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Basil

R Dinesh Indian Institute of Spices Research

Calicut, Kerala, India 1.0 Introduction Basil, French basil, or sweet basil (Ocimum basilicum L.), a tender annual is a popular herb

known for its flavorful foliage. The term Basil is collectively used to describe plants of the genus

Ocimum, Family Lamiaceae (formerly Labiatae). The common names are Sweet basil, Common

Basil, French Basil, Basil and Bush Basil (Hortus Third, 1986; Simon et al., 1990a; Hornok,

1992).

Although several ornamental varieties are sold commercially, basil is primarily cultivated for its

aromatic leaves, which are used fresh or are dried for use as flavouring agent. Sweet basil is

reputed to be the sweetest in flavour among the basil species and is the darkest in colour. The

fresh or dried leaves add a distinctive flavor to many foods, such as Italian style tomato sauces,

pesto sauce and salad dressing. The essential oils and oleoresins are extracted from leaves and

flowers and used for flavoring in liqueurs and for fragrance in perfumes and soaps. During the

course of medicinal plant history basil has been both praised and excoriated. Early herbalists

asserted that basil damaged the internal organs, the eyes and caused insanity. Subsequent writers

argued that basil did none of these things, but was good both as a condiment and for a variety of

medicinal purposes (Low et al., 1994).

2.0 Composition and uses

As with many herb oils, the characteristics of basil oil changes between countries and plant parts

(De Masi 2006; Telci et al., 2006). This is most likely a result of different environmental

conditions and different cultivars. "True" sweet basil oil is a colourless or pale yellow liquid with

a light, fresh sweet-spicy sent and balsamic undertone (Lawless, 1992). Exotic basil oil which

comes from the plant commonly known as "bush basil", taxonomically classified as Ocimum

basilicum, is described as having a yellow or pale green colour, with a slightly course sweet

herbaceous odour, and a camphoraceous tinge (Lawless, 1992).

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The main oil constituents of "true" sweet basil are linalool (40-45%), methyl chavicol (23.8%),

and small amounts of eugenol, limonene and citronellol among others (Lawless, 1992). Bush

basil is mainly methyl chavicol (70-88%) with small amounts of linalool, cineole, camphor,

eugenol, limonene and citronellol (Lawless, 1992). However, many of these constituents are

variable depending on the country of origin and the plant history (Table 1).

Table 1. Chemotaxonomic classification of Ocimum basilicum based on the U.S.D.A. germplasm

collection (adapted from Simon et al., 1990a).

Plant number or Cultivar name

Predominant Constituents Country of Origin

175793 linalool Turkey 368699 linalool, 1,8-cineole Yugoslavia 358465 linalool, geraniol Yugoslavia 174285 linalool, methyl chavicol Turkey 190100 methyl chavicol, linalool Iran 253157 methyl chavicol, citral Iran 170579 methyl cinnamate, and Z

isomer Turkey

170579 methyl chavicol, methyl chavicol, linalool

Turkey

Purdue selection methyl eugenol Thailand

Twelve aroma constituents of basil were examined for their antioxidant activities using the

aldehyde/carboxylic acid assay. Eugenol, thymol, carvacrol, and 4-allylphenol showed stronger

antioxidant activities than did the other components tested in the assay. They all inhibited the

oxidation of hexanal by almost 100% for a period of 30 days at a concentration of 5 g/ml. Their

antioxidant activities were comparable to those of the known antioxidants, -tocopherol and

butylated hydroxy toluene (Lee et al 2005).

The value of its essential oil in the international market, however, depends on the percentage of

linalool. Studies on the morphological and agronomic characteristics (plant height, dry matter of

aerial parts, yield and essential oil content) of 55 O. basilicum, O. sanctum [O. tenuiflorum] and

O. gratissimum genotypes from the Ocimum Germplasm Bank of the Universidade Federal do

Sergipe, Brazil, indicated wide genetic variation among genotypes for all the morphological and

agronomic traits evaluated. The essential oil content and yield of genotypes ranged from 0.202 to

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2.536 ml/100 g and from 1.103 to 21.817, respectively (Blank et al., 2004).

Aroma compounds in the extracts of basil leaves (Ocimum basilicum L.) were identified by gas

chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The major aroma

constituents of basil were 3,7-dimethyl-1,6-octadien-3-ol (linalool; 3.94 mg/g), 1-methoxy-4-(2-

propenyl) benzene (estragole; 2.03 mg/g), methyl cinnamate (1.28 mg/g), 4-allyl-2-

methoxyphenol (eugenol; 0.896 mg/g), and 1,8-cineole (0.288 mg/g) (Lee et al 2005).

Linalool, methyl chavicol, eugenol, bergamotene, and methyl cinnamate were found to be the

dominant volatile components, the relative content of which was found to enable differentiating

between the basil cultivars examined. The relative content of some sesquiterpenes, hydrocarbons

benzenoid compounds, and monoterpene hydrocarbons was lower in dried and frozen leaves as

compared to fresh basil leaves (Klimnkov et al., 2008).

Oil Types

European type

Distilled from O. basilicum grown in Europe and America and commonly known as oil

of Sweet Basil. Its major constituent is methyl chavicol and linalool, but no camphor. It is

highly prized for its fine odour.

Reunion type

Distilled originally in Reunion Islands. The oil contains methyl chavicol and camphor but

no linalool.

It possesses a camphorraceous by-note and is considered inferior to the European oil.

Methyl cinnamate type

Distilled in Bulgaria, Sicily, Egypt, India and Haiti. It contains methyl chavicol, linolool

and substantial amount of methyl cinnamate but no camphor.

Eugenol type

Distilled in Java, Seychelles, Samoa and the Commonwealth of Independent States

(esrtwhile USSR). It contains eugenol as the main constituent.

