2. INTRODUCTION
Flacherie is a bacterial disease of silkworms.
This disease affects the alimentary canal of silkworms.
The following are the different types of flacherie:
1. Clear head or Clear trunk disease: Depends on whether the anterior or posterior
part of the alimentary canal is free of mulberry leaves.
2. Shrinking Disease: The larva loses appetite and becomes shrunken in size.
3. Sotto Disease: Healthy larva suddenly loses appetite and shows signs of pain and
dies.
4. Faecal Chain Disease: The larva excretes soft , sticky faeces that clings to each other
like a chain of beads.
5. Softening Disease: The cadaver of the affected worms becomes tender and soft.
3. CAUSES
This disease is considered to be caused due to the multiplication of bacteria in
the alimentary canal which has become weakened due to bad environmental
conditions.
Environmental Factors that induce Flacherie:
1. Unhygienic environment in rearing room
2. Provision of unhealthy leaves
3. Tender leaves to mature worms and coarse leaves to larvae
4. Starvation for a long time
5. Unfavourable temperature and humidity
4. Various pathogens are known to cause
this disease. They are: Staphylococcus
aureus , Micrococcus Lardarius ,
Escherichia coli , Bacillus bombycids etc.
29 species of bacteria have been isolated
from diseased worms.
However the bacteria causing flacherie
can be classified into three groups:
1. Those that affect only the alimentary
canal
2. Those that affect both alimentary canal
and haemolymph
3. Those that affect only haemolymph
5. SYMPTOMS
Loss of appetite
Sluggishness
Retardation of growth
Softening and inelasticity of the skin
Diarrhoea
Vomiting
Yellow digestive juice turns black in colour
Cylindrical cells and goblet cells are affected
6. TRANSMISISON AND CONTROL
MEASURES
This disease is transmitted through oral means and due to bad rearing
conditions.
The following are the control measures:
1. Provision of optimum environmental conditions
2. Provision of quality leaves during rearing
3. Avoiding unhealthy larvae
4. Providing optimum temperature and humidity
5. Disinfection of rearing houses and appliances with 2% Formalin
