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 Sericulture - Muga Food Plants Cultivation  

1. VARIETIES

Muga food plants thrive well in sub-tropical areas. The main food plants are Som (Machilus bombycina) and Saulu (Litsaea polyantha) though some other food plants like Mejankari (Litsaea citrala), Digloti (Lisaea salicifolia), choa (magnolia sphenocarpa), Bhumloti (Symploces gradifflora), etc., are also there.

Some plants grow up to an altitude of about 600 metres while Sualu up to 1000 metres above  sea level. Suitable Som and Sualu plants are selected taking into consideration their growth, rearing results, disease resistance, etc. The leaves of som plants have different taste. They are to be selected considering of their growth, leaf-yield, shape and size of the leaf, its taste and odour. Naharpatiya, and Sompatiya with sweet taste are said to be the best. Selection of Som plants should be done in Government Farms on the merit of their performance. There is only one type of Sualu plant. However three varieties of it may be differentiated according to the size shape and colour of leaves. Four varieties of Mejankari found according to the size, shape and colour of their leaves. Digloti is also found in four varieties-two from size and two according t colour of its leaves.

All the muga food plants are perennial and as such the cost in maintenance of the plantation is less. Som trees are preferred by rearers due to their long life span and more resistance to stem borer’s attack.

Plants growth is controlled be several environmental factors like solar radiation, temperature, humidity, rainfall, wind etc. One should have the basic knowledge of environment, climatic zones, distribution of various plants, and ecology and plant physiology for a better plantation.

2. PREPARATION OF SOIL

Before plantation of various Muga food plants, a suitable site in the Muga growing areas should be selected. Soil should preferably be sandy-loam. Information regarding soil conditions, rainfall, temperature and humidity sub-soil water level, etc., of the place should be collected. After selection of the site reclamation works such as, jungle cutting and burning, hoeing, ploughing, harrowing, leveling and terracing in sloppy land, etc., should be done during November to February till the land is become fit for plantation. The pits are to be dug out well ahead of plantation during December to February in a systematic way. The size and the depth of the pits may vary (usually 30 centimetres diameter and 30 centimetres deep) according to the root system of the seedlings/saplings/clones. Pits should be filled with cowdung, compost, dug out top soil and insechicide in required proportion after thoroughly mixing them.

3. PROPAGATION

Muga food plants can be propagated from seeds, stem cutting and air layering etc. Proper selection of food plants with all requisite qualities before prorogation must be done for harvesting successful crops.

Nursery is a must for propagation. Nursery beds are to be prepared during January-February and manured properly. Raised nursery beds are more suitable for many reasons. Sheds should be provided during winter especially in cooler region. Regular watering, weeding and loosening of soil from time to time are to be done whenever necessary. Water may be spayed in the nursery beds before a few days of planting the cutting to keep them wet. Seedlings are to be trained by removing apical buds in the nursery when they grow about 30 cm high.

It is very common to propagate Muga food plants from seeds (sexual) muga food plants are very slow growers and take about 4-5 years to be ready for rearing. So, it is not advisable to propagate from seeds for large scale plantation. It is also difficult to maintain the required qualities of the plants due to cross pollination. The viability of seeds in the case of most of the muga food plants is very short. Therefore fully matured seeds (available during June-July) are to be collected and sown in the nursery beds as early as possible with a spacing of 15cm x 15cm at a depth of about 2cm. Seeds sink in water are considered to be healthy and viable and germinate after 4 weeks of sowing in normal conditions. Thinning is necessary to keep the spacing of Seedlings in the nursery bed at about 30 centimeters. This will facilitate future working and transplantation. Seedlings may be raised in polythene bags containing a mixture of soil, sand and cow dung. (I:I:I). Before putting the seeds in polythene bags, they are to be kept on moist bed under shed and covered with wet gunny bags to keep the moisture and to induce early germination.

3. 1 Stem Cutting: Vegetative (a sexual) propagation will be quick to grow and plants wou’d be dwarfs with abundant branches and leaves. It inherits all the actual characteristics of the parents.

Propagation from stem cuttings is the easiest most convenient and economic method of vegetative propagation. The ability of plant cuttings to grow roots varies from species. Rooting may be induced through manipulative treatment by altering the physiological condition of the difficult-to-root plants. Root-promoting substances in optimum dose speed up callus formation and production of roots and provide a well developed root system. Excessive concentration of these chemicals however, inhibits bud development and even causes the death of the cutting. The cost of raising cuttings in nursery is cheap. Mist propagation method of cuttings may also be tried for Muga food plants.

Cuttings should be selected from 1-1˝ years old (but not too old) branches with 2-active buds. Many cuttings may be prepared from a single branch. It is advisable to prepare cuttings early in the morning from suitable healthy young plants during February to April. In some cases cuttings may even be prepared during September-October also. The upper cut ends of the cuttings are to be sealed with wax or fresh cow dung to avoid drying or rotting. Cuttings are then put in the nursery beds in slanting position with spacing of about 30 centimeters. Holes for putting the cutting in the nursery beds may be made with the help of a hard stick/iron rod of appropriate size to avoid damage, Seedlings/saplings are to be kept in the nursery beds for about 2years before transplantation. They should be trained by removing their side shoots and apical tips.

3.2 Air Layerings: Air layering should be prepared during April-June (though it may be prepared in other season also) by removing a ring of bark (about 3 centimeters)  from suitable healthy branches (1-1˝ years old) of 4-5 years old Som and Sualu plants. This portion is covered with a mixture of compost, cowdung and soil in 1:1:1 proportion adding some moss/saw dust and wrapped with polythene paper/hession cloth. It is advisable to treat the cut with Seradix B3. Root would be seen after about a month under normal condition. Root promoting harmones are to be used for quick rooting. Air layering gives about 70% rooting, ensure quicker growth and plants would be dwarf and have more branches and leaves. The portion of the branch below the layer is cut and planted in nursery. It may also be planted directly in the pot. It is advisable not to select big branches or old trees for preparation of air layering. More number of layers will survive, if 50% of leavaes are removed from them at the time of plantation. The cost of raising layers in nursery is higher than the cuttings.

