Introduction-
Tapioca also known as “Cassava” is cultivated mostly in East Godavari and to a lesser extent in Srikakulam, Vizianagarm and Visakhapatnam districts covering an area of 25,000 to 30,000 hectares in Andhra Pradesh. It is mostly grown as a rainfed crop in the uplands and agency areas where a number of sago and starch mills are existing. The boiled tubers are consumed as staple food largely on the West Coast. The dried leaves of Tapioca are rich in protein, serving as an excellent cattle feed. Of late the fresh leaves are being used for rearing Eri Silk warms. Dried chips and outer peel of tubers are used as an ingredient in cattle and poultry feeds. The fresh tubers and leaves contain harmful ‘Hydrocynic acid’(HCN) and hence are to be either sun dried for 5-7 days or boiled for 15 minutes for human consumption or cattle purpose.
Scientific name- Manihot esculenta.
Climate requirement for Tapioca-
Tapioca is a tropical crop requiring warm humid climate. It requires well distributed annual rainfall when grown under rainfed conditions. It is known for its drought tolerance and hence being grown as rainfed crop successfully.
Season required for Tapioca-
June-July
Soil requirement-
Light soils viz., sandy loam or red loam of laterite with pH between 4.5 to 6.6 best suited. Soils of low fertility status can also be used.
Tapioca Varieties-
1.H-226
Semi-branching hybrid and bears medium sized tubers with light brown skin having purplish patches. The flesh is white. It possesses good quality tubers. It can be harvested 7-8 months and contains 29% starch, suitable for industries. Average yield ranges between 25-30 t/ha.
2. H-165
Non-branching and bears short, conical tubers with golden brown skin. It can be harvested after seven months. Contain 23-24% starch. Average yield 25-30 t/ha.
3. Sree Sahya
Semi branching and the tubers are light brown, white fleshed, encased in a creamish rind. The starch content is 30.0% with a yield potential of 30 t/ha. Well suited for human consumption and for sago industry.
4. Sree Prabha
Semi spreading and the tubers are light brown, white fleshed, encased in a creamish rind. The starch content is 29.0% with a yield potential of 35-40 t/ha. Suitable for both upland and lowland conditions.
5. Sree Prakash
Sparsely branching, short duration (7 months) selection. The tubes are brown, stout and medium-sized having white flesh, yield ranges between 20-25 t/ha. The starch content is 20.0%
6. Sree Jaya
Sparsely branching, short duration (7 months) selection. The tubes are brown, stout and medium-sized having white flesh, yield ranges between 26-30 t/ha.
7. M4
Nonbranching table variety. It can be harvested in 8-10 months. The tubes are brown, linear and medium-sized having white flesh, yield ranges between 18- 23 t/ha.
Propagation of Tapioca-
Tapioca is propagated through stem cuttings taken from mature healthy and disease free plants. Around 6-8 cuttings of 20 cm can be obtained from a mature stem, rejecting the tender growth at the top and thick woody portion at the base.
Preparatory Cultivation-
The land should be ploughed 4-5 times to a depth of 30-35 cm. Apply FYM 12.5 t/ha, in the last ploughig along with 375 kg Superphosphate (60kg P2O5 ) and 50kg Lindane dust (to control termites) and incorporate in the soil by ploughing. Prepare the land into flat beds with good drainage channels.
Planting of Rooted Cuttings-
The mature stems should be made into 20 cm cuttings using any sharp implement (country knife or Kattipeetha) without damaging the buds. The cuttings are to be immersed in a solution of Dithane M-45 (3 gram) + Dimethoate 2 ml/lit of water for 5 minutes and then planted in a raised nursery bed, side by side for 7-10 days with daily watering to allow them to initiate rooting.The rooted cuttings are to be planted in the main field at 90 x 90 cms to a depth of 5cm inside the soil. There should be optimum moisture at the time of planting. There should be 12,345 plants per ha. For which about 13,000 rooted cuttings are to be maintained including those for gap filling.
Manures and Fertilizers for Tapioca-
A fertilizer dose of 60:60:60 kg of NPK/ha has to be applied along with FYM 12.5 t/ha. Whole P2O5 is to be applied as a basal dose in the last ploughing. N and K2O are to be applied in three equal split doses at 30, 60 and 90 days after planting. They are to be applied around the plant by making a ring at 10-15cm distance from the plant and cover with soil.
