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Ricinus communis L.


Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Toxicity
  5. Description
  6. Germplasm
  7. Distribution
  8. Ecology
  9. Cultivation
  10. Harvesting
  11. Yields and Economics
  12. Energy
  13. Biotic Factors
  14. References


Castorbean is cultivated for the seeds which yield a fast-drying, non-yellowing oil, used mainly in industry and medicines. Oil used in coating fabrics and other protective coverings, in the manufacture of high-grade lubricants, transparent typewriter and printing inks, in textile dyeing (when converted into sulfonated Castor Oil or Turkey-Red Oil, for dyeing cotton fabrics with alizarine), in leather preservation, and in the production of 'Rilson', a polyamide nylon-type fiber. Dehydrated oil is an excellent drying agent which compares favorably with tung oil and is used in paints and varnishes. Hydrogenated oil is utilized in the manufacture of waxes, polishes, carbon paper, candles and crayons. 'Blown Oil' is used for grinding lacquer paste colors, and when hydrogenated and sulfonated used for preparation of ointments. Castor Oil Pomace, the residue after crushing, is used as a high-nitrogen fertilizer. Although it is highly toxic due to the ricin, a method of detoxicating the meal has now been found, so that it can safely be fed to livestock. Stems are made into paper and wallboard (Reed, 1976).

Folk Medicine

Considered anodyne, antidote, aperient, bactericide, cathartic, cyanogenetic, discutient, emetic, emollient, expectorant, insecticide, lactagogue, larvicidal, laxative, POISON, purgative, tonic, and vermifuge, castor or castoroil is a dangerous ingredient in folk remedies for abscess, anasarca, arthritis, asthma, boils, burns, cancer, carbuncles, catarrh, chancre, cholera, cold, colic, convulsions, corns, craw-craw, deafness, delirium, dermatitis, dogbite, dropsy, epilepsy, erysipelas, fever, flu, gout, guineaworm, headache, inflammation, moles, myalgia, nerves, osteomyelitis, palsy, parturition, prolapse, puerperium, rash, rheumatism, scald, scrofula, seborrhea, skin, sores, stomachache, strabismus, swellings, toothaches, tuberculosis, tumors, urethritis, uteritis, venereal disease, warts, whitlows, and wounds. The oil and seed have been used as folk remedies for: warts, cold tumors, indurations of the abdominal organs, whitlows, lacteal tumors, indurations of the mammary gland, corns, and moles, etc. Castor-oil is a cathartic and has labor-inducing properties. Ricinoleic acid has served in contraceptive jellies. Ricin, a toxic protein in the seeds, acts as a blood coagulant. Oil used externally for dermatitis and eye ailments. Seeds, which yield 45–50% of a fixed oil, also contain the alkaloids ricinine and toxalbumin ricin, and considered purgative, counter-irritant in scorpion-sting and fish poison. Leaves applied to the head to relieve headache and as a poultice for boils. (Duke and Wain, 1981).


Per 100 g, the leaves are reported to contain on a zero-moisture basis, 24.8 g protein, 5.4 g fat, 57.4 g total carbohydrate, 10.3 g fiber, 12.4 g ash, 2,670 mg Ca, and 460 mg P. The seed contains 5.1–5.6% moisture, 12.0–16.0% protein, 45.0–50.6% oil, 3.1–7.0 NFE, 23.1–27.2% CF, and 2.0–2.2% ash. Seeds are high in phosphorus, 90% in the phytic form. The castor oil consists principally of ricinoleic acid with only small amounts of dihydroxystearic, linoleic, oleic, and stearic acids. The unsaponifiable matter contains b-sitosterol. The oil-cake from crushing whole seeds contain 9.0% moisture, 6.5% oil, 20.5% protein, 49.0% total carbohydrate and 15.0% ash. The manural value is 6.6% N, 2.6% P2O5, and 1.2% K2O (C.S.I.R., 1948–1976). There are 60 mg/kg uric acid and 7 ppm HCN in the seed. The seeds contain a powerful lipase, employed for commercial hydrolysis of fats, also amylase, invertase, maltase, endotrypsin, glycolic acid, oxidase, ribonuclease, and a fat-soluble zymogen. Sprouting seeds contain catalase, peroxidase and reductase.


The seeds contain 2.8–3% toxic substances, 2.5–20 seed killing a man, 4 a rabbit, 5 a sheep, 6 an ox, 6 a horse, 7 a pig, 11 a dog, but 80 for cocks and ducks. The principal toxin is the albumin, ricin. However, it produces antigenic or immunizing activity, producing in small doses an antitoxin analagous to that produced against bacteria.


