Growth And Economic Parameters Of Eri Silkworm Rearing

1. GROWTH AND ECONOMIC PARAMETERS OF ERI SILKWORM REARING FED ON DIFFERENT VARIETIES OF CASTOR LEAVES A Case study of Bhergaon Sub-Division, Udalguri , BTAD, Assam

2. Introduction Eri silkworm, Samia ricini (Donovan) is a multivoltine insect and largely reared by the farmers of North Eastern India, particularly in Assam . However, Kesseru is considered as another major perennial food plant. Besides these two, eri silkworm being polyphagous feeds on several alternative host plants, viz., Tapioca ( Manihot esculanta ), Kesseru (Ailanthus excelsa ), Barpat (A. grandis ), Gulancha ( Plumeria acutifolia ), Gamari ( Gmelina arborea ) and many more. Eri silkworm feeds primarily on Castor leaves ( Ricinus communis Linn ) . Castor plant belongs to the family Euphorbiaceae and is a primary food plant of eri silkworm.

3. The food provided to silkworms during their rearing affects larval growth, survival rate, cocoon parameters and silk quality. In the biodiversity of Bhergaon Sub-division in Udalguri , Assam four different varieties of castor plants are available and the reares use all the four varieties of castor leaves randomly without considering the growth and economic parameters of eri silk rearing. These varieties are: a) Red powdery variety b) Green powdery variety c) Red non-powdery variety d) Green non-powdery variety .

4. Red and green varieties of castor

5. i ) To find out the suitable variety of castor plant in the biodiversity of Bhergaon Sub-division for eri silk rearing. ii) To find out the castor variety as the best in terms of larval duration, larval weight, larval growth and pupal duration as growth parameters of eri silkworm rearing. iii) To find out the castor variety as the best in terms of cocoon weight, shell weight, shell ratio and yield/400 larvae as economic parameters of eri silkworm. T he objective of this present study has been:

6. Study area The present study has been conducted at Tangla , Ward No 4 of Bhergaon Sub-division, Udalguri district. Tangla is a busy town in Udalguri district situated in 26.6571 N and 91.9125 E coordinates. The average annual temperature of Tangla is 25.4 C and the average annual rainfall is 184 cm. The relative humidity of Tangla in average is 81%.

7. Bhergaon sub-division in Udalguri district of Assam is situated in North-Eastern India. Its geographical location is 26° 34' 28.53" N 91° 58' 32.42"E. The average attitude is 37 meters. The climate is humid and congenial, while the relative humidity is around 82%. The annual rainfall is 1850 mm (approx). Bhergaon Sub-Division, Udalguri

8. Field Work Details The eggs of eri silkworm were collected from Sericulture Firm (Central), Mangaldoi and the eggs were disinfected with 2% formalin The eggs were then kept for hatching. When the larvae hatched, they were fed on tender castor leaves in a controlled method Experiments were conducted from the second moulting to harvesting of cocoons A total of 400 silkworms were maintained separately in 4 wooden trays and the tender leaves of castor were fed four times a day until the larvae reached 3 rd instar stage. Semi tender leaves were fed in the 4 th and 5 th instar stages

9. The rearing performance of Eri silkworm larvae in each tray was assessed by the following parameters: Hatching Larval weight (gm) Larval duration (day) Yield/400 larvae (by number) Yield/400 larvae (by weight) Cocoon weight (gm) Shell weight (gm) Shell ratio (%) Pupal period (day) and Pupal weight (gm).

10. i ) In the first bamboo tray the larvae were fed strictly on Red powdery variety of castor leaves till cocoon formation. ii) In the second tray the larvae were fed on Red non-powdery variety of castor leaves. iii) The larvae of the third tray were supplied the Green powdery variety of castor leaves. iv) In the fourth bamboo tray the larvae were fed on Green non-powdery variety of castor leaves till cocoon formation. The larvae were transferred to bamboo trays for proper growth and observation. The experiment was conducted with 100 larvae per bamboo tray in each replication as follows:

11. Analysis of the study The larval weight of different Eri silkworm reared in the different trays ranged from 6.45 gm to 8.50 gm during 2013 monsoon. The highest larval weight of 8.50 gm was observed in the larvae reared in the tray with Red powdery castor leaves while the lowest larval weight of 6.45 gm was observed in the tray reared with Green non-powdery castor leaves.

