Silkworm-the Silk spitting insect
By: Dr. M. F. BAQUAL
Silkworm which in Kashmiri is termed as ‘Paithkuim’ and scientifically ‘Bombyx Mori’ is an insect with a difference spitting silk thread which is woven into splendid fabrics.We all know that these fabrics are in turn sold to royal people thus ensuring flow of money from higher class to lower class. Since successful Silkworm rearing and raising of quality and quantity cocoon crop is subservient to precautions our stakeholders take, it becomes mandatory for every individual to ensure that these precautions are taken well and preparation for forthcoming silkworm rearing is done from day one for increased dividends.
On one hand mulberry leaf constitute the only food for silkworms and on the other hand it is reported that one mulberry tree absorb about 4162 kg of carbon dioxide and releases 3064 kg of oxygen each year thus serving the dual purpose of improving economy of stakeholders associated with it and also cleaning our environment.
Role of sericulture industry in amelioration of agrarian economy is tremendous not only in Union Territory of J and K but all over subcontinent as well. The industry in UT has come to therescue of people from times immemorial and history has it that sericulture industry was the unique source of livelihood for the people of this part of globe.Although, with the passage of time there has been a stiff competitionposed to the industry from othersister concerns coupled with availability of more lucrative jobs to the stakeholders, yet silk industry continues to provide livelihood to many due to the efforts taken over by the Department of Sericulture and that of research Institutions.
Non availability of mulberry leaf throughout the year owing to our geographical location and climatic constraints also plays its role for hindering the growth and rendering the venture of silkworm rearing as subsidiary occupation. Be it as it may, mulberry plants continue to be the only source of food for silkworms and the quality and quantity of leafdecides the success and the quantum of the rearing. The role of quality mulberry leaf in sericulture industry is same as the role of air /oxygen in sustenance of human life or for that matter any life form on earth. With a view to enrich mulberry leaf in field that too in the vicinity of rearing zones the Department of Sericulture along with SKUAST-K is supplying quality mulberry plants to rearers year after year throughout the valley in general and that of adopted villages in particular.
Although plantation season is over by now and it is hoped that mulberry planters might have planted mulberry in their orchards or even in fallow or uncultivated land areas, yet it is more important that they should take utmost care in maintaining these by way of irrigation and other intercultural operations. Taking care of plants during establishment phase is of utmost importance. This is to be done for dual purpose as the mulberry plant besides providing food for silkworms also improves the quality of air around and results in sequestration of carbon dioxide. It is reported that one mulberry tree absorb about 4162 kg of carbon dioxide and releases 3064 kg of oxygen each year.
However since the spring rearing season is fast approaching, some important points and precautions / considerations have to be borne in mind for overall success of the rearing and these include:
- Since the success of silkworm rearing to a very larger depends upon the effective disinfection, as such proper disinfection of rearing houses/space and rearing appliances be ensured and in this behalf full cooperation be extended to departmental technocrats who perform disinfection.
- From hatching to its full-grown stage, the silk worms pass through five instars and the worms up to stage two are called young age worms or chawki. Although Department of sericulture is providing chawkie reared to beneficiaries, yet more care needs to be paid to late age worms also by way of maintaining proper hygro-thermic conditions and feeding quality and quantity leaf to worms under the guidance of field functionaries of the department.
- Please ensure that proper spacing is provided to growing worms in proportion to their size and ensure use of bed disinfectants.The late age silkworms do not tolerate high temperature, high humidity and poor ventilation. Hence, the rearing house should have cross ventilation facilities to bring down the room temperature and for removal of vapour and harmful gases generated from large quantities of excreta produced by silkworms.
- Remove the unhealthy larvae, if any and put them into 2% bleaching powder in 0.3% slaked lime solution.Don’t spill the bed refuse on the floor of the rearing room while cleaning the bed. 80% humidity is required for III instar larvae and 70% is required for IV and V instar larvae.The ideal temperature for the late age rearing is 26.
- Ensure good ventilation and dry condition in the rearing house during moulting period and spread the bed gently soon after the worms settle for moult and apply slaked lime powder uniformly over the bed to ensure drying of bed. Avoid high fluctuation of temperature and humidity as well as strong wind and bright light.Resume feeding when 95% of worms come out of moult.
- Wash hands and feet with disinfectant solution before entering in to the rearing house. To begin with, the hands and feet should be washed with alkaline soap and then dipped in disinfectant solution (2.5% Sanitech/ Serichlor in 0.5% slaked lime solution or 2% Bleaching powder in 0.3% slaked lime).
- Pick the diseased worms every day into a basin with lime powder and bleaching powder mixture and dispose off carefully by burning or burying at a distant place. Keep the rearing room clean and well aerated during silkworm rearing.
- Only mature worms be mounted on mountages for spinning cocoons.When the larvae are in spinning stage, the room temperature of 24°C and 60-70 % of relative humidity along with good aeration facility are to be provided.
- Harvest cocoons on 6th day. Remove defective cocoons. After sorting out the defective cocoons grade the cocoons according to the quality. In winter, delay the harvest by one day.
- Store cocoons nicely in gunny bags after complete drying till marketing.
The above precautions need to be followed for increased cocoon crop harvest.
The author is working with SKUASK-K and can be reached at [email protected]