Botany

The botanical description of davana, as given by Narayana et al. (1978), is as follows: Davana is an annual, erect, branched, aromatic herb, 40-60 cm high and covered with greyish-white tomentose. Leaves are bluish-green in colour, alternate, exstipulate, petiolate, lobed to pinnatisect and covered with greyish-white tomentose. Capitula are peduncled to sessile, axillary or forming lax racemes, simple, heterogamous with yellow florets. Involucre, two or more seriate, with ovate to elliptic-linear, alternating entire bracts, grey-tomentose outside, glabrous and green inside. Outer florets glabrous except for a few cottony hairs, tubular, generally three-lobed, female without pappus; stigma generally two-lobed, rarely three-lobed. Inner

Year

Figure 1 Quantity (x 100 kg) and value (million Rs.) of davana oil exported from India during 1984-85 to 1997-98.

florets also glabrous except for a few cottony hairs, tubular, five-lobbed, bisexual; stamens five with free epipetalous filaments and dithecous, introse, syngenesious anthers; pollen sacs prolonged, tapering; style bifid.

AGRONOMY (INCLUDING DISTILLATION FOR ESSENTIAL OIL)

Davana oil is reported to have been first distilled on an experimental scale from the herb grown near Mysore, as early as in 1921 (Sastry, 1946; Anon., 1947, 1950), at the Government Soap Factory, Bangalore. The commercial distillation and export of davana oil was first taken up at about the same time by Mr. M. Sundara Rao, at M/s. Essenfleur Products Ltd., Mysore, from the davana herb grown in his estate at Hemmanahalli, near Mysore (Sastry, 1946; Menon, 1960). However, according to another report (Anon., 1967), davana oil was first distilled and exported to Europe by Mr. Mavalankar, an Indian perfumer. The report also mentioned that the oil was distilled and exported by The East Indian Sandal Oil Distilleries (Private) Ltd., Kuppam (S. India).

Although Sastry, (1946) Guenther, (1952) and Ranganathan, (1963) briefly described the cultivation and distillation of davana, a detailed account was first given by Gowda and Ramaswamy (1965). Subsequently, Gulati et al. (1967) gave a similar account of cultivation and distillation of davana in the Tarai region in north India. However, the quality of davana oil from this area was not comparable with the quality of oil produced in south India. A farm bulletin describing the cultivation of davana and distillation of its oil was published in 1978 and, subsequently, revised in 1990 (Narayana et al., 1978; Narayana and Dimri, 1990). The above reports appear to be based largely on empirical observations and experience rather than based on data obtained from specifically designed and systematically conducted experiments. A sudden increase in the interest in medicinal and aromatic plants and a preference for plant based rather than synthetic products all over the world during the last decade has resulted in increased scientific activity in this area and davana has also received increased attention. Different agronomic parameters including fertilizer requirement, optimum planting density, planting season etc. for maximizing productivity of davana have been investigated (Table 1). The effect of plant growth regulators like gibberellic acid, cycocel and TIBA (Tri-iodo-benzoic acid), which have been successfully used to increase the yields of several horticultural plants were also studied for their effects on the herb and oil yield of davana; however they were found to be ineffective (Farooqi et al., 1993; Shenoy et al., 1993).

The agronomic practices for davana are summarized as follows after taking into consideration all the published information cited above.

Soil and Season

Davana is cultivated in a very small restricted geographic area in south India. It does not withstand heavy rains and water logging. It grows well in red loamy soils with good drainage and organic matter. The crop can be grown almost throughout the year for ornamental purposes. However, for cultivation of this crop for its essential oil, the season is very important and late October to early November sown crops have been found to give maximum oil yield. Light showers, mild winters with heavy morning dew and no frost in the beginning of the season, and warm and dry weather towards harvest time are believed to contribute to higher oil yields and better quality oil.

Nursery Preparation

Fresh seed obtained from the previous crop should preferably be used as davana seeds are known to lose their viability very quickly. About 1.5 kg of seeds and an area of 500 m2 are required for raising seedlings sufficient for planting an area of one hectare. As the seeds are very small, they are mixed with about 10 kg of fine sand before sowing and are sown by broadcasting the mixture in well prepared nursery beds of generally 3 m2 size. Seeds germinate in three to four days and during this period nursery beds are hand-watered lightly, twice a day. Subsequently, nursery beds are lightly surface irrigated every day. The seedlings reach the transplanting stage after about five weeks.

Table 1 Optimum planting season, plant spacing and nitrogen dose for the cultivation of davana (Artemisia pallens) for its essential oil.

Planting season

Plant spacing (cm.2)

Nitrogen (kg/ha)

Reference

82.5 (Main crop)

Narayana et al. (1982)

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