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 * Factors influencing & the estimated loss due to diseases
 * Management of diseases in silkworm rearing
 * Constraints in management of diseases in silkworm rearing

Factors influencing the cause of diseases in silkworm

Diseased silkworm extrudes pathogens into the rearing environment, which form the source for the diseases in the colony. The pathogens are extruded by infected silkworms along with gut juice ( most viral diseases and pebrine disease) and faecal matter (Cytoplasmic polyhedrosis, pebrine and bacterial disease). It also enters into the rearing environment through breakage of fragile integument ( nuclear polyhedrosis, septicemia) or form the body surface ( muscardine and aspergillosis). The dead and the fermented larva. moth also form source of diseases. The wild insects may also form a source of for diseases especially, pebrine and muscardine . In addition, the pathogens are light, easily drift in air and have the ability to remain in active state in rearing environment, for longer period ( three to several years). The pathogens contaminate the mulberry either in mulberry garden or in the rearing house it self and infect silkworms when fed on them.

The silkworm rearing practices followed in sericultural areas are not fool proof for prevention of diseases. Silkworms are reared in rearing cum dwelling houses. Most of these houses are unhygienic, badly ventilated and dark and damp helping in pathogen survival. Silkworm rearing is continuous with little time for disinfection. In fact , most sericulturists do not disinfect the rearing house at all . As the disinfectant Foramline cause discomfort to the residents. Farmers are not self sufficient with rearing appliances , such as rearing trays and chandrike and borrow them leading to contamination. Silkworm bed cleaning practices involving cleaning with hand helps in contamination. Diseased larvae are not picked and even if picked, most farmers do not discard them but rear in separate tray forming a source of infection in the rearing house. The bed refuse are transported in baskets  or gunny bags that are sometimes also used for transportation of mulberry leaves to feed silkworms. While transportation, the bed refuse and diseases silkworms are dropped on the way to litter pit. In some cases the bed refuse is transported directly to the mulberry field which it self gets contaminated. In addition to unhygienic condition, the rearers do not practice rearing and personal hygiene. All these factors lead to prevalence of  diseases in silkworm rearing and crop failure or low yield.


Silkworm diseases are best prevented than cured. The diseases in silkworm are prevented through proper disinfections and rearing hygiene. The disinfections aims at destruction of pathogens in the rearing house and on appliances before the start of the rearing and during rearing of those pathogens that enters into rearing area mainly from the infected larvae. Personal hygiene and rearing hygiene aims to prevention of entry of the pathogen into the rearing house and secondary contamination during rearing. Disinfection of rearing house and appliances eliminates the persistent pathogen. However, the disinfection performed at the beginning of the rearing has no effect on the pathogens that gain entry into the rearing environment during the rearing. The practical approach for the management of disease in silkworm rearing is as follows.

  • Disinfection of silkworm rearing house, surroundings and rearing equipments using physical and chemical methods of disinfection.

  • Rearing early instar silkworms following strict hygienic, congenial environmental and nutritional conditions.

  • Rearing later instar silkworms under optimum rearing area, feeding sufficient quantity and quality mulberry under suitable environmental and hygienic.

  • Prevention of entry of pathogen from outside through meticulously practice of rearing and personnel hygiene during the silkworm rearing.

  • Prevention of spread of silkworm diseases by using silkworm body and rearing seat disinfectant.

In addition to the above, early diagnosis, nutrious mulberry, sufficient ventilation and rearing space adds to the prevention of diseases in silkworm rearing.


The major constraint in silkworm disease management is the need for a disinfectant suitable to the infrastructural facilities available with sericulturists. Formalin was used as a disinfectant in sericulture for the past several hundred years. The unsuitability of the disinfectant under the infrastructural facilities available with sericulturists and its hazardous nature has been responsible for improper disinfection and hygiene. Recently disinfection with bleaching powder solution was introduced as a disinfectant in sericulture. While the disinfectant  eliminated the constraints associated with formalin, its high corrosiveness, unsuitable nature and unsure of quality lead to the similar situation as formalin.

 * Factors influencing & the estimated loss due to diseases
 * Management of diseases in silkworm rearing
 * Constraints in management of diseases in silkworm rearing

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