Environmental factors in silkworm rearing.pptx

12/01/2024 Dr. Kuntamalla Sujatha, S. Bharath & M. Sai Abh
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DEPARTMENT OF SERICULTURE
SUBJECT: Silkworm rearing technology

Environmental
Factors
in
Silkworm Rearing

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INTRODUCTION
• The development of silkworm larvae and cocoon
quality is effected by environmental conditions
such as temperature, humidity, light and air
• As the climatic conditions are not uniform during
rearing period
• The maintenance of environmental conditions
should plays a vital role during the rearing period

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ENVIRONMENTAL FACTORS
• Temperature
• Humidity
• Air
• Light

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TEMPERATURE
• Temperature plays a significant role in silkworm rearing on the
silkworm physiology
• Thus influencing various aspects of their development and
productivity such as growth rate, silk production, moulting ,
disease susceptibility, cocoon quality, hatchability etc..
• Optimal temperature range: 20-28°C
• 1st
Instar-26-28°C
• 2. Instar-26-28°C
• 3rd
Instar-24-26°C
• 4th
Instar-23-24°C
• 5th
Instar-23-24°C

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Effects of high temperature
• Mortality: Prolonged exposure to high temperatures can
lead to silkworm death.
• Reduced growth: High temperatures can slow down
silkworm growth and development.
• Cocoon quality reduction: High temperatures can affect
cocoon quality, leading to weaker or deformed cocoons.

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Effects of low temperature
• Disrupted moulting: Low temperatures can
disrupt the moulting process, leading to
abnormal shedding or failed molting.
• Reduced hatchability: Low temperatures can
affect egg hatchability, leading to reduced
silkworm populations.

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CONTROL MEASURES
To increase room temperature:
• Heaters
• Heat mats
• Reducing ventilation
To decrease room temperature
• Wet gunny curtains
• Fans
• Cooling pads

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Humidity
• The influence of humidity during silkworm rearing has several effects on the
larvae and the rearing process.
• High humidity during chawki stage is beneficial for silkworm growth and
development for the further stages.
• Optimal humidity range: 65%-90%.
Different humidity conditions
1st
instar-85%-90%
2nd
instar-80%-85%
3rd
instar-75%-80%
4th
instar-70%-75%
5th
instar-65%-70%

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Effects of high humidity
• Increases disease susceptibility: High humidity creates an ideal environment
for disease-causing microorganisms, leading to increased disease
susceptibility.
• Mould and fungus growth: High humidity promotes mold and fungus growth,
which can infect silkworms and contaminate cocoons.
• Larval stress and mortality: High humidity can cause larval stress, leading to
increased mortality rate.

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Effects of low humidity
• Reduces fecundity and fertility: Low humidity can lead to low egg
production and fertility in silkworms.
• Increases incidence of unfertilized eggs: Low humidity can lead
to an increase in unfertilized eggs.
• Deleterious effect on larval development: Low humidity can
affect larval development, leading to low weight and survival rate.

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Control measures
To increase room humidity
• Humidifiers
• Water spray
• Damp sponges
To decrease room humidity
• Heaters
• Charcoal stoves
• Increase air movement

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Air
• The air will plays a crucial role during the rearing of silkworms .
• The air helps to remove excess moisture, maintains optimal
temperature, removes CO2 and stale air, reduces disease risk etc…..
• Cross ventilation is recommended to keep the temperature and
humidity at optimal levels.
• It is essential to maintain optimal air movement levels 0.5-1.5
meters per second during silkworm rearing.

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Effects of high air movement
• Reduces feeding: Strong airflow can disrupt feeding behavior, leading
to reduced food intake and growth.
• Increases mortality: Prolonged exposure to high air movement can
lead to increased mortality rates.
• Reduces cocoon quality: Strong airflow can reduce cocoon quality,
making them less suitable for silk production.

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Effects of low air movement
• Reduces oxygen supply: Insufficient air movement can lead to
reduced oxygen supply, causing stress and discomfort for
silkworms.
• Impaired moulting : Stagnant air can disrupt the molting
process, leading to abnormal molting and development.
• Increases humidity: Stagnant air can lead to increased
humidity, which can promote mold and fungus growth,
damaging cocoons and silkworms.

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Light
-
• The embryonic development followed by hatching is influenced
by light.
• The light influences the growth and development , moUlting or
shedding , hormone regulation, photo periodism etc….
• The optimal light conditions for silkworm rearing are:
i. Intensity: 100-200 lux (equivalent to indirect natural light)
ii. Duration: 12-14 hours of light, 10-12 hours of darkness.

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Effects of less light
• Reduces growth rate: Silkworms grow slower and may be
smaller in size.
• Poor feeding behavior: Silkworms may have reduced
appetite and feeding activity.
• Delayed development: Developmental stages may be
delayed or prolonged.

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Effects of more light
• Reduced disease susceptibility: Stronger immune
system reduces disease susceptibility.
• Reduced growth and development: Excess of light
will effects upon the growth and development of
silkworms

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Conclusion
• Maintaining optimal environmental conditions is essential for
successful silkworm rearing and high-quality silk production.
• Regular monitoring and adjustment of temperature,
humidity, ventilation, and cleanliness are key factors in
ensuring the health and productivity of silkworms.
• By following these guidelines, silkworm farmers can create a
conducive environment for the growth and development of
silkworms, leading to a successful silk production cycle.

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Thank You
ACKNOWLEDGE FROM INTERNET

Environmental factors in silkworm rearing.pptx

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