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Sweet basil (Ocimum basilicum) has several culinary, ornamental, medicinal and aromatic uses

(Blank et al., 2004) and sold as a fresh herb and as a dried spice (Raimondi et al., 2006) It is a

source of essential oils and aroma compounds (Simon et al. 1984, 1990b), a culinary herb, and an

attractive, fragrant ornamental (Morales et al. 1993; Morales and Simon 1996). The seeds

contain edible oils and a drying oil similar to linseed (Angers et al. 1996). Extracts of the plant

are used in traditional medicines, and have been shown to contain biologically active constituents

that are insecticidal, nematicidal, fungistatic, or antimicrobial (Simon 1990; Albuquerque 1996).,

Besides being a culinary herb, basil is a well-known source of flavouring principles (Petropoulos

et al., 1995; Javanmardi et al., 2003; King and Duineveld, 2006) and therefore is recognized as

an important herb in cooking to flavour Italian, Mediterranean and Thai dishes and in tomato and

pesto sauces. Basil is also good with fish, poultry, pasta, rice, tomatoes, cheese and eggs. Dried

leaves and tender four-sided stems of this plant are used as a spice for flavouring and for the

recovery of essential oil. The flavour is warm, sweet and somewhat pungent and peculiar. The

odor of sweet basil is aromatic, fragrant and sweet. Basil is used as a condiment in a number of

countries, especially in southern European countries, U.S.A. and Australia (Simon et al., 1990a).

Essential oil and oleoresin are also extracted from the leaves and flowering tops by steam

distillation and used in place of the dried leaves for flavoring purposes (Simon, 1985).

Basil oil is also used to flavour dental and oral products, in fragrances and for traditional

medicines (Guenther, 1950; Simon et al., 1990a). The two minor components of the oil -

juvocimene I and II are reported to act as juvenile hormone analogs (Simon et al., 1990a). The

extracts from basil also possess excellent antioxidant properties (Javanmardi et al., 2003;

Hinneburg et al., 2006; Juntachote et al., 2006; Kivilompolo and Hytylinen, 2007) and is also a

potential source of anthocyanins (Simon et al., 1999).

A tea is made from the leaves (zcan et al., 2008) and used for nausea, gas pains and dysentery.

Basil's effectiveness as a carminative has been established, and research shows that extracts of

the plant inhibit organisms that can cause dysentery (Low et al., 1994). When used as a

companion plant, basil is reported to increase the growth of peppers and the growth and flavour

of tomatoes.

3.0 History and origin

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Basil is a member of the Lamiaceae (mint) family and is native to Asia and India where it is

considered sacred. It is indigenous to the lower hills of the Punjab and Himachal Pradesh and is

cultivated throughout India. Basil is now cultivated commercially in Europe, Africa, Asia and the

United States, but the main center of diversity appears to be Africa (Paton 1992).It is grown as

an ornamental plant and cultivated commercially for its green, aromatic leaves, which are used

fresh or dried as a flavoring or spice. In recent times Basil has become a popular condiment, and

is naturalised in many parts of the world expanding from its original Asian origin. In Australia

Basil is widely grown as a condiment, and has naturalised in Queensland (Low et al., 1994)

4.0 Botany

Basil is glabrous or glabrescent annual with leafy stems and thin, branching roots and reaches a

height of up to 60 cm at maturity. It is a summer annual from a tropical origin in the old world

(Hortus Third, 1986). Sweet basil leaves are yellow-green to dark green, depending on soil

fertility, and are about 3.75-5.0 cm long. Leaves are ovate to ovate elliptic, 7-13 cm long,

generally cuneate. When dried they turn brownish-green, whole and broken, brittle, curled or

folded together. The flower infloresence is a racemose, and the corolla is about 8 mm long, white

or purplish. The tiny seeds are dark brown. Sweet basil bears white flower spikes which bloom

from July to August.

The leaves have numerous dot-like oil glands in which the aromatic volatile oil of the herb is

contained. The herb bears clusters of small, white, two-lipped flowers in raceme fashion

Since the plant is very variable and its botanical nomenclature is complicated, several

designations have often been assigned to one or the same type. Polymorphism and cross-

pollination under cultivation have resulted in a number of sub-species, varieties and races

differing in height, growth habit, degree of heaviness and colour of stems, leaves and flowers.

Hence, some forms and types have been confused with other species.

5.0 Classification and varieties There are between 50 and 150 species of herbs and shrubs in the genus Ocimum, differing in

growth, habit, colour, and aromatic composition (Simon, 1989; Simon et al., 1990a), making the

botanical identification of Basil difficult (Hortus Third, 1986). They differ in growth habit,

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cohort and aromatic composition. Ornamental types of basil are commercially available and

include types with purple foliage (i.e. Dark Opal) or varying growth habits (i.e. bush basil).

Basil for the fresh market should have a sweet flavor and dark green foliage. Commercially,

there are three major types of basil having essential oil or dried leaves as their end product.

French basil, reputed to be sweetest in flavor and darkest in color, is the most valued. American

basil, noted for its rich color, sweet flavor, cleanliness, and uniformity of particle size, is

considered to be of very high quality. Egyptian basil also known as Reunion or African basil has

fragrance of camphor and different flavor and so is considerably less expensive.

While basil seed is plentiful, care must be observed in obtaining a type that has desirable

characteristics. Because several basil types may be mixed together either by a seed house or

processor to achieve a desired blend, any collected seeds that are later sown may vary in their

growth, development, and aromatic properties.

Many types of basil are available, depending on use. For fresh market production, basil with

good flavor and attractive, dark green or purple foliage is selected. Sweet basil (Ocimum

basilicum L.) is the culinary classic. Italian, Lettuce Leaf and Opal are popular sweet basil

varieties. Scented basils, such as Lemon, Licorice and Cinnamon basil, are used fresh or dried in

potpourri, jellies, honeys, vinegars and baked goods. For production of dried leaves or essential

oils, French, American or Egyptian basil may be grown. There are also several ornamental type

basils.

