T A P I O C A
Tapioca (Manihot esculenta Crantz)
Co 2, Co 3, CO (TP) 4, MVD 1, H 165, H 226, Sree Vishakam (H.1687), Sree Sahaya (H.2304), Sree Prakash (S. 856), Sree Vijaya, Sree Jaya, Sree Pekha, Sree Prabha, Co (Tp) 5, H - 97, H - 165, H - 226 and Sree Harsha are the popular varieties of cassava.
Any well drained soil preferably red lateritic loam with a pH range of 5.5 -7.0 is best suited for tapioca cultivation. It thrives best in tropical, warm humid climate with well distributed rainfall of over 100 cm per annum. This crop can be cultivated upto an elevation of 1000 m.
Planting can be taken throughout the year under irrigated condition and during April for rainfed crop.
About 17,000 setts are needed for planting one ha or 6800 setts/ acre- 75*75 spacing.
Select healthy mosaic free, vigorous plants for taking planting materials. Prepare setts of 15 cm long with 8 – 10 nodes from the middle portion of the stem. Avoid mechanical damage while preparation and handling of setts. The cut end should be uniform. Dip the setts in Carbendazim 1 g in lit of water for 15 minutes before planting. Plant the setts vertically with buds pointing upward on the sides of ridges and furrows.
For a rainfed conditions, treat the setts with a mixture of Potassium chloride @ 5 g/lit and micronutrients viz., ZnSO4 and FeSO4 each @ 0.5% for 20 minutes.
Dip the setts for 20 minutes in Azospirillum and phosphobacterium each at 30 g/lit. Setts can also be obtained from tissue culture plants grown in net houses. Theses planting materials are mosaic free.
Preparation of field
Plough the field 4 – 5 times to get a fine tilth. The soil depth should be atleast 30 cm and form ridges and furrows at the following spacing.
Plant the setts vertically with buds pointing upward on the sides of ridges and furrows at following spacings.
Irrigated: 75 x 75 cm (17,777 setts) and 90 x 90 cm (12,345 setts)
Rainfed: 60 x 60 cm (27,777 setts)
Under Kanyakumari conditions: 90 x 90 cm (12,345 setts)
First irrigation is given at the time of planting. Life irrigation is given on the 3rd day followed by once in 7 – 10 days upto 3rd month and once in 20 – 30 days upto 8th month.
Each rooted cutting has to be given pot-watering at the time of planting if there is no adequate rain moisture in the soil. Later on, if dry spell prevails, irrigate the crop at 15-20 days interval in chalka soils.
Raise Co 2 vegetable cowpea during March and harvest green pods before planting cassava during June –July. After green pod harvest, incorporate the cowpea haulms into the field by disc ploughing. Through sequential cropping 50% reduction in application of FYM (12.5 t/ha) and P (30 kg/ha) is ensured.
Apply 25 t/ha FYM and incorporate at the time of ploughing. Apply 45:90:120 kg NPK/ha as basal and 45:120 kg NK/ha on 90 days after planting during earthing up.
FYM at 12.5 t/ha along with 50 kg N, 65 kg P and 125 kg K/ha is applied as basal. 2 kg of Azatobactor is applied as soil application at 30 – 60 days after planting on receipt of showers (2.0 kg Azatobacter + 20 kg FYM + 20 kg soil per hectare).
Micro nutrient deficiency can be controlled by foliar spraying of 1% FeSO4 + 0.5% ZnSO4 at 60 and 90 DAP.
Fill up the gaps within 20 days of planting. Carry out 1st weeding 20 days after planting. Subsequent weedings should be done once in a month upto 5 months depending upon the weed intensity.
Thin to two shoots per plant during 60th day. Grow aggregatum onion, coriander, short duration pulses and short duration vegetables as intercrops.
Crop can be harvested at 9 to 11 months after planting. During tuber maturity, the leaves become yellow and 50 % of leaves become dried and sheds off. The soil near the stem base of the stem shows cracking. Tubers can be uprooted by using fork or crow bar.
Irrigated : 40 - 50 t/ha
Rainfed : 20 - 25 t/ha
Post -Harvest technology for planting materials
The planting material is to be stored as whole stem under the shade of trees with stems in verticle position for next planting season. They should be treated with fungicide like Dithane M-45 (40 g/10L) to prevent diseases and insecticide like Karathane 0.05% (10 ml/o lt) or Malathion(20 ml/10 Lit) to prevent mites and other insects.
Mites can be controlled by spraying with Dicofol 18.5 EC 2.5 ml/lit during 3rd and 5th month.
White fly (Bemisia tabaci)
Integrated pest management practices:
Select the planting materials from healthy plants. For the control of white fly vectors, adopt IPM practices mentioned above.
Cercospora Leaf spot
Cercospora leaf spot can be controlled spraying Mancozeb at 2 g/lit twice at 15 days interval.
Avoid water stagnation. Give good drainage facilities. Spot drenching with Copper oxychloride 2.5 g/lit.
Spray 3 to 4 times Ferrous sulphate 2.5 g/lit on the appearance of deficiency symptom at weekly intervals. Equal quantity of lime should be added for neutralising the solution.