CASTOR TECHNICAL

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Introduction

Castor (Ricinus communis L.) is generally grown for its oil-yielding seeds. The oil content of the seeds varies from 35-58 per cent in different varieties, the average being about 47 per cent. Castor-oil is being used widely for various purposes. It is used as a lubricant in high-speed engines and airplanes, in the manufacture of soaps, transparent paper, printing-links, varnishes, linoleum and plasticizers. It is also used for medicinal and lighting purposes. The cake is used as a manure and plant stalks as fuel or as thatching material or for preparing paper pulp. In eri silk-producing areas, leaves are fed to eri silkworms.

 
Variety

The varieties differ in the branching habit of the plants, colour of the stem and branches (red and green), the nature of capsules (smooth or spiny), duration (early or late) and the size of seed. The following are the principal improved varieties of castor recommended for cultivation in different states:
Name of Variety Name of State
Aruna, Bhagya, Saubhagya, Dwarf Mutant, Short Mutant Andhra Pradesh
H.C. 6, Rosy Karnataka
Girija (S-28-2), Maharashtra
CH –1 Haryana
S.A.- 2 Tamil Nadu
GCH –3, J-44, GAUC –1 Gujarat
Type –3, Tarai-4 Uttar Pradesh
Punjab Castor –1 Punjab
EB-16-A Bihar
W.B.-1 West Bengal

 
 Varietal Improvement

According to the Department of Agricultural Research and Education, ICAR, Government of India, DCH 177, a hybrid identified for release in 1997-98, has been found promising against botrytis, an important disease in rainfed castor-growing areas. Insect-pathogenic fungus Nomuraoea rileyi as oil emulsion when filed tested against Spodopetra litura on castor and groundnut gave promising results. Fungus formulation as an oil emulsion confers increased shelf-life as well as field persistence. The fungus can be multiplied in a cost-effective way on solid substrates such as crushed sorghum, barley and semi-synthetic media. All isolates are not amenable for growth on solid substrates. Development of protocols for its cost-effective multiplication and identification of virulent isolates amenable for multiplication on these solid substrates at the Directorate of Oilseeds Research make this fungus an agent of promise for managing major noctuid pests in near future.

 
Weed Control

Conditions during rainy season are conducive to rapid and luxuriant growth of weeds. Weeds compete with the plants in the early stage of growth. To keep the weeds down; two hand weedings, one at 30 days of crop growth and the other after 60 days of crop growth should be given. Eptam at the rate of 3-4 kg a.i. per hectare incorporated in the seedbed three weeks prior to planting gives good control of annual grasses and broad leaved weeds.

 
Pest Management
The castor semi-looper (Achoea janata L.) and the capsule-borer (Dichocrocis puntiferalis) are the two most serious pests of castor. Dusting Fenvelerate .4% in early stages or spraying 0.44% Ekalax or 0.1% Carbary1 or 0.05% Parathion on the crop will give an effective control of the
se pests.
The seedling blight (Phytophthora colucasiae Racib. emend. Thomas & T.S. Ramkar) and Alternaria blight Alternaria ricini (Yoshi) Hansford cause serious losses to this crop. The sowing of the crop in low-lying and water-logged areas should be avoided to prevent the seedling blight from appearing. For alternaria blight, seed treatment with Thiram at the rate of 3 g/kg of seed is recommended.
 
Important hints for getting maximum yields
  1. Recommended variety for a particular area should be chosen.
  2. Seed treatment with Thiram (3 g/kg of seed) should be done before sowing to prevent the attack of root-rot and alternaria blight.
  3. Sowing should be done at the right time recommended for different agro-climatic conditions. Sowing should be done with proper spacings recommended for different regions.
  4. The recommended fertillizer schedule for the region should be adopted.
  5. Proper, timely and adequate plant-protection measures should be adopted to save the crop from insect pests and diseases.
  6. Two to three intercultures should be done to provide aeration for the root-system and to keep the crop free from weeds.
  7. The nipping of branches increases the size of the main spike and induces early maturing.
  8. Harvesting must be done at the right time, as too early or too late harvesting results in reduced yield, oil and shattering of seed respectively.