The commercial cultivation of lac insects is known as lac culture.
Four species of lac insects are
1. Kerria lacca.
2. Tachardia signoret.
3. Tachardiella cockrell.
4. Tachardina cockrell.
Kerria lacca is available in Bangladesh.
Depending on the cultivation procedure, lac insect are two types
1. Kusumi (2 types)
a) Aghani. b) Juhi.
2. Ranginee (2 types)
a) Katki. b) Baishaki.
Ranginee is available in Bangladesh and Kusumi practiced in India.
e) Fig etc.
Lac production Technology
Rearing and harvesting
Raw lac/ Stick lac
Wash in water
Purification by heat and add chemical
Seed lac: Lac insect are borne in plant, specially on the growing point of the plant. The twig which we select for seed lac must be 15-30 cm in length and most of the lac insect remain in egg stage.
Raw lack/Sticky lac: After preparation of seed lac, it will be attached with the
growing point of the host plant. Seed lac is kept in this condition for about two weeks. By this time, the egg will hatch and migrate to the host plant. When the lac insect spread all over the host plant, theseed lac is to removed from the host plant. Lac insects havepiercing sucking type mouthparts.
They will suck cell sap from the host plant by this time they attain nymphal period and secret resin from their formal gland. A layer of resin about 0.6to 1.3 cm built in the host plant. The twig of the host plant with resin is cut and collect lac from them. This is
called raw/stick lac.
Buly lac: From raw lac or stick lac, we get buly lac through scraping and Sieving.
The buly lac is washed with water for several times.
Choury lac: After washing of buly lac, the lac which we get is called choury lac.
Shellac: Afterword purification may be done or may not be done. If purification is
done, heat is applied for boil and then the lac is kept in different shape container giving in different shape. After this process the lac which we obtain is called shellac.
Prospect of Lac culture in Bangladesh
In Bangladesh seed lac are grown two different times. One time is June–July and harvesting period in the month of October–November. Another time is October–November and harvesting in the month of June–July.
To obtain more amount of lac, twig is needed and for this season host plant is to be pruned for two times.
Immediate after pruning, nitrogenous fertilizer have to be applied around the host plant which will make the host plant succulent and this is suitable for lac insect to suck.
Uses of Shellac
▲ It was used in ancient time as wood finish, skin cosmetic and dye for wool and silk.
▲ Lac for dye has been somewhat replaced by the emergence of synthetic dyes though it remains in use, and some juices, carbonated drinks, wine, jam, sauce, and candy are coloured using it.
▲ Lac is used in folk medicine as a hepatoprotective and antiobesity drug.
▲ It is used in violin and other varnish and is soluble in alcohol.
▲ Nail polish, lipstick, gala, Jewellery shop, toys etc are prepared from lac.