🐞 Lac Insect Biology and Lac Culture

Lac culture links insect biology with host-tree ecology and seasonal inoculation management for stable resin production.

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Biology of Kerria lacca

The lac insect, Kerria lacca (Hemiptera: Tachardiidae, formerly Laccifer lacca), is a minute scale insect that secretes a resinous substance called lac from its dermal glands. Lac is the only commercial resin of animal origin. India is the world's largest producer of lac, accounting for over 50% of global production, with Jharkhand, Chhattisgarh, Madhya Pradesh, and West Bengal being the major producing states.

Kerria lacca exhibits marked sexual dimorphism. The female is sedentary, sac-like, and remains fixed to the host plant throughout its life after initial settlement. The male is winged and free-living as an adult. The life cycle spans approximately 6 months and includes the stages of egg, first-instar crawler, second instar, third instar (sexual differentiation occurs), and adult. The female lays 200-500 eggs within her resinous cell, and the first-instar nymphs (crawlers) emerge, disperse along branches, settle at new feeding sites, insert their stylets into the phloem, and begin secreting lac resin around their bodies.

Host Trees

Lac insects feed on the phloem sap of specific host trees. The most important host trees are kusum (Schleichera oleosa), which is considered the best host yielding the highest quality lac; palash (Butea monosperma), the most widely used host in central and eastern India; ber (Ziziphus mauritiana), commonly used as a lac host in Rajasthan and Gujarat; and galwang or ghont (Ziziphus xylopyra). Other hosts include Ficus, Acacia, and Cajanus species. Kusum supports the kusmi strain, while palash and ber support the rangeeni strain of lac insects.

Lac Cultivation Methods

Lac culture is practised in two main systems based on the strain of lac insect and the season of rearing.

Rangeeni Strain

The rangeeni strain is cultivated on palash and ber trees, producing two crops per year: baisakhi (harvested in April-May, inoculated in October-November) and katki (harvested in October-November, inoculated in June-July). The baisakhi crop typically gives higher yield and better quality lac than the katki crop.

Kusmi Strain

The kusmi strain is cultivated on kusum trees and is considered superior due to higher lac yield, better colour, and superior resin quality. It also produces two crops: aghani (harvested in January-February, inoculated in June-July) and jethwi (harvested in June-July, inoculated in January-February).

Inoculation and Harvesting

Lac cultivation begins with inoculation (also called lac infection), in which brood lac sticks carrying mature female insects with developing eggs are tied to fresh host tree branches using cloth strips or jute strings just before crawler emergence. Crawlers emerge, disperse, and settle on the new branches to start a fresh crop cycle. The ratio of brood lac to host branch is maintained at approximately 1:4 by length.

Lac is harvested at the appropriate time either as ari lac (harvested before swarming of the next generation) or phunki lac (harvested after swarming, when crawlers have already emerged and settled elsewhere). Ari lac gives better quality as the resin encrustation is intact, while phunki lac is lighter and of lower grade. Scraped lac (lac removed from sticks and crushed) is then processed further.

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Summary Cheat Sheet

• Kerria lacca is a scale insect producing commercial animal-origin resin.
• Host species and strain selection determine lac quality and yield.
• Crop cycles differ for rangeeni and kusmi strains.
• Timely brood inoculation and harvest stage affect final processing value.

References

1 source • [1]

[1]

Standard lac biology and cultivation references used for lesson preparation.