There are numerous varieties of O. basilicum of which, four are identified in India. They are var.

album Benth (Lettuce-leaf basil), var. purfrascens Benth (violet red basil), and var. thyrsiflorum

Benth (common white basil). Curly leafed basil is considered most suitable for cultivation; it is

grown in France and is reported to give good yields of high quality oil.

6.0 Genetics/ breeding/ micropropagation Basil seed is available around the world, but the identification and purity of this seed is

questionable. The U.S.D.A., germplasm repository has an extensive collection of Basil (Ocimum

basilicum) cultivars, many of which have been both taxonomically and chemotypically

classified. A number of different chemotypes have been identified and field tested under U.S.

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growing conditions (Simon and Reiss-Bubenheim, 1987).

An efficient protocol has been developed for rapid micropropagation of Ocimum basilicum.

Multiple shoots were induced by culturing shoot tip explants excised from mature plants on a

liquid Murashige and Skoog (MS) medium supplemented with 5100 M of thidiazuron (TDZ)

for different treatment duration (4, 8, 12 and 16 d). The optimal level of TDZ supplementation to

the culture medium was 50 M for 8 d induction period followed by subculturing in MS medium

devoid of TDZ as it produced maximum regeneration frequency (78 %), mean number of shoots

(11.6 1.16) and shoot length (4.8 0.43 cm) per explant. The regenerated shoots rooted best on

MS medium containing 1.0 M indole-3-butyric acid (IBA). The micropropagated shoots with

well developed roots were successfully established in pots containing garden soil and grown in

greenhouse with 95 % survival rate. The regenerated plants were morphologically uniform and

exhibited similar growth characteristics and vegetative morphology to the donor plants (Siddique

and Anis, 2007).

An efficient plant regeneration protocol has also been developed for basil (Phippen and Simon,

2000). Explants from 1 month old seedlings yielded the highest frequency of 85% regeneration

with an average of 5.1 shoots per explant. The regeneration protocol was performed on three

basil varieties (Sweet Dani; Methylcinnamate; Green Purple Ruffles). Callus and shoot induction

was initiated on MS basal medium supplemented with thidiazuron (16.8 M) for approximately

30 d. Shoot induction and development were achieved by refreshing the induction medium after

14 d. The most morphogenetically responsive explants were from the first fully expanded true

leaves of greenhouse-grown basil seedlings. All developing bud tissue demonstrated temporary

anthocyanin expression; however, anthocyanin expression in Green Purple Ruffles remained

stable until maturity. Developing shoots were rooted in the dark on media with thidiazuron

removed. Within 20 d, rooted plantlets were transferred and acclimatized under greenhouse

conditions where they developed normal morphological characteristics. This is the first report of

a successful in vitro regeneration system for basil through primary callus.

A scale-up micropropagation technique enhanced accumulation of rosamaric acid in sweet basil.

The nodal explants with lateral buds and leaf-derived suspension cultures were cultured in 5 l

airlift bioreactors for three weeks, thereby increasing the fresh wt of suspension cultures 2.5-fold.

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Rosmarinic acid accumulated at 29 g g1 dry wt in the suspension culture but, for

micropropagated plants, it reached 178 g g1 dry wt (Kintzios et al., 2004)

7.0 Soil and climate Basils are native to tropical climes and are considered annuals in our climate because they are

hardy to only 32F. They require a minimum of four hours of direct sun per day. They should be

planted in a soil that is rich, loamy, and well-drained with a pH of 5.5 to 6.5. The soil needs to be

kept moist to hasten germination and to ensure a uniform stand, when plants emerge within two

weeks. Basils should not be planted outdoors until the warmth of frost free mid May because

these tender plants react unfavorably to cool, damp weather (DeBaggio Herbs, 2007)

8.0 Cultivation 8.1 Land preparation The land is prepared to good tilth by ploughing, harrowing and levelling. 10 tonnes of well rotten

FYM, 100 kg DAP and 100 kg muriate of potash per hectare are applied as basal dose. A better

option is to plant basil seed and seedlings in beds following a good fallow, ripping, discing, and

tilling with a rotary hoe fitted with bed formers. Beds can be spaced 60-90 cm apart and two

staggered rows (20-30 cm between rows) sown on each bed. Beds wider than 50cm with more

than 2 rows of plants can tend to show reduced middle row growth, as a result of light

competition. Basil needs full sun to achieve high leaf production levels. If excess shading occurs

the plants will etiolate and produce little leaf. High light conditions maximise the oil yield.

8.2 Seeds/planting material Basil may be cultivated either as a field-grown crop or in a greenhouse. It can be propagated

using seeds, cuttings or transplants, seeding or transplanting to the field once seedlings are more

advanced. To ensure a good crop, high-quality seed is important and should be purchased from a

reputable source. Quality, trueness to type, high germination percentage, and reliability are more

important than price when considering the purchase of seed. The optimum storage temperature of

basil seed is 5C, however, the seed does lose viability quickly. The germination rate of basil

seed should be 80 - 95%, and seed should not be used if the germination rate is below 70%

(Simon, 1989).

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Basil seed is large and is germinates easily, hence field establishment by direct sowing in a

nursery is a good production option. About 125 g viable seeds are required for one hectare (1000

seed weigh a little over 1 g). The seed germination starts 3 days after sowing and is practically

over in about 10 days. The seedlings are ready for planting after 4 - 6 weeks of sowing.

However, Basil is a frost tender annual, and in areas where the frost free period is short,

establishment by seedlings is more viable.

The large seed of Basil makes seeding in individual cells with a vacuum seeder relatively simple.

For small scale operations a home made vacuum seeder is suitable. A plastic box the size of the

seeding tray can have a plastic fitting attached to fit a household vacuum cleaner, the opposite

side should be drilled with 0.5mm holes positioned to correspond with the centres of each cell.

When the vacuum cleaner is on seeds will be held against the holes until placed over the seedling

tray, and the vacuum cut. This method can allow a large number of trays to be seeded in a

relatively short time (RIRDC Research Paper Series No 97/18, 1997).