Coarse perennial, 10–13 m tall in the tropics, with the stem 7.5–15 cm in diam., but usually behaves as an annual in the temperate regions 1–3 m tall; stems succulent, herbaceous, very variable in all aspects; leaves alternate, orbicular, palmately compound, 1–6 dm broad, with 6–11 toothed lobes, glabrous; flowers numerous in long inflorescences, with male flowers at the base and female flowers at the tips; petals absent in both sexes, sepals 3–5, greenish; stamens numerous, 5–10 mm long; ovary superior, 3-celled with a short style and 3 stigmas; fruit a globose capsule 2.5 cm in diameter, on an elongated pedicel, usually spiny, green turning brown on ripening, indehiscent in modern cultivars, usually containing 3 seeds; seeds ovoid, tick-like, shiny, 0.5–1.5 cm long, carunculate, vari-color with base color white, gray, brownish, yellow, brown, red, or black, with the outer pattern gray or brown to black, the pattern varying from fine to coarse, veined or finely dotted to large splotches, poisonous and allergenic, possibly fatel, from 1,000 to 11,000 per kg, commercial varieties having 2200 to 3200 per kg (Reed, 1976).


Reported from the African Center of Diversity, castorbean or cvs thereof is reported to tolerate bacteria, disease, drought, fungi, high pH, heat, insects, laterite, low pH, mycobacteria, nematodes, poor soil, salt, slope, smog, SO2, virus, weed, wind, and wilt. (Duke, 1978). Many cvs developed; two of the best commercial ones are: 'Conner' and 'Kansas Common', which give from 51.3 to 55.6% oil. (2n = 20)


Probably native to Africa, Castorbean has been introduced and is cultivated in many tropical and subtropical areas of the world, frequently appearing spontaneously.


Ranging from Cool Temperate Moist to Wet through Tropical Desert to Wet Forest Life Zones, castorbean is reported to tolerate annual precipitation of 2.0 to 42.9 dm (mean of 68 cases = 12.7) annual temperature of 7.0 to 27.8°C (mean of 68 cases = 20.4) and pH of 4.5 to 8.3 (mean of 29 cases = 6.5). Grows best where temperatures are rather high throughout the season, but seed may fail to set if it is above 38°C for an extended period. Plant requires 140–180 day growing season and is readily killed by frost. Irrigated crops require 2–3.5 acre-feet of water to produce satisfactory yields. High humidity contributes to the development of diseases. Plants do best on fertile, well-drained soils which are neither alkaline nor saline; sandy and clayey loam being best.


Castor is propagated entirely by seed treated to resist disease. Seeds retain their viability 2–3 years. After seedbed has been deeply cultivated, seed of the dwarf cvs in mechanized countries are planted 3.7–7.5 cm deep in rows 1 m apart; seeds about 25 cm apart in the rows; at rate of 15 kg/ha. For unmechanized societies which prefer larger cvs, seeds are planted 60 by 90 cm apart, 2–4 seeds per hole, and then thinned to one plant; this gives about 30,000 plants/ha. Cultivate shallowly until 0.6–0.9 m high. Irrigation is usual practice in the United States; in India castor is a dryland crop. Castor exhausts the soil quickly. In the United States 45–135 kg/ha of nitrogen is added in split applications. Leaves, stalks and seed hulls are disked into the field following harvest. In India 89 kg/ha of nitrogen gives the highest yields. Where phosphorus is deficient, 40–50 kg/ha of P2O5 is recommended. In Australia 200 kg/ha of superphosphate is applied. Furrow irrigation is preferred, but subirrigation reduces weed problems. Normally irrigation commences after plants have 6–8 leaves; overirrigation on heavy soils should be avoided; final irrigation should be 3–4 weeks before harvest. In the United States 1,500 to 2,000 cu m of water per hectare is applied during the growing season. In Brazil 2,400 cu m of water is applied during the 3 months between flowering and harvest, with about 400 cu m being applied at each irrigation at 15 day intervals. Seed may be planted by hand or with a corn planter with special plates, after the soil has become warm and out of danger of frost. Time varies with the locality; Illinois, early May; Venezuela, June–July; Australia, August–December; Morocco, March; Brazil (south), September–November; Brazil (north), January–March; India, July; Taiwan, August–September or April–May. For seed increase, castor should be planted on fallow land, and should not follow small grains or another castor crop. In India it is rotated with ragi, groundnuts, cotton, dryland chillies, tobacco or horsegram (Reed, 1976).


