Growth And Economic Parameters Of Eri Silkworm Rearing

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

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.

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.

RED AND GREEN VARIETIES OF CASTOR

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.

The objective of this present study has been:

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

26.65710

N and 91.91250

E

coordinates. The average

annual temperature of Tangla

is 25.40

C and the average

annual rainfall is 184 cm. The

relative humidity of Tangla in

average is 81%.

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

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 3rd instar stage. Semi tender leaves were fed in

the 4th and 5th instar stages

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).

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:

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.

Rearing

parameters

Red powdery Red Non-powdery

Green powdery GreenNon-powdery

Larval

duration (d)24 24.5 26 27

Larval weight

(gm)8.5 8 7.2 6.45

Yield/400

larvae97 ± 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.

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





Shell Weight



Green powdery variety: 0.55gm


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





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, Pupal weight and Shell weight of Eri silkworm in gram.

00.5

1

1.52

2.53

3.54

Red Powdery Red Non-powdery

Greenpowdery

Green Non-powdery

Cocoon Wt (gm) Pupal Wt (gm) Shell Wt (gm)

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

Suggestion

The eri silkworm rearers should provide only Red powdery variety of castorleaves 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 fourvarieties, eri silk rearers should cultivate this breed of castor plant in theirfarms to overcome the scarcity of primary food plants.

Both government and non-government sericulture farms should do thenecessary arrangement for the large scale plantation of Red powdery varietyof castor plants.

Government should come forward with some specific schemes to help thecommon eri silkworm rearers by providing them loans and other facilities tocultivate Red powdery variety of castor plants in their own farms

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.

In Bhergaon Sub-division of Udalguri district, ericulture is an age-old traditionalcottage industry. Next to agriculture, ericulture is the major agro-based industrygenerating large number of employment in the rural areas of Assam including theBhergaon sub-division of Udlguri with minimum investment cost. It plays a very vitalrole in the socio-economic development of the weaker section of the ruralpopulation especially among the the tribal community in this part of BTAD especiallyduring their off-agricultural season.

It is needless to mention that any kind of plantation is always helpful in maintainingthe CO2 level of atmosphere and has effective role in reducing global warming. Castorplantation can help the eri silkworm rearers not only to overcome the scarcity ofprimary host plants, but also can be a source of wealth as it can yield precious castoroil. Therefore, the eri rearers of Bhergaon Sub-division should cultivate and use theRed powdery variety of castor leaves as the food plants for eri silkworms rather thanthe green powdery or green non-powdery varieties of castor leaves available in thebiodiversity of this locality.

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 20th 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 IcfaiJournal of EntrepreneurshipDevelopment, Vol. 4, No. 3, pp. 8-29, September 2007

•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

Presented by:

Mr. Pranabjyoti

DasArunodoi Junior College, Tangla

Ms. Archana DasAsst. Professor, Tangla College

Tangla

Mr. Mintu PathakAsst. Professor, Tangla College

Tangla

Growth And Economic Parameters Of Eri Silkworm Rearing

Education