For the planting of large areas of Basil, the cost of buying prepared seedlings from an established

nursery would be more economical than trying to produce seedlings in an under-equipped home.

Basil is also relatively easy to grow from cuttings, however, cuttings would only be used for

selection and breeding trials to increase the population of a selected line. The ease of seed

germination, and the annual nature of basil plants, does not make clonal establishment a viable

option.

8.3 Planting Basil can be direct seeded or transplanted to the field in late spring after all danger of frost has

passed. The germination rate of the seed should be 80-95%, and seed should not be planted if the

germination percentage is less than 70%. If the soil is heavy, the seed should be covered with an

anticrustant. The soil should be kept moist to hasten germination and to ensure a more uniform

plant stand. The seed is relatively small, and a good friable, well-tilled and uniform seedbed is

required for optimum plant establishment. Seeds should be planted only 1/8 - 1/4 inch deep. For

direct seeding, seed is planted only 3 to 6 mm deep at a spacing of 2.5 mm apart (8 to 10 per

inch). Hornok and Lenches (1992) recommend sowing basil seed at a depth of 0.5 cm using

about 2-3 kg of seed per hectare. Plant emergence should occur between 8-14 days. To

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encourage lateral branching and growth, the tops of transplants can be trimmed prior to field

planting, when they are about 6 inches tall.

The seedlings are planted at a spacing of 60 cm between the rows and 40 cm between the plants

in April - May or August - September. The field is irrigated on alternate days until plants

establish, thereafter the crop is irrigated at 5 - 7 day intervals during non-rainy periods. However,

the plant spacing for Basil varies from country to country, usually depending on the type of

machinery used. A good spacing is to grow basil in rows spaced 60 to 90 cm apart, with plants

spaced every 15cm in the row. Beds can also be used with two to three rows per bed. Rows

should be 30cm apart and the plants spaced between 15 -30 cm in the row (Simon, 1989). It is

not advisable to plant more than three rows per bed as shading will reduce growth in the centre

rows.

Basil is easy to grow but is very susceptible to cold weather. For any grower who wants an early

crop, seedlings should be started indoors by sowing seeds in trays or flats. While in the

greenhouse, plants can be trimmed to encourage branching and then transplanted into the field

when they have reached 15 cm in height, in about four to six weeks. Plants should be spaced 15

to 30 cm apart in rows which are 0.5 to 1.0 m apart, depending on the nature of the inter-row

cultivation equipment. Double-row plantings on beds between 0.5 and 1.2 metre wide increase

yields and held to shade out weeds. Large producers plant 70,000 to 84,000 plants per hectare

(30,000 to 35,000 per acre).

While the optimum population density is dependent upon the end use, a higher density can be

grown if compatible farm equipment is available for mechanical cultivation and seeding. Rows

24 to 36 inches apart, with plants spaced every 6 inches in each row, are recommended Basil can

also be planted in a bed of 3 rows 12 inches apart with 12 inches between rows. The distance

between the beds, ranging from 24 to 36 inches, is dependent on available equipment. Large

variations in growth and yield may occur due to climate conditions, plant type, and cultural and

management practices.

Weed control is critical during the establishment of basil plants. If weeds are not well controlled

during the fallow and cultivation periods, high labour and / or chemical controls will be

necessary.

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8.4 Fertilizers

It is generally suggested that 110 to 135 kilograms each of N, P2O5 and K20 per hectare (100 to

120 pounds per acre) be broadcast and incorporated at the time of planting. If more than one

harvest is made, a side-dressing with 16 to 33 kilograms N per hectare shortly after the first or

second cutting is recommended.

Split application of N is also recommended by fertilizing thrice with 50 kg urea per hectare each

time. First dose is given during transplanting, the second and third after one and two months of

transplanting. In Zn deficient soils, 25 - 50 kg Zinc Sulphate per hectare is applied. However, the

rates of fertilizer application will depend upon the soil type and the previous crops and fertilizer

applications. Over fertilizing basil sacrifices flavour for growth.

U.S. recommendations are to apply an N:P:K fertilizer ratio 1:1:1 at a rate of 120 kg per ha, then

sidedress with 20-30kg N per ha after the first harvest. Increased nitrogen levels will improve the

leaf biomass and crop colour, however, Hornok (1983) showed that moderate levels of nitrogen

and high levels of P increased the essential oil content. The oil composition of basil can be

changed by the use of unbalanced nutrient additions. Basil plants displayed a significant decrease

in their main components (menthol and linalool) as nitrogen levels were increased (Hornok,

1983; Adler et al., 1989). However, an increase in potassium caused an increase of menthol and

linalool, while varying phosphorous levels had no effect (Hornok, 1983). This ability to change

the chemical composition of the oil by various nutrient combinations is important when

supplying companies who require specific oil chemistry. In a study on the effect of N

fertilization on the growth, yield and essential oil content of basil, it was found that N

fertilization up to 300 kg ha1 increased yield of above-ground and leaf fresh biomass, leaf

essential oil yield, but it did not affect leaf-to-stem ratio, plant height and the number of

branchings per plant. The increase in essential oil yield induced by N fertilization depended on

an increase in both leaf essential oil concentration and leaf biomass (Sifola and Barbieri, 2006)..

Mulching is recommended for basil production because it ensures moisture retention, prevents

weed growth and keeps the foliage clean from the soil. The most commonly used mulch is black

plastic, which encourages an early first harvest by warming the soil in the spring.

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8.5 Irrigation

Basil should be treated as a leafy vegetable when considering water requirements and cannot

tolerate drought stress. During seedling establishment beds should be always moist but not wet,

and during growth the plants like to be in moist, well drained soil. Water needs to be applied

regularly throughout the growing season to maintain constant growth. Although basil may be

irrigated with a simple overhead sprinkler system, a regular and even supply of moisture via drip

irrigation is best. Plants grown with drip irrigation are less likely to develop foliar diseases than

sprinkle-irrigated plants because the foliage stays drier. Research has shown that growing basil

with drip irrigation and black plastic mulch results in high yields of high-quality, clean leaves.