Non-mechanized societies prefer shattering cvs, as opposed to the non-dehiscent dwarf strains developed in the United States. Fruits are harvested when fully mature and the leaves are dry, in about 95–180 days depending on the cv. In tropics, harvest is from wild or native plants. Planting and harvesting may be done by hand methods or be completely mechanized. Harvesting should begin before rainy season in tropical regions, but in dry regions it is best to harvest when all fruits are mature. In India fruit is picked in November; in the United States harvesting begins in October. In the tropics most harvesting is by hand; the spikes are cut or broken off, the capsules stripped off into a wagon or sled, or into containers strapped on the workers. Unless the capsules are dry, they must be spread out to dry quickly. In India fruits are collected and spread in piles to dry in the sun until they blacken. In the United States drying may be accomplished by frost or by the use of defoliants; chemical defoliants are also used in Australia. In South Africa and Australia modified wheat headers are used for harvesting; in the United States more expensive harvesters are used which shake capsules from plants by jarring plants at their bases. Relative humidity of 45% or less is required for efficient operation with mechanical harvesters. Seed capsules shatter easily in most cvs. Some indehiscent varieties are threshed by ordinary grain thresher at 400–800 r.p.m. cylinder speed. After harvesting, seeds must be removed from the capsules or hulls, usually with hulling machines if capsules are dry. Percentage of seed to hull averages 65–75, depending upon the maturity of the seed at harvest. In India seeds are beaten out with sticks, winnowed and screened to remove hulls and trash. In South Africa, Brazil and the United States seed is decorticated with special castorbean decorticators. When small amounts of seed are involved, they may be decorticated on a rubbing board. An ordinary thresher is rarely suitable since the beater bar or peg drums break up the soft seeds. Castor oil is manufactured by running cleaned seed through the decorticating machines to remove the seed coat from the kernel; the more complete this operation the lighter the oil. Castor seeds cannot be ground or tempered as flaxseed or soybeans. Unbroken or uncrushed seeds should be gotten to the press. Preheating may make heavy viscous oil more mobile. Seed is put in 'cage' press, and number 1 oil is obtained, which needs little refining but has to be bleached. Oil remaining in the press-cake is extracted by solvent methods and is called number III oil, which contains impurities, and cannot be effectively refined. Castorbean oil can be stored 3–4 years without deterioration.

Yields and Economics

Average seed yields range from 900–1000 kg/ha under irrigation, and 300–400 kg/ha without adequate moisture. Some improved open-pollinated varieties in Brazil and the United States yield 1,300 kg/ha, with exceptional yields up to 5,000 kg/ha. Average Indian yields are 560 kg/ha. Oil content of seeds varies from 35 to 55%, suggesting potential oil yields of 200–2,750 kg/ha. In February 1982, the U.S. Bureau of Census noted "surprising" castor oil consumption. In the U.S. nearly 4,000 MT of the oil was used, an increase of ca 1,500 MT over January. In April of 1982, prices ranged from 42 to 72 cents per pound (92 to $1.58/kg) depending on quality and grade (CMR, April 26, 1982). During and since World War II, castor production increased in South America, Thailand and Haiti. In 1952, about 50,000 kg of castor oil was imported in the United States, mostly from India, Belgium, West Germany, Holland, Peru, Manchuria, China, Argentina, Mexico, Brazil and Paraguay; and 65,000,000 kg of seeds, mostly from Brazil, Ecuador, Thailand, India, Haiti and Ethiopia. World production was 723,000 MT on 1,285,000 kg, yielding 560 kg/ha. Wholesale prices for beans in 1969 from India was 15.2 cents/kg and from Europe 16.6 cents/kg. In 1971 prices from Brazil were $293/T. Prices vary: Italy 93.1 cents/kg producer price; Spain 66.6 cents/kg, export price; and the United States 85.3 cents/kg, import price. In 1970 more than 469,000 MT of oil was produced in the world, representing about 1% of the oil market. The 1980 projection was for 554,000 MT, which is a 4.2% increase.


Gaydou et al. (1982) rank oilseeds more promising for energy in Malagasy than sugarcane and cassava. Castor was least promising of the four oilseeds, producing 1,200–2,000 liters oil/ha (equivalent to 11,300 to 18,906 kwh) compared to tung at 1,800–2,700 l, purging nut at 2,100–2,800 l, and oilpalm at 2,600–4,000 l/ha. They calculated ca 1,000 l ethanol for cassava and 2,500 for sugarcane. Yields of 5 MT seeds are reported. When the oil is expressed, the oil cake remaining amounts to 45–50% of production (Devendra and Raghavan, 1978). In some of the dwarf temperate trees (treated as annuals), the straw factor is not much more than one, but perennial tropical trees may have a standing biomass of 25 MT/ha or more. The hull residue is calculated at 0.25 times production. Hulls have about the same fertilizer value as fresh barnyard manure.

