Lac is the scarlet resinous secretion of a number of species of insects, namely some of the species of the genera Metatachardia, Laccifer, Tachordiella, Austrotacharidia, Afrotachardina, and Tachardina of the superfamily Coccoidea, of which the most commonly cultivated species is Kerria lacca.
The above-mentioned families are some of the 28 families of scale insects and mealybugs comprising a large group of about 8,000 described species of plant sucking insects, a few of which produce similar natural products (e.g., cochineal and crimson). Thousands of these tiny insects colonize branches of suitable host trees and secrete the resinous pigment. The coated branches of the host trees are cut and harvested as sticklac.
The harvested sticklac is crushed and sieved to remove impurities. The sieved material is then repeatedly washed to remove insect parts and other soluble material. The resulting product is known as seedlac. The prefix seed refers to its pellet shape. Seedlac which still contains 3-5% impurities is processed into shellac by heat treatment or solvent extraction.
The leading producer of Lac is Jharkhand, followed by the Chhattisgarh, West Bengal, and Maharashtra states of India. Lac production is also found in Bangladesh, Myanmar, Thailand, Laos, Vietnam, parts of China, and Mexico.
Kerria lacca can be cultivated on either cultivated or wild host trees.
- In India the most common host trees are
- In Thailand the most common host trees are
- In China the common host trees include
- In Mexico
The use of lac dye goes back to ancient times. It has been used in India as a skin cosmetic and dye for wool and silk. In China it is a traditional dye for leather goods. The use of lac for dye has been supplanted by synthetic dyes. It is used in medicine as a hepatoprotective and anti-obesity drug. It is used in violin and other varnish and is soluble in alcohol. This type of lac was used in the finishing of 18th-century fowling guns in the United States.
- Kerria lacca - the true lac scale.
- Paratachardina decorella - the rosette lac scale.
- Paratachardina pseudolobata - the lobate lac scale.
- Carmine (E120) - Another pigment extracted from an insect.
- Lacquer - A product that was at one time made from lac, but in modern common usage now refers to a separate product with similar properties.
- Shellac - A protective coating.
- Iwasa, S, 1997. Schleichera oleosa (Lour.) Oken. In Faridah Hanum, I. & van der Maesen, L.J.G. (Eds.): Plant Resources of South-East Asia No. 11. Auxiliary Plants. Prosea Foundation, Bogor, Indonesia. pp. 227-229.