged conditions and in such
areas, it must be planted on mounds or ridges that permit
drainage. The crop can also be gown on hill slopes and
on wastelands of low fertility.
H-97: This is a semi-branching variety, tolerant to
mosaic disease with duration of 10 months. But the
harvest can be prolonged even up to 16 months. The
starch content is 30%.
H-165: This is a non-branching type with poor cooking
quality having eight months duration. It is tolerant
to mosaic but susceptible to wilt disease. The starch
content is 24.5%.
H-226: This is a semi-branching type with medium cooking
quality having 10 months duration. It is moderately
susceptible to mosaic. The starch content is 29%.
M-4: This is an erect type with excellent cooking
quality having 10 months duration. The starch content
Sree Visakham: This is a semi-branching type with
yellow coloured flesh having 10 months duration. It
shows high tolerance to mosaic and low susceptibility
to pests like red mites, scale insects, thrips etc.
The starch content is 26% and vitamin A 466 IU.
Sree Sahya: This is a predominantly semi-branching
type with 10 months duration. It shows high tolerance
to mosaic and low susceptibility to pests like red
mites, scale insects, thrips etc. The starch content
Sree Prakash: This has seven months duration and the
yield potential is 30-40 t/ha.
Kalpaka: This is a non-branching type with six months
duration and is suited as an intercrop of coconut
in reclaimed alluvial soils of Kuttanad.
Sree Jaya: This is an early variety with seven months
duration and excellent cooking quality. Tuber contains
24-27% starch and is low in cyanogens.
Sree Vijaya: This is an early variety with 6-7 months
duration and excellent cooking quality. Tuber contains
27-30% starch and is low in cyanogens.
Sree Harsha: This has 10 months duration and good
cooking quality. Tuber contains 34-36% starch. They
are non-bitter and ideal for culinary purposes and
the high starch content makes it suitable for preparing
Nidhi: This is a high yielding early variety with
5.5-6 months duration. It is tolerant to mosaic and
moisture stress. Tuber contains 26.8% starch and 20
Vellayani Hraswa: High yielding early variety with
5-6 months duration. It cannot tolerate drought. The
cooking quality is very good. Tubers contain 27.8%
starch and 53 ppm cyanogen.
Sree Rekha: It is a top cross hybrid with 10 months
duration. Tubers contain 28.2% starch with excellent
Sree Prabha: It is a top cross hybrid with 10 months
duration. Tubers contain 26.8% starch with good cooking
Before planting, plough the field 2-3 times or dig to
a depth 25-30 cm depending upon soil type to establish
a deep porous field in which the setts are to be planted.
Tapioca is propagated from cuttings. Select mature healthy
stems free from diseases or pests. Discard about 10
cm from the lower mature and about 30 cm from the upper
immature end. Stems should be cut into setts of 15-20
cm length using a sharp knife. About 2000 stems are
required for planting one hectare. Harvested stems are
to be stored vertically in shaded and well-aerated places.
Spraying dimethoate (0.05%) on the stem will control
The main planting seasons are April-May with the onset
of southwest monsoon and September-October with the
onset of north-east monsoon. Planting can also be done
during February-April, provided sufficient moisture
is made available through irrigation. For maximum tuber
production, April-May planting is preferred because
the crop can effectively utilize both the monsoons.
The second best season is September-October.
Pit, flat, ridge or mound method of planting can be
adopted depending upon soil type, topography of land
and elevation so that waterlogging is avoided. Pit followed
by mound is found to be the best method of planting.
Plant the cuttings vertically after smoothening the
lower cut end, at a depth not exceeding 4-6 cm. Adopt
square method of planting at a spacing of 90 x 90 cm
@ one cutting per pit. It is preferable to adopt 75
x 75 cm spacing for non-branching varieties like M-4.
Gap filling should be done within 15 days after planting
preferably with longer setts of 40 cm length. Sree Visakha
is a choice variety recommended as an intercrop in coconut
gardens. Optimum plant population is 8000 plants per
ha with 90 x 90 cm spacing.
Sweet potato is propagated by means of vine cuttings.
To obtain vine cutting, raise nurseries from selected
tubers using the following method. Eighty kg of medium
sized weevil free tubers (each of 125-150 g) are required
for planting in the primary nursery area (100 m2 to
plant one hectare). Intercropping
Tapioca is planted at a spacing of 90 x 90 cm and it
takes about 3-3.5 months time to have enough canopy
to cover the land. So it is possible to have an intercrop
of groundnut during the early stages of tapioca crop.
Bunch varieties like TMV-2, TMV-7, TG-3, TG-14 and Spanish
improved are preferred for intercropping in tapioca.
The best season for sowing groundnut is May-June. Immediately
after planting of tapioca setts, groundnut seeds are
sown at a spacing of 30 cm between rows and 20 cm within
rows, so that two rows of groundnut can be accommodated
in between two rows of cassava. A seed rate of 40-50
kg/ha is recommended for dibbling one seed per hill.
Only well-matured and bold seeds are to be selected
for sowing. In acid laterite soils of Kerala, apply
1000 kg/ha of lime as basal dressing. A basal dose of
50:100:50 kg N:P2O5:K2O per ha should be given uniformly
to both the crops. One month after sowing of the seed,
20 kg each P2O5 and K2O and 10 kg N / ha may be given
to the intercrop along with earthing up. Once pod formation
has started (i.e., 40-45 days after sowing) the soil
should not be disturbed, as it will affect the pod development
adversely. The groundnut crop matures in 105 to 110
days. After the harvest of pods, the haulms are incorporated
in the soil along with a top dressing of 50 kg each
of N and K2O per ha for the main crop. By adopting this
practice, 20-25% additional income can be obtained.
