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 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.

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.

0
0.5
1
1.5
2
2.5
3
3.5
4
Red Powdery Red Non-
powdery
Green
powdery
Green Non-
powdery
Cocoon Wt (gm) PupalWt (gm) ShellWt (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 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

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 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 CO2 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.

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 Icfai
Journal 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
Das
Arunodoi Junior College, Tangla
Ms. Archana Das
Asst. Professor, Tangla College
Tangla
Mr. Mintu Pathak
Asst. Professor, Tangla College
Tangla

Growth And Economic Parameters Of Eri Silkworm Rearing

Growth And Economic Parameters Of Eri Silkworm Rearing

More Related Content

What's hot

Viewers also liked

Similar to Growth And Economic Parameters Of Eri Silkworm Rearing

Recently uploaded

Growth And Economic Parameters Of Eri Silkworm Rearing