Any agro-based practice lies directly with Uganda’s greatest economic booster and backbone, agriculture.
Sericulture has overtime, been one of the quite silently practiced agro-based trades in the country since the ’90s, and is a profitable business given the fact that each stage of the sericulture value chain, pays a farmer in bounty.
Sericulture, also called silk farming, is the art and, or, science of producing silk fibres through raising caterpillars (larvae), particularly the domesticated silkworm, Bombyx mori.
Silkworms are very special and delicate organisms, which need tender care handling and management right from the egg stage to the pupa stage (cocoon)
Here is a simple step-to-step guide on how to properly manage a Seri-business along the sericulture value chain, right from the cultivation of mulberry to production of the final product, silk fabrics.
An average sericulture rearing practice is started on at least an acre of cultivated mulberry
Mulberry is vital for silkworm rearing as silkworms feed on mulberry leaves throughout their life time to the final stage when they spin to cocoons.
Mulberry plant, locally known as ‘Ekenene’ (luganda name), is a crop that grows so well and can be cultivated in Uganda’s favourable climate and great soils.
Mulberry being a perennial crop is easily maintainable, as it lasts close to 15-20 years in a garden, and maintenance is as easy as pruning and it is from this pruning that more cuttings can be generated to set up another garden or for sale. The cuttings are affordable, currently sold at 25shs each.
The key activities in mulberry production include; Ploughing of the garden, harrowing, acquiring of planting materials (cuttings), planting of the cuttings (done in a slightly slanting posture, leaving 2 buds above the ground), weeding and the chemicals (spraying the plants with pesticides and fungicides to disinfect them from pests and diseases that could possibly lower the product output in the end).
Establishment of a Mulberry garden for Mulberry production moves hand in hand with construction of a rearing house for Cocoon production.
This is because once Mulberry leaves mature, they act as food for the growing silkworms to mature into Cocoons, if fed and monitored regularly.
The leaves are highly rich in protein content and the healthier the leaves are, the more healthier the silkworms, too, since the entire life cycle depends in feeding off these leaves,
Mulberry leaves are also multipurpose as they are highly medicinal, can be used as feed by both humans and domestic animals, plus their fruits can be consumed as snacks and, or for wine production.
Mulberry leaves are major economic components in sericulture as their quality and quantity per unit area, have a direct impact on cocoon quality and quantity too. Therefore, farmers have to closely monitor their mulberry gardens to ensure healthy production so as to have quality cocoon outputs at the end of the day.
As the mulberry plantings mature up, one has to move to the next stage of the sericulture value chain, which is, setting up a grainage, for silkworm egg production and a silkworm rearing house.
Grainage and Rearing house construction and tips of maintenance
A grainage is a silkworm egg production house, where silkworm eggs are incubated and hatched before being transferred to the official rearing house beds.
Construction of a simple temporary rearing house, which is well shielded from wind, gases and fumes or dusty condition, can be the trick for a saving expenses and evolvement can come with better profits.
Construction of an average permanent rearing house in Uganda is approximately 13 million shillings – a farmer can choose a cheaper temporary structure too, it gives off the same results at the end of the day.
It has to be equipped with the following equipment: Sprayer, room heater, plastic basins, rearing racks, collecting bags, montage, nylon nets, buckets and a hand thermometer to take note of temperature regulation in the house, so as not to risk losing the silkworms.
A good rearing house should be well regulated, temperature and humidity wise, properly cleaned and spaced because all these affect silkworm production strongly.
The conditions of the rearing house should be favourable enough, having the temperatures ranging between 22•C to 28•C and humidity at 70-80%. These numbers of regulation vary with the stages of growth from the 1st to the 4th Instars.
Hygiene in a rearing house should be the priority, disinfection for a clean environment and to avoid infections among silkworms too.
Silkworms have to be reared in very hygienic environments, free from dirt, perfumes, chemicals, dumpiness and diseases. This is to avoid deaths among worms which could lead to losses in production at the end of the day.
While rearing, feeds (mulberry leaves) have to be healthy-looking, and free of any moisture as silkworms do not like feeding on dump mulberry,
Silkworm rearing and in-house maintenance
Silkworm rearing is the most vital stage in production, here, the farmer has to inject lots efforts into the feeding, management and hygiene maintenance among the silkworms, right from their hatching stages to the larva stages, before cocooning starts.
Farmers sometimes rear their own butterflies to lay silkworm eggs but this could lead to uneven cocoon weights, so preferably, buying uniformly weighed silkworms would result to a uniformly weighing number of cocoons too.