Biotic Factors

Castor bean is both self- and cross-pollinated by wind, varying from 5–36% depending on the weather conditions. Pollen sheds readily between 26–29°C, with a relative humidity of 60%. For single cross hybrid seed production, strains giving a 1:1 ratio or pistillate and heterozygous monoecious plants are used, the latter being rogued 1–5 days before flowering begins. Three-way cross hybrids can also be used. For open pollinated types, roguing of all off-types is done after the last cultivation, and for pure seed production isolation necessity depends on the wind velocity. For hybrid and open pollinated types in the United States, stands are isolated 300–720 m, but in areas of less wind velocity, less distance may be sufficient. Fungi known to attack Castorbean plants include: Alternaria compacta, A. ricini, A. tenuis, A. tenuissima, Aspergillus itaconicus, A. niger, A. quercinus, Botrydiplodia manilensis, B. ricinicola, B. theobromae, Botryotinia ricini, Botrysphaeria ribis, Botrytis cinerea (Gary mold), Cephalosporium curtipes, Cercospora canescens, C. coffeae, C. ricinella, Cercosporella ricinella (Leaf spot), Cladosporium herbarum, Clitocybe tabescens, Colletotrichum bakeri, C. erumpens, C. ricini, Corticium solani, Didymella ricini, Diplodia natalensis, D. organicola, D. ricinella, D. ricini, Discosporella phaeochlorina, Epicoccum nigrum, Erysiphe cichoracearum, Fusarium moniliforme, F. orthoceras, F. oxysporum, F. sambucinum, F. semitectum, Gibberella pulicarus, Glomerella cingulata, G. ricini, Haplosporella manilensis, Lecanidion atratum, Leveillula lanata, L. taurica, Macrophomina phaseoli, Macrophoma phaseoli, Ph. ricini, Macrosporium cavarae, M. ricini, Melampsora euphorbiae, M. ricini, Melampsorella ricini, Mecrostroma minimum, Mucor fragilis, Mycosporella ricinicola, M. tulasnei, Myrothecium roridum, Oidiopsis taurica, Peniophora cinerea, Phoma macropyrena, Ph. ricini, Phomopsis ricini, Ph. ricinella, Phyllosticta bosensis, Ph. ricini, Phymatotrichum omnivorum (Root rot), Physalospora abdita, Ph. propinqua, Ph. rhodina, Ph. ricini, Ph. obtusa, Phytophthora cactorum, Ph. cinnamomi, Ph. palmivora, Ph. parasitica, Pleospora herbarum, Pythium aphanidermatum, P. debaryanum, P. gracile, P. intermedium, P. proliferum, P. ultimum, P. vexans, Rhabdospora ricini, Rhizoctonia solani, Schiffnerula ricini, Schizophyllum commune, Sclerotinia fuckeliana, S. minor, S. ricini, S. sclerotiorum, Scierotium rolfsii, sphaceloma ricini. The following bacteria also cause diseases: Agrobacterium tumefaciens, Bacterium lathyri, B. ricini, Pseudomonas solanacearum, Xanthomonas ricini, X. ricinicola. Striga lutea parasitizes the plants. Nematodes isolated from Castorbean include: Aphelenchoides asterocaudatus, A. bicaudatus, A. subtenuis, Helicotylenchus cavenssi, H. pseudorobustus, H. schachtii, Meloidogyne arenaria and var. thamesi, M. hapla, M. incognita, M. incognita acrita, M. javanica, M. thamesi, Merlinius brevidens, Pratylenchus brachyurus, P. neglectus, P. pratensis, P. scribner, P. vulnus, P. zeae, Radopholus similes, Scutellonema clathricaudatum, Tricephalobus longicaudatus, and Tylenchorhychus mashhoodi (Golden, p.c. 1984). Several insects are pests. In India the Capsule borer (Dichocrocis punctiferalis) bores into young and ripening capsules; and the Castor semilooper (Achoea janata) are the worst pests. In Tanganyika damage by capsid and myrid bugs are a limiting factor causing immature fruit to drop. Green stinkbugs, leaf-hoppers, leaf-miners and grasshoppers are pests that feed on the leaves. Most insects may be controlled by insecticides. Because some of the varieties are quite tall, wind storms are a potential hazard to a crop.


Complete list of references for Duke, Handbook of Energy Crops
Last update Friday, January 9, 1998 by aw