4. PLANTATION

4.1 Transplantation: Healthy seedlings/saplings with a ball of earth (about 15 cm diameter) are to be transplanted (remove from the nursery) during monsoon (May-August) when no watering is required without injuring their main roots. The earth around the seedlings/saplings up to the end of the root should be removed before two weeks of transplantation. It will help in sticking the ball of earth to the root system and settling the terminal roots at the time of transplantation. While transplanting, the position of the seedling/sapling/clone in the nursery is to be maintained as far as practicable to avoid physiological imbalance. Transplantation may be done in other seasons also where irrigation facility is available. Ring system watering during dry months is necessary for better growth of plants. Periodical removal of apical tips is necessary for seedlings/layers/saplings after transplantation.

4.2 Spacing: Spacing may vary from 3-6 meters depending on the slope of the land and its fertility. Plantation with closer spacing will produce more leaves and increase the income of the rearers. The close plantation may be pruned from time to time to adjust the rearing of early stage worms before transferring them to the tall trees. It will reduce the percentage of mortality and the cost of production. Hedge-Like plantation (spacing 2m x 2m) may be adjusted in such a way so that no transfer of worms will be required after exhaustion of leaves. Plantation of only selected edible Som and Sualu should be done variety-wise in separate plots for healthy growth of Muga-worms. About 600 plants may be planted in a hectare with a spacing of 4m x 4m and 500 plants with 5m x 5m.

4.3 Proper Facing: One should observe at the time of plantation that no hindrance in getting direct sunshine will be there for different rows of the plants. Plantation should usually be north-south direction. The wind direction is also to be noted. Digloti (a shruby plant) may be planted in between the rows of Som/Sualu to protect Mugaworms when they fall from Som/Sualu during strong wind and hailstorm in rearing period. A separate dwarf plantation with some shade trees should be there to rear the early stages of the Muga worms. Quick growing trees on western and southern sides of the Muga food plantation may be planted to serve as a wind breaker to protect the worms. Proper compound facing is to be provided for regular systematic plantation. Individual enclosure (ghora) is to be made for other plants to protect them from cattle, etc., in young age. There should be legislation or strict measures to control wanton felling of Muga food plants for increasing the area of plantation.

4.4 Ploughing: Light hoeing or ploughing is to be done twice a year in criss-cross manner. It would control weeds and prune the fibrous roots which feed on top soil. It would also help in the growth of the short and healthy shoots of the plants. Nowadays labour has become scarce and expensive and as such, the cost of weeding has increased greatly. Hence, chemical control of weeds may be practiced after a proper and detailed study of the weeds in the plantation. Selective herbicides, when will kill only the weeds are to be used for weeding considering however, their residual effects on the rearing of muga worms.

4.5 Manuring: Manuring (˝ cft in first year and 1 cft in subsequent years for each plant) should be applied once a year at the appropriate time (before monsoon starts) in a ring system around the base of the plants. It should be covered with earth to avoid loss due to heavy showers. It will increase the production of leaves and their quality. Fertilizers in appropriate doses may also be used for better growth of the plants and p

roduction of more leaves.

5. PRUNING

Muga food plants usually grow as tall tree. But we need dwarf trees with more branches and leaves for rearing Muga silk-worms. So, they are to be pruned from an early stage to keep them at a height of about 3-4 metres. To get the required shape and height, pruning at height, pruning at height of about one metre wuld give us the necessary branchings and leaves. Removal of terminal buds twice a year at a height of about two metres would also help to get more branches and leaves. Pruning and pollarding should be done at specific period so as to synchronise quality leaf production with the rearing period. Some of the trees may be pruned after completion of the first rearing of the year. Pruning should not be done during unfavourable seasons. Newly sprouted leaves of trees will help in rearing the subsequent crops. Pruning also will help in controlling some diseases and pests. Pruning of branches and fibrous roots of the plants in proper seasons simultaneously with manuring will increase shoots and leaf production. The cut at the time of pruning should be a slanting one to avoid water deposition. Fresh cowdung is to be applied at the cut end to save them from drying. Dwarf trees with more branches and leaves covered with wire-netted cages or nylon nets would make the supervision during rearing period easier. Moreover, control of pests and predators would be easy. Labour and expenditure will also be reduced. Pruning is also essential to rear the early states worm for better rearing results in every brood. Old trees without pruning and manuring will not yield healthy and nutritious leaves. Leaves will be hard and do not suit their (worms) digestion. By pruning in advance, trees will produce leaves of required age and newly hatched worms will start eating tender leaves. As the worms grow, the leaves too will grow and thus worms will get suitable leaves at each stage of their growth. Dry branches and nests of ants, etc., are to be removed from time to time for proper growth of the plants.

Wedding and loosening of the soil are to be done before the weeds flower and bear seeds.

Various Muga food plants cultivation can be taken up especially in newly terraced and jhumming areas for the benefit of the farmers. Plantation of various Muga food plants in waste land and in other available areas would also help in maintaining the balance of the natural environment as well as reducing the atmospheric pollution.

For successful muga rearing and more cocoon production, the leaves should be fresh an nutritious. So, the host plants are to be maintained in a scientific way.

The cost of plantation of one hectare of Muga food plants is about Rs. 2500 from seedlings and Rs. 3000 from layers.

   

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