12. Rearing parameters Red powdery Red Non-powdery Green powdery Green Non-powdery Larval duration (d) 24 24.5 26 27 Larval weight (gm) 8.5 8 7.2 6.45 Yield/400 larvae 97 ± 2 85 ± 2 80 ± 2 78 ± 2 Cocoon weight (g) 3.59 3.52 3.31 3.18 Shell weight (gm) 0.59 0.55 0.55 0.48 Shell ratio (%) 16.5 16.1 15.75 15.15 Pupal duration (d) 10.24 10.5 10.75 11.0 Pupal weight (gm) 1.99 1.90 1.75 1.72 Table: 1. Rearing performance of eri silkworm, Samia ricini (Donovan) fed with different castor leaves in 2013 monsoon rearing at Tangla .

13. Larval Duration Red powdery variety: 24 days Red non-powdery variety: 24.5 days Green powdery variety: 26 days. Green non-powdery variety: 27 days Larval Weight Red powdery variety: 8.5 gm Red non-powdery variety: 8.0 gm Green powdery variety: 7.2 gm Green non-powdery variety: 6.45 gm Yield/400 Larvae Red powdery variety: 97 ± 2 Red non-powdery variety: 85 ± 2 Green powdery variety: 80 ± 2 Green non-powdery variety: 78 ± 2 Cocoon Weight Red powdery variety: 3.59 gm Red non-powdery variety: 3.52 gm Green powdery variety: 3.31 gm Green non-powdery variety: 3.18 gm

14. Shell Weight Red powdery variety: 0.59 gm Red non-powdery variety: 0.55 gm Green powdery variety: 0.55gm Green non-powdery variety: 0.48 gm Shell Ratio (%) Red powdery variety: 16.50% Red non-powdery variety: 16.10% Green powdery variety: 15.75% Green non-powdery variety: 15.15% Pupal Duration Red powdery variety: 10.24 days Red non-powdery variety: 10.50 days Green powdery variety: 10.75 days Green non-powdery variety: 11.0 days Pupal Weight Red powdery variety: 1.99 gm Red non-powdery variety: 1.90 gm Green powdery variety: 1.75 gm Green non-powdery variety: 1.72 gm

15. Leaf varieties Red Powdery Red Non-powdery Green Powdery Green Non-powdery Cocoon Weight (gm) 3.59 3.52 3.31 3.18 Pupal Weight (gm) 1.99 1.90 1.75 1.70 Shell Weight (gm) 0.59 0.55 0.55 0.48 Table: 2. Cocoon weight, P upal weight and Shell weight of E ri silkworm in gram.

16. A comparision of cocoon weight, pupal weight and shell weight of eri silkworm fed with different varieties of castor leaves from the data of Table:2

17. Suggestion The eri silkworm rearers should provide only Red powdery variety of castor leaves as the food plant to the growing larvae instead of depending much on the secondary or tertiary food plants . Since, the Red powdery variety of castor leaves is the best among all the four varieties, eri silk rearers should cultivate this breed of castor plant in their farms to overcome the scarcity of primary food plants. Both government and non-government sericulture farms should do the necessary arrangement for the large scale plantation of Red powdery variety of castor plants. Government should come forward with some specific schemes to help the common eri silkworm rearers by providing them loans and other facilities to cultivate Red powdery variety of castor plants in their own farms

18. The government sericulture department itself or with the help of some NGOs should organize training and awareness programmes to provide necessary instructions to the common eri silkworm rearers about the importance and effect of food plants on the growth of eri silkworm and its economic parameters of eri silkworm rearing . The present work has been conducted strictly in the climatic and geographical conditions of Bhergaon Sub-division for the monsoon breed of eri silkworm. In different climatic and geographical conditions, the effect of food plants on the growth and economic parameters may vary. So, government and sericulture departments should take necessary step to invite experts to work in this field and find out if effect of food plants on the growth and economic parameters of eri silkworm rearing is dependent on the varied climatic and geographical conditions of a locality.