In sandy areas intercropping tapioca with cowpea /
groundnut / black gram / green gram may be recommended
giving a spacing of 20 cm on both sides of the ridges.
The non-trailing grain cowpea variety V-26 is recommended
as a companion crop along with tapioca. For a pure crop
of tapioca or for a cropping system involving tapioca
as the main crop and the pulse crop suggested above,
the field may be irrigated once in 36 days to a depth
of 5 cm. This recommendation is for shallow water table
situations. For deep water table situations, the crop
may be irrigated once in 24 days to a depth of 5 cm.
Under conditions of well-distributed
rainfall, tapioca grows well as a rainfed crop and
irrigation is not necessary. However, the crop has
to be irrigated to provide sufficient moisture under
conditions of prolonged dry periods after planting.
When the crop is grown under irrigation, yield increase
of 150-200% over the rainfed crop has been observed.
Furrow irrigation with 25 mm water at
100 mm CPE and alternate furrow irrigation with 50
mm water at 75 mm CPE require only less water and
labour for optimum yield. Approximate irrigation interval
schedules will be 27 and 20 days respectively in summer
Cattle manure or compost may be applied at 12.5 t/ha during
the preparation of land or while filling up the pits so
as to provide about 1 kg of organic manure per plant.
Apply fertilizers N:P2O5:K2O at the rates (kg/ha) shown
H-97 and H-226: 75:75:75
H-165, Sree Visakham, Sree Sahya: 100:100:100
M-4 and local: 50:50:50
N and K2O may be applied in three split doses, i.e.,
1/3 basal, 1/3 two months after planting and 1/3 three
months after planting. Dose of P2O5 can be reduced to
half where the crop is grown for more than 3 years under
full dose of recommended fertilizers, since under such
situation there would be build up of soil P.
For August-September planted tapioca, apply half N,
full P2O5 and half K2O basally with first digging and
weeding. The remaining quantity of N and K2O may be
applied 45 days after planting at the time of intercultivation.
Note: N:P2O5:K2O at 50:50:100 kg/ha is recommended
for Sree Visakam when grown as an intercrop in coconut
garden. Higher levels of N tend to increase HCN content
of the tubers.
Keep the field free of weeds and maintain
soil loose by 2-3 shallow diggings or hoeing up to 90
days after planting followed by light earthing up. Retain
two shoots on each plant in opposite directions and
remove excess shoots about 30 days after planting.
spider mites and scale insects
Red spider mites in the field and scale insects under
storage are important pests of tapioca. Under field
conditions light infestation of mites can be controlled
effectively by spraying the crop with water at 10 days
interval from the onset of mite infestation. In the
case of very severe infestation, the crop can be protected
by spraying 0.05% dimethoate or methyl demeton at monthly
intervals from the time of appearance of mites.
The stem may be sprayed with 0.05% dimethoate before
storing as a prophylactic measure against the scales.
To control termites infesting planted setts, sprinkle
a little of carbaryl 10% or chlorpyrifos in the mounds
prior to planting.
of storage pests of cassava
Treating chips with granular salt (3%), sun drying thoroughly
and storing in gunny bags in godown are very effective
against Araecerus fasciculatus and Sitophilus oryzae.
mosaic disease (CMD)
The disease is transmitted by a white fly Bemisia sp.
As a rule, only stem cuttings from disease free plants
should be used for planting to minimize the spread of
the virus disease. For this purpose, tagging of disease
free healthy plants for selection as planting materials
must be practiced from September to December. All plants
showing even very mild symptoms must be rejected. Mosaic
tolerant varieties such as H-97 may be used to minimize
economic loss of tubers.
of disease free planting material of tapioca through
Setts of 3 to 4 node cuttings from apparently disease
free plants are collected and planted in the nursery
at a very close spacing of 4 x 4 cm so that about 500
setts can be accommodated in one square metre land.
Daily watering of the setts has to be done for the first
10 days and on alternate days afterwards. Screening
of CMD symptoms may be started 10 days after planting.
Setts showing even mild symptoms are to be removed and
burnt. This must be continued up to 20-25 days, by that
time healthy seedlings can be transplanted to the main
field. Supplementary irrigation may be given in the
transplanted field till they get established. Screening
for disease symptoms and rouging of infested plants
may be continued in field at weekly intervals up to
harvest. The selected healthy stems are again cut into
minisetts and subjected to nursery and field screening.
By adopting this technique it is possible to produce
Spray 0.2% ziram or zineb or 1% Bordeaux mixture for
control of leaf spot.
Bacterial blight is a disease noted in severe proportion
in certain parts of Kerala. Chemical control is not
effective. Use of resistant or tolerant varieties is
the only method of control. Among improved varieties,
H-97, H-226, H-1687 and H-2304 are tolerant to the disease
while H-165 is highly susceptible. Among the local varieties,
M-4, Paluvella, Pichivella, Parappilppan, Anamaravan
etc. are tolerant to the disease.
Tapioca becomes ready for harvest 9-10 months after planting.
Hybrid varieties like H-226, H-97 and H-165, when grown
under recommended management practices have recorded yields
up to 40-50 t/ha of raw tuber. The local varieties and
M-4 yield on an average 12-14 t/ha of tuber.