Proper management of the mulberry crops and cocoon rearing houses are very profitable to a determined farmer generally. It is a life changing step in farming.
This will not only ensure that one has healthy silkworms, but also a great cocoon output at the end of the day, the trick lies in how often one feeds the worms and on how healthy the mulberry leaves being given to the silkworms as feeds, are.
Silkworms are quite delicate and require utmost attention right from feeding to environments around then, as they react to any unfavourable conditions, like heat exposure, high temperature, perfumes, fumes and gases, chemicals and disinfected hands.
Silkworms are fed on mulberry leaves that are fresh, healthy, and highly rich in nutrients, mostly in proteins, for it keeps their bodies healthy, for healthier cocoons and good thread at the end of the day.
These leaves should be dry with no water drips or moisture, mulberry leaves, are grown in varied climatic conditions, ranging from temperate to tropical. The leaves are kept free from moisture as the worms do not feed on wet leaves, same reason moisture is avoided on the rearing beds by application of lime, to keep the worms free from moisture.
Feeding evolves according to the stages of growth among silkworms, the young silkworms are fed on fresh, finely chopped young, healthy mulberry leaves, picked from the first 3 shoots, up of a mulberry plant, and as the worms grow, they can be served whole leaves or even branches of leaves. This is because they are old enough and consume quite much at the older stages.
Utmost hygiene should be a priority and maintained in the silkworm rearing rooms, disinfection being a key element.
This comes right from maintenance of a clean environment around the rearing house and the rearing beds through disinfection plus washing of hands with water, which is pre-disinfected with a bleaching reagent, before touching silkworm feeds or silkworms themselves.
Disinfection of the silkworm rearing house should be done at least twice before the rearing cycle, one after rearing and the other before rearing, this is to ensure management of any infections or diseases that may have been in the rearing house or rearing beds, while hygiene carries on, throughout the entire cycle.
After ensuring a clean environment, one should watch out for the temperature ranges with in the rearing house too.
The favourable temperature range for the rearing house is 22-28 degrees Celcius, while for best productivity, the numbers should be within 23-28 degrees Celcius. Any slight alteration beyond or below these numbers are capable of greatly affecting the health of the silkworm, hence causing low productivity.
Temperature regulation is very vital as exposure to unfavourably too high or too low temperatures, becomes a disaster to the worms.
As silkworms grow, they are dried into cocoons under carefully monitored temperatures in rearing houses, or else risk the eggs hatching.
Cocoon and silk fabric Production
Cocoon production is among the final stages in production and it involves rearing of silkworm eggs right from the egg stage to the larva and when silkworms spin a white (or any other natural pigmentation), around itself, it is called a Cocoon.
Cocoons are the pupal stage of the silkworm life cycle, just as it is in the life cycle of a butterfly or a moth.
When a silkworm leaves the larva stages (stages 3 and 4), it proceeds into a 5th stage, where it starts spinning a ‘home’ for its pupal self, a white protein fibre (or any natural pigment like yellow, red, purple, among others), which acts as a protective shield for its pupa.
Cocoon production stages are aided by the use of spinning frames or locally by the use of dry banana leaves. Spinning frames, however, ensure uniformly healthy cocoon sizes. The frames exist in plastic and wooden forms.
Cocoons have to be handled in a way that, they dry in time or else a farmer risks them turn into butterflies. The time ranges from 0-28 days.
They are harvested from cocoon frames, treated with aluminium sulphide, dried under high temperature conditions, which kills the pupa inside the cocoon and there after a silk thread in extracted. Cocoon drying can be by sun drying or use of a cocoon drier.
The standard weight of cocoons is 4gms when dry, and it is determined by the size of the silkworms
After cocoons are harvested, cocoon drying is done under high temperatures with and aid of a cocoon drier or locally by exposure to direct sunshine (sun drying), then reeling and re-reeling processes set in and thereafter, the extracted raw silk thread is processed into fine silk, which can be made into cloth to produce various products like Gomesis (an African traditional dress), neck ties, shirts, dresses, night gowns, bags, handheld fans and bed sheets, among others.
The above stages are a simple guide through the sericulture value chain, and an average farmer can earn right from first stage of mulberry cultivation by selling cuttings to the cocooning stage and lastly the final stage of fabric production.
The Commercialization of Sericulture Technologies and Innovations project in Uganda, is implemented by the Tropical Institute of Development Innovations (TRIDI), under the supervision of Clet Wandui Masiga, PhD, the project Principal Investigator.
Story Feature Compiled by Mercy Scarlet Kigai, P.R.O, TRIDI.