Intercultivation-
It is an important operation in Tapioca cultivation. Light digging or hoeing should be given at least thrice during early stages to remove weeds. Two healthy shoots per plant have to be retained on opposite side by removing the rest.
Irrigation of Tapioca-
Each rooted cutting has to be given pot-watering at the time of planting if there is no adequate rain or moisture in the soil. Later on, if dry spell prevails, irrigate the crop at 15-20 days interval in chalka soils.
Best crop suited for intercropping with Tapioca-
Intercrops like Greengram, Blackgram, Groundnut and Maize can be grown to derive an additional income of about Rs. 1500/- per ha. within 2 ½-3 months. The intercrops have to be sown along with planting of Tapioca and fertilized separately as per their fertilizer requirement. They are to be harvested before 90 days.
The practice of growing intercrops is seldom followed in Tapioca in East Godavari District of Andhra Pradesh as it comes in the way of frequent operations of local ‘gorru’ in between the rows by the farmers for checking weed growth and to make the soil prous for better growth and development of tubers.
Harvesting of Tapioca-
Tapioca becomes ready for harvest by 7-8 months after planting in East Godavari District. Harvesting is done by digging with crowbars. The fresh tubers are highly perishable and can be stored only for 2-3 days.
Tubers may be cut into chips and sun dried for a week and stored with 12-13% of moisture content for 2-3 months in air tight containers.
Post harvest Technology-
The palnting material is to be stored as whole stem under the shade of trees with stems in vertical position for next planting season. They should be treated with fungicide like Dithane M-45 (3 g) /) + Malathion (2 ml) or Chloripyriphos (2 ml) per litre of water to prevent the incidence of diseases and pests during storage.The planting material can also be stored safely in “ Zero energy cool chanber method”.
Plant Protection
Pests of Tapioca with its control-
1. Scale insect(Aonidomytilus albus)
White scale colonics appear on stems. Drying of stems takes place under storage. Stem becomes weak and dry, causing side branching to give bushy appearance. Viability of planting material is reduced, resulting in the poor establishment.
Control
Scale-free stems should be collected for storing and planting. Staking stems in horizontal position encourages multiplication of scales due to the development of higher temperature and humidity. Therefore healthy stems are to be kept in a vertical position under shade to facilitate easy aeration and diffused dry light. As a prophylactic measure, the stems may be sprayed with Dimethoate 0.05% at the time of storing. If infestation is observed, one more spraying may be done. The infested stems should be rejected and burnt at the time of planting. In case of acute shortage of planting material and the scale attack is mild, sets can be given a dip in the above insecticidal solution for 10-15 minutes before planting.
2. Spider mites (Tetranychus cinnabarinus, T.neocaledonicus)
This group of spidermites colonizes on lower surface, causes elongated yellowish streaks, chlorosis, withering and drying of leaves. Depletion of chlorophyll content of leaves affecting photosynthetic efficiency and yield.
Control
Spray Dimethoate or Methyl demeton 0.05% in severe infestation January-April. Spraying water at run off level is effective. This has an added advantage of preserving the biotic agents of mites. Foliar application of urea followed by spraying of Dimethoate 0.05% in the severe case to contain the pest outbreak is recommended as an IPM approach.
Diseases of Tapioca with its control-
1. Cassava mosaic disease (Indian cassava mosaic geminivirus)
The important disease of Tapioca is ‘Cassava mosaic’ in Andhra Pradesh. Only stem cuttings from mosaic free plants should be used for planting to minimize the spread. The mosaic disease is transmitted by a vector called white fly (Bemesia tabaci).
Chlorotic areas intermixing with normal green tissue gives mosaic pattern. In severe cases leaves are reduced in size, twisted and distorted, reducing chlorophyll content and photosynthetic areas. It causes 25-80% yield reduction.
Control
Use disease-free planting material. Grow field tolerant varieties H165 and Sree Sahya. Rogue out infected plants and follow strict field sanitation.
Spraying 0.03% Dimethoate 3-4 times at monthly intervals for the first four months of the crop, controls the vector and thereby the spread of the disease.
Source –
- Dr. Y. S. R. Horticulture Univertity, Andhra Pradesh.