8.6 Inter-cultivation

Weed control is critical because competition with weeds decreases the quality of basil leaves. To

keep weed populations low, high plant populations, shallow cultivation, or mulching should be

used. The field is kept free of weeds during the initial stages of crop growth and after first

harvest by manual weeding. To keep weed populations low, use high plant populations, shallow

cultivation, or mulch. Mulch, plastic or organic, also helps retain moisture in the soil and

prevents soil from being splashed onto the foliage.

Presently, high plant populations of basil coupled with mechanical cultivation are recommended.

Commercially labeled herbicides for weed control in basil fields are not available. The presence

of weeds in fresh or dried basil leaves decreases the quality of the finished product.

Mulching is a good method of controlling weeds, and basil plants do well under mulch,

responding to both organic and inorganic forms. Plastic mulch has been shown to increase the

production of basil (Ricotta and Masiunas, 1983; Davis, 1994). However, the high humidity also

increased disease incidence (Davis, 1994). Davis (1994) also tested a number of other mulchs

with mixed success; however, if mulch is used the basil plants are normally established as

seedlings, and this plus the mulch greatly increase the cost of production.

8.7 Harvest

Leaf cuttings of basil may be harvested from one to five times per season, depending on the area

involved and the length of the growing season. For small-scale production of fresh-market basil,

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the terminal whorls of leaves are cut from the stems. The basil should be refrigerated as soon as

possible after cutting, preferably in the field.

Harvesting of basil should occur in the morning after the dew has left the plants but before the

heat of the day. If it is necessary to wash the basil after harvest, a water temperature of 13C

(55F) would be preferred and the material needs to be dried completely.

A sickle-bar mower with adjustable cutting height is commonly used for harvesting large

plantings for dried basil production. Foliage must be harvested before the plants bloom. Basil

plants will seed and stop producing leaves if the flower spikes are not removed as they appear.

Leaf yields can range from 2.5 to 7.5 tonnes per hectare (one to three tons per acre) of dried

material or 15 to 25 tonnes per hectare (six to ten tons per acre) of fresh material in California.

The plant part harvested depends upon the projected use. Where basil is grown for its dried

leaves and the extraction of essential or volatile oil, it is cut just prior to the appearance of

flowers. In the Mediterranean area and in other countries with similar climates, basil is grown as

a short-lived perennial, and 3-5 cuttings or harvests per year are achieved. In the more temperate

zones basil may be cut only 1-3 times. The first harvest in this case is very low, and the second

occurs just prior to open bloom. Generally, basil is harvested for its leaves, sold fresh or dried.

The foliage should be harvested, but only above the bottom two to four sets of true leaves.

A sickle bar gerry mower with an adjustable cutting height can be employed to cut the herb.

Leaves can be harvested when needed. The foliage should be cut at least 4-6 inches above the

ground to allow for regrowth and a subsequent crop. To ensure a continuous supply of leaves, the

field harvests and/or planting dates can be staggered accordingly.

- Leaf yields range from 1 to 3 tons per acre dried or 6 to 10 tons per acre fresh. Foliage may be

harvested whenever four sets of true leaves can be left after cutting to initiate growth, but when

harvesting for fresh or dried leaves, always cut prior to bloom. Presence of blossoms in the

harvested foliage reduces the quality, and consequently price, of the fresh and dried product.

Frequent trimming helps keep plants bushy. For small-scale production of fresh-market basil, the

terminal 2- to 3-inch long whorls of leaves may be cut or pinched off once or twice a week. This

provides a high quality product with little stem tissue present. Basil can also be cut and bunched

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like fresh parsley. A sickle bar type mower with adjustable cutting height is commonly used for

harvesting large plantings for dried production.

8.7.1 Harvesting for oil

The production of Basil oil is a broad acre enterprise. The oil yield varies between cultivars and

countries, and is highest in flowering plants (Prakash, 1990). Besides, the oil yield also varies

with the method of harvest (Kothari et al., 2004).

Kothari S.K., Bhattacharya A.K., Ramesh S (2004) Essential oil yield and quality of methyl eugenol rich Ocimum tenuiflorum L.f. (syn. O. sanctum L.) grown in south India as influenced by method of harvest Journal of Chromatography A, 1054:67-72.

The timing of harvest is determined by the composition and quantity of oil in the plant. The oil

yield and oil components will change during the year, but when the oil yield and desired oil

components are at their maximum, harvesting should commence. However, it is not always

advantageous to harvest when the oil concentration is at its maximum. It has often considered

that basil should be harvested at the onset of flowering (Basker and Putievsky, 1978; Hornok and

Lenches, 1992), as this is when the essential oil content in the plant approaches its highest.

However, if the plants are harvested prior to flowering, a greater number of harvests are possible

during the season, and the overall yield of leaf and oil is higher (Basker and Putievsky, 1978).

Hence, the best time to harvest Basil is during flowering (full bloom). On average the oil yield is

around 0.4% (Prakash, 1990). A Basil plot in with irrigation could be harvested two to four times

a year. The actual process of harvesting can utilize a standard forage harvester which will cut the

stems and deposit the cut material into a trailing distillation bin. This reduces the need for double

handling of the material prior to distilling. It is not necessary to de-stem or chop the material as

this may cause oil loss and increase the cost of processing.

8.7.2 Harvesting for dried leaf

When harvesting for dried product more care is required than when harvesting for oil, and

mechanical methods employing a cutter bar set in front of a conveyer belt are often used. The cut

material falls on the belt and is lifted up to collection bins, thus reducing bruising; a 10 to 12 cm

stubble is left providing a number of growing points for regrowth. Another method is to mow the

15

Basil, allow it to partially dry, then windrow and pick up with conventional hay making

machinery (Hornok, 1992).

Following harvesting, the plant material may be washed to reduce soil and dust impurities, as

these will reduce the quality of the final product. If plants are grown on mulched beds the need to

wash the product is reduced. A blanching in boiling water is often combined with the washing

prior to drying to help maintain the dry colour (Rocha et al., 1993).