19. Conclusion In Bhergaon Sub-division of Udalguri district, ericulture is an age-old traditional cottage industry. Next to agriculture, ericulture is the major agro-based industry generating large number of employment in the rural areas of Assam including the Bhergaon sub-division of Udlguri with minimum investment cost. It plays a very vital role in the socio-economic development of the weaker section of the rural population especially among the the tribal community in this part of BTAD especially during their off-agricultural season. It is needless to mention that any kind of plantation is always helpful in maintaining the CO 2 level of atmosphere and has effective role in reducing global warming. Castor plantation can help the eri silkworm rearers not only to overcome the scarcity of primary host plants, but also can be a source of wealth as it can yield precious castor oil. Therefore, the eri rearers of Bhergaon Sub-division should cultivate and use the Red powdery variety of castor leaves as the food plants for eri silkworms rather than the green powdery or green non-powdery varieties of castor leaves available in the biodiversity of this locality.

20. Reference Gomma , A. Ahmed. (1972) , Biological study on the eri silkworm, Attacus ricini Boisd . Indian J. Seric (1): 81-87 Hazarika , U., Borah, A. & Chakravorty , R. 2005 (Physiological and biochemical response of castor ( Ricinus communis ) to application of NPK and their correlation with economic parameters of eri silkworm, Samia ricini (Donovan) in: Proceeding of 20 th Congress of international sericulture commission vol II, sec 3 Non mulberry silkworms, 2005, Bangalore, India 94-98 Sarkar , D.C. 1988, ( Ericulture in India, Central Silk Board, Grafo Printers Bangalore, page 1-4 Dookia , B.R.(1980): Varied silk ratios in Cocoons of Eri silkworm ( Philosamia ricini Hutt.) reared on different castor varieties in Rajasthan. Indian J. Seric 19(1); 38-40 Dookia B.R. (1986): Biological studies of the Eri silkworm, ( Philosamia ricini Hutt.) on four castor varieties in semi arid climate of Rajasthan. Seric 2(3); 33-34 Dutta , L.C. and Kalita D.N. (1997): Food consumption and utilization by the larvae of Eri silkworm ( Philosamia ricini Hutt.) on diffent food plants. J. Appl. Zool. Res 8(2); 143-144 Slansky , F. Jr. and scriber, J. M. (1985): Food consumption and utilization in Comprehensive Insect Physiology, Biochemistry and Pharmacology. Eds. Kerkut , G.A. and Gillbert , L.I. Vol. IV, Pergamon Press, Oxford: pp 87-160 Baruah , M (2012): Studies on Larval Weight and Shell Ratio of Eri Silkworm ( Philosamia ricini ) on Castor, Kesseru and Treated Kesseru by Foliar Spray. IJCAES SPECIAL ISSUE ON BASIC, APPLIED & SOCIAL SCIENCES, VOLUME II, JULY 2012 C. Manjunatha Naik   ,  C. Murthy   (2011): Evaluation of New Host plant species for ericulture , International Journal of Plant Protection Das, M &De Sr , Utpal Kumar (2007): Village-Based Informal Ericulture and EndiTextiles in Assam: An Economic Inquiry. The Icfai Journal of EntrepreneurshipDevelopment , Vol. 4, No. 3, pp. 8-29, September 2007

21. Website http://www.krishisewa.com/cms/articles/productiontechnology/251erihostcastor.html http://www.scienceandnature.org/IJSN_V1(2)_D2010/IJSN_V1(2)_12.pdf http://www.ijlbpr.com/jlbpradmin/upload/ijlbpr_51835fbbec469.pdf http://cmerti.res.in/faq.html http://www.slideshare.net/prarkl/bioprop

22. Presented by: Mr. Pranabjyoti Das Arunodoi Junior College, Tangla Ms. Archana Das Asst. Professor, Tangla College Tangla Mr. Mintu Pathak Asst. Professor, Tangla College Tangla