FARMER'S BOOKSHELF

An information system of tropical crops in Hawaii
Department of Tropical Plant & Soil Sciences
University of Hawaii at Manoa



Cassava

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Climate


Temperature: Adaptable to the hot- lowland tropics. Prefers growth under 25-29C. Growth stops when temperature goes below 10C. Casssava is frost-sensitive.
Altitude: Sea-level to 2000 m.

Daylength: Short days promote root enlargement.


Culture


Post Planting Treatments

  1. Nutrients (fertilizers used and application quantity and methods). Under commercial conditions cassava extracts from the soil the following nutrients: 253 Kg N/Ha; 28 kg P/Ha; 250 kg K/Ha; 42 kg Ca/Ha; 29 kg Mg/Ha. Fertilizer applications should be made only as a supplement to the nutrients already found in the soil at planting time. The fertilizer should be banded at one or both sides of the rows. A 12-12-18 complete fertilizer is recommended at rates of 450-672 kg/ha.

    Soils containing less than 0.06% of exchangeable K should be supplied with 90-120 kg/Ha of K2O. Excessive N applications will promote foliage growth at the expense of root production. An urea application of 100-150 kg/Ha is recommended at post-planting time if N deficiency symptoms are observed in the foliage.

  2. Irrigation: (water requirements of the plants). Requires 150 cm of water well-distributed throughout the year.


Cultivars


Varieties

"Bitter" and "Sweet" are the two general types of cassava. The "Sweet" type is more commonly grown due to its greater yields. Colors and texture of the root peeling is often the only factor used in separating clones in the market.


Description


Name: Manihot esculenta Crantz, cassava, yuca (Spanish), mandioca (portuguese), tapioca, manioc (french).


Diseases


Bacterial blight (Xanthomonas manihotis). Control by using disease-free cuttings and by using tolerant cultivars. Also controlled by delaying planting toward end of rainy season. Also controlled with foliar applications of Pseudomonas fluorescens and P. putida strains (4 times per month) in Colombia.

Brown leaf spot (Cercospora henningsii). Use resistant or tolerant cultivars.


Weeds

Weeds are best controlled through a proper rotation scheme and with proper pre-planting cultivation to prevent germination of weeds. Pre-emergence herbicides are very effective to control weeds in cassava. Weeding is recommended at 4-5 weeks after planting and at 8 weeks after planting until crop ground-cover is complete.


Fertilizer


Type of soil

Grows well under a wide range of soils but prefers porous, friable soils with some organic matter content and depth of 30-40 cm.

Drainage requirements. Will not survive extended waterlogged conditions.

Nutritional Profile of Soil. Prefers soils with pH between 6-7, and clay content < 18% Will not tolerate saline conditions. Depending on cultivars, high yields of cassava can be obtained with pH values as low as 4.5 with 60% exchangeable Al3+ present.


Land Preparation

Land for cassava cultiation is first ploughed and then harrowed or disked. Thereafter the cassava may be planted on the flat, on ridges, or in furrows. For furrows, make them 10 cm deep, and place the cuttings horizontally in the direction of the furrow. In areas where drainage is a problem, the land is heaped in mounds or ridges, and the cassava is planted on the crest.


Handling of the Crop


  1. USDA treatments and requirements. Cassava is highly perishable and has a poor storage quality. Cassava is thus very susceptible to mechanical damage and bruising. The tubers should be cured at relatively high temperatures and relative humidities. Cure at 25 to 40C and 85 RH for suberization to occur in 1 to 4 days, and to allow for the formation of a new cork layer around the wounds about 3 to 5 days later.

    Classification: thick root, brown skin, white tissue. The root should be 150-250 mm (6-10 in) long. Pre-cooling: Pre-cool with hydrocooler or with forced air. Sensitive to bruising during handling. Transport in highway and piggyback trailers and van containers. Transport and storage life-time = 1-2 months.