8.7.3 Harvesting for the fresh market Hand harvesting is the best method to collect plant material for the fresh market, as only top

quality leaves should be collected. The plants should be cut with a sharp knife or clippers, and

bunched. The bunches can be fastened with a rubber band and placed in cool boxes to start

removing field heat. A hand held hedge trimmer powered by a small petrol engine can be used,

reducing harvest time. Some form of sorting and classing is required after this form of cutting.

9.0 Pests and diseases Basil plants are susceptible to a number of fungal diseases which usually occur in wet humid

conditions (Simon, 1989). Davis (1994) describes how different mulches that maintained good

soil moisture cause significant plant losses, as a result of soft rot (Erwinia spp.). During

abnormally wet summers or wet weeks following irrigation, monitoring for disease outbreaks

would be necessary. Root and leaf soft rot are the main fungal disease, including Fusarium wilt

and the use of raised beds on free draining soil is the best control.

Though there are several insects and diseases that may infest the plant, but there are no pesticides

currently available for use on basil. Plants should therefore be monitored continually for the

presence of insects and diseases and preventive methods of using ridged beds and not irrigating

if there is a chance of rain are be the best production methods.

Therefore, prevention of disease through good cultural practices is the most effective means for

healthy crop production. To help prevent foliar fungal diseases, keep foliage as dry as possible

by watering early in the day so foliage dries quickly, or by using drip irrigation. To reduce soil

borne diseases, rotate herbs to different parts of the field each year and remove and destroy all

plant debris after final harvest.

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9.1 Diseases

A devastating basil wilt disease caused by a soilborne pathogenic fungus, Fusarium oxysporum f.

sp. basilicum (Elmer, 2001), was first discovered in the U.S. in 1991 and identified in N.C. in

1992. Plants infected with this disease usually grow normally until they are six to twelve inches

tall, then they become stunted and suddenly wilt. Initial symptoms usually include brown streaks

on the stems, discoloration of the internal stem tissue, and sudden leaf drop. Interestingly, only

sweet basil is affected. Some of the specialty basils, such as lemon basil and purple basil, show

some resistance to the disease.

The disease is introduced into fields, hydroponic systems, and greenhouse culture primarily

through contaminated seed. Growers should only buy basil seed that has been tested for the

fusarium wilt fungus. Currently, these tests involve growing out a large number of seed and

looking for disease symptoms. This does not guarantee that the seed will be free of infection, but

it greatly reduces the risk. If it is not possible to obtain tested seed, the seed should be soaked in

cold water for four hours followed by a heat treatment of 20 minutes in 133-136 degree F water.

Seed germination rates will probably be reduced by the hot water treatment, so a germination test

should be conducted on a small lot of the treated seed to determine how much seeding rates need

to be adjusted. Also, the hot water treatment causes a sticky layer to develop on the outer surface

of seed making it difficult to handle.

Once a field has become infested with the fusarium wilt pathogen, infective propagules may

persist in the soil for 8-12 years. During that time, growers should avoid growing sweet basil or

members of the mint family. Mints will not exhibit symptoms of the disease but may carry over

the inoculum from year to year. There are currently no products registered to help control this

disease. However, steaming with a soil-steaming machine and exothermic reaction by

incorporation into the soil of potassium hydroxide (KOH), a substance that causes an exothermic

reaction with water have been found effective against Fusarium oxysporum f.sp. basilici and

Sclerotinia minor on basil (Luvisi et al. 2006). The results show that steam combined with

exothermic reaction reduce the incidence of Fusarium wilt (77-96%) better than steam only (70-

89%). The control of Sclerotinia minor was better with potassium hydroxide (94-92%) than with

steam only (83-87%). Leaf spot disease probably caused by Cercospora guatemalensis Mueller

et Chupp has been observed in Chiba Prefecture (Japan) (Nishikawa et al. 2002).

17

9. 2 Insect pests

Javelin (Bacillus thuringiensis) is the only insecticide registered for use on basil in North

Carolina. It is a biological control that kills a variety of caterpillars. If other insect problems

become serious, other organic methods may be tried. Reflective mulches, beneficial insects,

insecticidal soaps, traps and hand-picking may give some level of control.

10. Post harvest technology and value addition

Only the highest quality basil with the best colour and aroma should be used for fresh-market

sales. Basil once harvested should be stored at 4.5 to 7C (40 to 45F); lower temperatures may

cause discolouration and deterioration. Dried Basil should have a bright green colour, hence it

should be dried quickly in order to inactivate the enzyme chlorophyllase which breaks down

chlorophyll turning the leaf yellow-brown. Heat can destroy this enzyme quickly. However

temperatures in excess of 40C will remove the volatile oils (Deans et al., 1992) reducing

flavour. The moisture content should be reduced to less than 13%. Following drying the product

should be packaged and sent to market without delay as the loss of volatile oil is continuous.

Current specifications for the importing of spices into the U.S.A. do not include Basil, either

whole or ground.

A good commercial sample of sweet basil should contain a minimum of 0.4% volatile oil, a

maximum total ash content of 15%, maximum acid insoluble ash of 1.0%, maximum moisture of

8% and total ether extractives, a minimum of 4% on moisture free basis.

Before drying, basil stalks should be cut 15 cm above the ground and the foliage stripped from

the stems. Drying needs to occur on a screen in a warm, dark, well-ventilated place. Dried leaves

should be stored in the dark in airtight containers.

Leaves should first be washed and cleaned, with weeds and extraneous materials removed. The

quality of basil is determined by color and aroma retention. For the fresh market, only the highest

quality plant material should be sold. Prior to milling or distillation, the leaves and/or flowering

tops should be dried at low' temperatures (below 40 C) to retain maximum color.

18

For fresh market sales, after harvest, wash and dry leaves and remove all weeds and flowers.

