FARMER'S BOOKSHELF

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


Dasheen

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Climate

Temperature: Prefers warm conditions. Does not withstand freezing. Optimum temperature for growth is 24C, range 13-30C.

Altitude: From sea-level to 1500 m in the tropics.

Culture

Post Planting Treatments

  1. Nutrients (fertilizers used and application quantity and methods). Fertilizer applications should supplement the nutrient levels already found in the soil at planting time. Apply a 10-20-20 fertilizer in 3 separate applications of 500 kg/ha each. . The applications are made at 2, 5 and 7 months after planting. The initial fertilizer application should include 1.5% Mg, 1% Mn, and 0.1% Zn. The application of chelated iron (sequestrene 330 and 138), drenched on the soil at the rate of 20 lbs in 30 00 gallons of water broadcasted per acre (40 kg Fe in 25,000 liters of water per Ha), is applied if Fe deficiencies are observed. Add Ca at planting at the rate of 25 kg/Ha.

  2. Irrigation: (water requirements of the plants). Optimum rainfall is 140-200 cm for the growing season. Irrigate at least 3 cm (1 inch) per week. Irrigation is usually with an overhead pump mounted on a truck bed or trailer that irrigates 1 ha pe r hr.

Cultivars

Varieties:

  1. Xanthosoma caracu, cultivars Roliza and Yautia blanca. Grown in the Caribbean region. Cormels are white fleshed and non-acrid.

  2. X. sagittifolium. White fleshed.

  3. X. atrovirens. Grown in Caribbean region. Gray-green leaves with powdery bloom, yellow-orange cormels and corms.

Description

Name: Xanthosoma sagittifolium (L.) Schott, cocoyam, tannia, malanga, yautia.

Diseases

Root rot- `mal seco' or `leaf-burning disease' is the most serious disease in Africa and the Caribbean, believed to be caused by a complex of pathogens involving Pythium myriotylum. Root rots also caused Corticum rolfsii. Controlled with a prompt harvest, by avoiding infected fields, and by using clean seed stock. Corm and root rots can be avoided by planting in well-drained soils.

Tannia (dynastid beetle, Ligrus ebenus). Control with malathion.

Dasheen mosaic virus. Use virus-free seed stock.

Weeds should be controlled for the first 3 months after planting. Soil is moved up around the plant to control weeds and to enhance underground storage organ size. Weed at least 3 times per season. Herbicides are not registered for use on cocoyam in Florida, thus, weeding is done by cultivation with tractors and by hand.

Fertilizers

  1. Type of soil. Soil with good aeration and with good moisture holding capacity.

  2. Drainage requirements. Can tolerate high rainfall areas, provided there is good drainage.

  3. Nutritional Profile of Soil. Prefers a pH range of 5.5-7.8. Depending on cultivars, high yields can be obtained with pH as low as 4.8 and 20% exchangeable Al3+.

  4. Land Preparation. Cultural methods for land clearing include shredding or cutting and chopping weeds before planting. After the land is cleared, the field is plowed, followed by harrowing or rotovation at 5-7 day intervals.

Harvest

  1. Expected yield per acre (based upon specific planting density). 20 MT/Ha.

  2. Timing based upon yields. 12 months.


Maturity based on cormel size. Harvested 8-12 months after planting, depending mainly on desired cormel size and on market conditions. In some areas, cocoyam can be harvested when most of the leaves begin to turn yellow.


Methods of Harvest

Before harvest the foliage is cut with a rotary mower and a disc brakes the furrow down. A modified potato harvester is then used to lift the corms and cormels from the soil. The one-row potato digger brings the cormels to the surface where they are selected, cleaned and packed into 50 lb wooden boxes, all without the aid of machinery. The boxes are later hauled to the packing shed. The planting material is selected by hand and cut with a machete. It is then thrown into a box or piled for curing until the cut surface has suberized.

In the packing-shed wash with a machine which first removes most of the soil loose, then washes the roots with a circular brushes, and thirdly selects by size and packs the cormels with the help of hand labor. A typically-sized machine produces about 80 50 lb boxes per hour with the help of seven laborers.

Insects

Aphids (Aphis gossypii). Control with pyrethrum.
Whitefly (Bemisia tabaci). Control with malathion.

Market/Uses

Availability

Year-round from Florida, Puerto Rico, Dominican Republic and Costa Rica.

Worldwide production of cocoyam is: Africa, 60%; Asia 32%; and Caribbean <8%, for a total of 8 million MT.

US Costs of Production

In 1981 total costs of production in Southern Florida were estimated at $1,664 per acre with the following distribution of costs:

  1. Land Preparation (2%)

  2. Planting/Seed Costs (6%)

  3. Growing (Fertilizer 11%, weed control 17%, irrigation 7%).

  4. Harvesting (13%)

  5. Packing (16%)

  6. Fixed costs (17%).

Planting

  1. Planting material. Pieces of corms (150 g or more). The upper section of the crown of the corm is used as planting material, and is selected from the farmer's previous crop.

  2. Preplanting treatment. Seed pieces should be cured before planting. Treat all planting material in a fungicide dip made up of Metalaxyl 1 g a.i. to 1 l of water (10 g Ridomil MZ 58/l of water). Air dry for at least two hours. Do not store the pl anting material for more than 2 weeks. Herbicides used include Diuron, atrazine, and linuron. Mulching (organic) is commonly recommended.

  3. Depth of Planting. Planting is either by hand labor or from a tractor pulled planter. Plant 5-7 cm beneath the soil level.

  4. Timing of planting (crop cycle). In the Caribbean-Florida area the best planting time is in the cool season between December and April, but plantings can be made any time during the year if moisture is adequate. In Florida malanga is planted in re gular intervals from November through June. Seed pieces germinate after 20-30 days after planting.

  5. Planting density (expected germination). In Florida plant at 15,000 plants per hectare. 100% germination if good quality seed is utilized.