  2. Packing (no. lbs/box; box type). Full telescoping fiberboard boxes, 23 kg (50 lbs.) with excelsior or paper wrapping and padding.

  3. Cleaning (methods and requirements). Post-harvest dip in 1% Clorox.

  4. Waxing (type of wax and quantity/methods). Apply an aqueous 2.2% fungicidal wax solution containing 17% triethanolamine and 5% ortho-phenyl-phenol.

  5. Vacuum packing. Not-applicable.

  6. Chemical treatments (fungicides etc.). Treat with sodium hipochlorate to reduce decomposition. Other sprays could include: thiabendazole, benomyl and aminobutane.

  7. Hot water treatments, if necessary. Not-applicable.

  8. Refrigeration requirements (after harvest and during treatment). Once harvested roots are usable for 7-10 days. With carefull handling shelf life can be increased to 1-2 weeks. Store at 0-5C (32-41F).

  9. Humidity requirements. Store at 85-90 RH.


Harvest


Expected yield per acre (based upon specific planting density). About 30 MT at a density of 10,375 plants/ha.

Timing based upon yields. 12 months after planting.


Maturity Indices (days, etc.)

Cassava can be harvested more or less whenever it is needed beginning about 7 months after harvest (MAH). Harvest at 7-16 MAP. Cultivars and climate influence maturity of cassava. The early types mature at about 6 MAP. The greatest yields are achieved at about 9-12 MAP. Prolonged maturity periods, however, turn the tubers fibrous and poor in quality.


Methods of Harvest

Plant tops are cut at 50 cm from the soil surface 1-2 weeks prior to harvest. Roots are pooled from the ground by hand.


Insects


Mites (Mononychellus tanajoa). Use tolerant cultivars and plant at the beginning of the wet season. Encourage buildup of predators.

Thrips (Frankliniella williamsi). Use resitant cultivars.

Cassava hornworm (Erinnysis ello). Parasitism by Trichogramma spp. and paper wasp (Polistes sp.)


Market/Uses


Availability

Year-round from Florida, Mexico, Central America, South America, Antillas.


Import and other World Production Data

The estimated total world production of cassava is about 120 million MT, with Africa, the Far East, and South America producing about 35%, 35% and 27% of world production, respectively.


US Costs of Production (per hectare)

According to 1978 estimates for cassava production in Southern Florida: Total production costs per hectare= $1,830.

  1. Growing Total- 38% (percent of total cost of production).

  2. Harvest Total- 61%


    Planting


    1. Planting material. Healthy stem cuttings 15-20 cm long, taken from mature mid-plant sections (10-12 seed pieces per plant). Make the cuttings just before planting.

    2. Preplanting treatment. Dip or soak stem cuttings in fungicide and when needed add minor elements to dip. A dipping formula can include (per liter of water): Dithane M-22 (maneb) 2.2 g; Antracol (propineb) 1.2 g; Vitigran 35% (copper oxychloride) 2.0 g; and Malathion WP 4% (malathion) 5.0 g. The dip should also include IAA at 800 ppm to induce rooting. After being soaked for 3 min, the stakes should be allowed to dry before being stored or used for planting. This treatment will protect the cuttings from attack by soil-born pathogens and by surface pests such as mites and mealybugs.

    3. Depth of Planting. Plant the stems cuttings (1 per hole) in a horizontal position to a depth of 5-10 cm. Stem cuttings are carried by a wagon (usually pulled by a tractor) and placed in the rows. The cuttings are properly placed and covered afterwards.

    4. Timing of planting (crop cycle). Planted at any time of the year when supplemental irrigation is available.

    5. Planting density (expected germination). Plant cuttings at a spacing of 1.2 x 0.8 m (10,375 plants/ Ha). The exact spacing depends on the cultivar utilized. If the cuttings have been planted in moist soil under favourable conditions, they produce sprouts and adventitious roots within a week. Expected germination is 100% with healthy planting material.