Only the highest quality basil with the best color and aroma should be used. Wholesale packs

may be prepared by filling perforated plastic bags with one pound of loose leaves. For retail

sales, small, uniform bunches of leaves may be tied and packaged. Keep all basil refrigerated

until sold. The optimum storage temperature is 40 to 450 F. Lower temperatures may cause

discoloration.

For a dried finished product, wash leaves, spread on screens, and sort out weeds and blossoms.

To retain maximum color, circulate warm air (less than 130 F) around the leaves until dry. Sun-

dried leaves tend to be brownish. Store in air-tight containers in the dark. For essential oil

production, cut basil should be field dried for 1-3 days prior to collecting and distillling.

11. Economics and marketing

Markets for the dried product need to be established before production begins as with any

agricultural product. While basil consumption in the US has increased eight-fold since 1960, the

market for herbs fluctuates greatly from year to year.

When deciding which varieties to grow, those which were in demand the previous year need to

be identified. Prices for herb products often vary from year to year, depending on supply and

demand for the product. In general, prices for culinary herbs in the US are more stable than those

for other herb products.

For small producers, fresh-market sales can be made to local restaurants, health food stores,

organic markets and gourmet groceries. Small-scale herb growers may also market value-added

products such as pesto, basil vinegar, and fancy-packed dried basil for sale in specialty shops.

Greenhouse herb plants can also be sold as herb bedding plants for transplanting to gardens.

http://www.newcrops.uq.edu.au/newslett/ncnl6154.htm Another development in herb production is fresh pot herbs. These are herbs produced in pots and

sold cheaply at supermarkets for use in kitchens. The herbs will provide a small volume of fresh

material to households while being an attractive ornamental plant. An economic plan of this form

19

of production based in Southern Queensland showed Basil plants could be ready for sale every 6

weeks in summer and 8 weeks in winter. The return on capital invested was estimated at 58.65%

when a range of herbs were produced in this way (Avard et al., 1982). However, basil will not

withstand temperature below 5C so sales during the winter months would be limited.

References Adler, P.R., Simon, J.E., Wilcox, G.E. (1989) Nitrogen form alters sweet basil growth and

essential oil content and composition. Journal of Horticultural Science 24 (5): 789-790. Angers, P., Morales, M/ R., Simon J. E. (1996). Fatty acid variation in seed oil among Ocimum

species. J. Am. Oil Chem. Soc. 73:393395. Avard, L., Story, G., Wentworth-Jackson, I. (1982) Six Herbs Development of a commercial

Programme. Australian Horticulture August:93-105. Basker, D. and Putievsky, E. (1978) Seasonal variation in the yields of herb and essential oil in

some Labiatae species. Journal of Horticultural Science 53:(3) 179-183. Blank, A. F., Carvalho Filho, J. L. S. de, Santos Neto, A. L. dos, Alves, P. B., Arrigoni-Blank,

M. de F., Silva-Mann, R., Mendona, M. da C. (2004) Morphological and agronomic characterization of basil accessions. Horticultura Brasileira, 22: 113-116.

Davis, J.M. (1994) Comparison of mulches for fresh market basil production. HortScience

29(4):267-268. De Masi L, Siviero P, Esposito C, Castaldo D, Siano F, Laratta B (2006) Assessment of

agronomic, chemical and genetic variability in common basil (Ocimum basilicum L.). European Food Research and Technology, 223: 273-281.

Deans, S.G. and Svoboda, K.P. (1992) Effects of drying regime on volatile oil and microflora of

aromatic plants. Acta Horticulturae 306:450-452. DeBaggio Herbs, 2007. 43494 Mountain View Drive, Chantilly, VA 20152, (703) 327-6976

(www.debaggioherbs.com).

Elmer W.H. (2001) Seeds as Vehicles for Pathogen Importation. Biological Invasions, 3: 263-271.

Guenther, E., (1950) The Essential Oils Vol 4, p 526, Van Nostrand, New York. Hinneburg I, Damien Dorman H.J, Hiltunen R (2006) Antioxidant activities of extracts from

selected culinary herbs and spices, Food Chemistry, 97:122-129.

20

Hornok, L. (1983) Influence of nutrition on the yield and content of active compounds in some essential oil plants. Acta Horticulturae 132: 239-247.

Hornok, L. (1992) The Cultivation and Processing of Medicinal Plants. John Wiley and Sons,

New York. Hornok, L. and Lenches, O. (1992) Sweet Basil. In: The Cultivation and Processing of

Medicinal Plants. (ed.) Hornok, L.. John Wiley and Sons, New York. Hortus Third (1986) A Concise Dictionary of Plants Cultivated in the USA and Canada.

Macmillan, New York. Hortus Third (1986) A Concise Dictionary of Plants Cultivated in the USA and Canada.

Macmillan, New York.

Javanmardi J., Stushnoff C, Locke E, Vivanco JM (2003) Antioxidant activity and total phenolic content of Iranian Ocimum accessions. Food Chemistry, 83: 547-550.

Juntachote T, Berghofer E, Siebenhandl S, Bauer F (2006) The antioxidative properties of Holy basil and Galangal in cooked ground pork, Meat Science, 72: 446-456.

King B.M, Duineveld C.A.A (2006) Interactions of basil flavour compounds in tomato soups of varying Brix and acidity. Developments in Food Science, 43: 489-492.

Kintzios S, Kollias H, Straitouris E, Makri O (2004) Scale-up micropropagation of sweet basil (Ocimum basilicum L.) in an airlift bioreactor and accumulation of rosmarinic acid, Biotechnology Letters, 26: 521-523.

Kivilompolo M and Hytylinen T (2007) Comprehensive two-dimensional liquid chromatography in analysis of Lamiaceae herbs: Characterisation and quantification of antioxidant phenolic acids. Journal of Chromatography A, 1145, 155-164.

Klimnkov E, Holadov K, Hajlov J, ajka T, Poustka J, Koudela M (2008) Aroma profiles of five basil (Ocimum basilicum L.) cultivars grown under conventional and organic conditions. Food Chemistry, 107: 464-472.

Lawless, J. (1992) The encyclopaedia of Essential Oils. Element books Pty Ltd Longmead, Shaftesbury, Dorset.

Lee S-J, Umano K, Shibamoto T, Lee K-G. (2005) Identification of volatile components in basil (Ocimum basilicum L.) and thyme leaves (Thymus vulgaris L.) and their antioxidant properties.Food Chemistry Volume 91, 131-137.

Low, T., Rodd, T. and Beresford, R. (1994) Magic and Medicine of Plants. Reader's Digest Publications Australia.

21

Luvisi A, Materazzi A, Triolo E (2006) Steam and exothermic reactions as alternative techniques to control soil-borne diseases in basil Agron. Sustain. Dev. 26: 201-207.

Morales, M.R., Charles, D. J., Simon J. E. (1993). New aromatic lemon basil germplasm. In: J.

Janick and J.E. Simon (eds.), New crops. Wiley, New York. p. 632635. Morales, M.R. Simon J. E. (1996) New basil selections with compact inflorescence for the

ornamental market.. In: J. Janick (ed.), Progress in new crops. ASHS Press, Alexandria, VA, p. 543546.

Nishikawa J, Nakashima C, Kobayashi T (2002) Circular leaf spot of sweet basil caused by

Cercospora guatemalensis new to Japan, Journal of General Plant Pathology, 68: 46-48. zcan M. M, Ahmet nver A, Uar T, Arslan D (2008) Mineral content of some herbs and

herbal teas by infusion and decoction, Food Chemistry, 106: 1120-1127 Paton, A. 1992. A synopsis of Ocimum L. (Labiatae) in Africa. Kew Bul. 47:403435.

Petropoulos, G., Vlachou, A-M (1995) GLC analysis and comparison of the flavor of different populations of basil. Developments in Food Science, 37: 849-855.

Phippen WB, Simon JE (2000) Shoot regeneration of young leaf explants from basil (Ocimum basilicum L.) In Vitro Cellular & Developmental Biology - Plant, 36: 250-254.

Prakash, V. (1990) Leafy spices. CRC Press, Inc., Boca Raton, Florida, USA. Raimondi, G., Orsini, F., Maggio, A., De Pascale, S., Barbieri, G. (2006) Yield and quality of

hydroponically grown sweet basil cultivars. ISHS Acta Horticulturae 723 I International Symposium on the Labiatae: Advances in Production, Biotechnology and Utilisation

Ricotta, J.A., Masiunas, J.B. (1991) The effects of black plastic mulch and weed control

strategies on herb yield. HortScience 26(5): 539-541. RIRDC Research Paper Series No 97/18 (1997) A Commercial Herb Industry for Northern NSW

-An Infant Enterprise, Report for the Rural Industries Research and Development Corporation (Shirley Fraser and Jeremy P M Whish), Department of Agronomy and Soil Science, University of New England, 144p. (www.rirdc.gov.au/reports/NPP/UNE-30A.DOC)

Rocha, T. Lebert, A. and Marty-Audouin, C. (1993) Effects of Pretreatments and Drying

Conditions on Drying rate and Colour retention of Basil (Ocimum basilicum). Lebensm.-Wiss. u.-Technol. 26:456-463.

Siddique I, Anis M (2007) Rapid micropropagation of Ocimum basilicum using shoot tip

explants pre-cultured in thidiazuron supplemented liquid medium Biologia Plantarum, 51: 787-790.

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Sifola, M. I., and Barbieri G (2006) Growth, yield and essential oil content of three cultivars of

basil grown under different levels of nitrogen in the field. Scientia Horticulturae, 108: 408-413.

Simon, J.E. (1985) Sweet Basil: A Production Guide. Cooperative extension Service, Purdue University. Bulletin HO-189.

Simon, J.E. (1989) Sweet Basil: A Production Guide. Purdue University Cooperative extension service. HO-189.

Simon, J.E., Chadwick A.F., Craker, L. E (1984). Herbs: An indexed bibliography 19711980.

Archon Books, Hamden. p. 79. Simon, J.E., Morales, M. R., Phippen, W. B., Vieira, R. F., Hao, Z (1999) Basil: A source of

aroma compounds and a popular culinary and ornamental herb. In: J. Janick (ed.), Perspectives on new crops and new uses. ASHS Press, Alexandria, VA. p. 499505

Simon, J.E. and Reiss-Bubenheim, D. (1992) Water stress-induced alterations in essential oil

content and composition of sweet basil. International Journal of Essential Oil Research 4:71-75.

Simon, J.E., Quinn, J., Murray, R.G. (1990a) Basil: a source of essential oils. Advances in New

Crops. Proceedings of the first national symposium on New crops: 484-489. Simon, J.E., Quinn, J., Murray R. G. (1990b). Basil: a source of essential oils.. In: J. Janick and

J.E. Simon (eds.), Advances in new crops. Timber Press, Portland, OR. p. 484489 Telci I, Bayram E, Ylmaz G, Avc B (2006) Variability in essential oil composition of Turkish

basils (Ocimum basilicum L.). Biochemical Systematics and Ecology, 34: 489-497.

3.0 History and origin8.7.2 Harvesting for dried leaf8.7.3 Harvesting for the fresh marketLuvisi A, Materazzi A, Triolo E (2006) Steam and exothermic reactions as alternative techniques to control soil-borne diseases in basil Agron. Sustain. Dev. 26: 201-207.zcan M. M, Ahmet nver A, Uar T, Arslan D (2008) Mineral content of some herbs and herbal teas by infusion and decoction, Food Chemistry, 106: 1120-1127Raimondi, G., Orsini, F., Maggio, A., De Pascale, S., Barbieri, G. (2006) Yield and quality of hydroponically grown sweet basil cultivars. ISHS Acta Horticulturae 723 I International Symposium on the Labiatae: Advances in Production, Biotechnology and...