MULBERRY (Morus alba)
Mulberry is a flowering plants in the family of Moraceae. Immature fruits are white or green to pale yellow with pink edges. In most species the fruits are red when they are ripening, turning dark purple to black and have a sweet flavor. The fruits are succulent and have many juicy seeds fused together.
There are three main species of mulberry trees:
- White Mulberry (Morus alba) – most species produce red fruits that gradually darken to an almost black color when ripe. White mulberry fruits are generally very sweet but often lacking in needed tartness. However, one variety, Whitey White, produces very sweet, plump berries that are actually white in color.
- Black Mulberry ( nigra L.) – the berries change from pink to red and finally a black colour upon ripening. The fruits are large and juicy; with a good balance of sweetness and tartness that makes them the best flavored species of mulberry.
- American Mulberry, Red Mulberry ( rubra L.) change in colour from white, to pink and eventually a deep red when ripe. The fruits have a flavor that almost equals that of the black mulberry
There are many hybrids between the red and white species. The varieties grown in Kenya are shown in the table below:
|Moras alba (Ex-Embu)
||This variety is characterized by short internodes, reddish bark, and small leaves
||It is drought resistant.
|Moras alba (Ex-Thika)
||This variety is characterized by large light green leaves. It has long internodes and a whitish bark
||It is fairly drought resistant.
|This variety has medium heart-shaped smooth light green leaves.
||It roots easily and is drought resistant.
It is suitable for both silkworm rearing and berry production.
|This variety has small finger shaped deeply serrated leaves.
||It is a heavy berry producer, hence not recommended for silkworm rearing.
|Moras alba var. Kanva (Ex-India)
||This is characterized by medium heart shaped leaves that have glittering appearance. The stem has short inter-nodes with a lot of leaves.
||It is a heavy berry producer and is recommended for both silkworm rearing and berry production.
It roots easily and grows fast.
||It has medium heart-shaped leaves, dark green in colour with glittering golden tops. The inter-nodes are short with a lot of leaves.
||It roots easily.
||This variety has lobed, medium sized leaves that glitter with short internodes, and a whitish bark.
||It roots slowly.
||This variety has large, dark green leaves that are heart-shaped with a glittering appearance. The stem has long inter-nodes and a shinny bark.
||It roots slowly but when established grows very fast.
It is drought resistant.
It is a heavy yielder, and has out-yielded all other varieties.
It is recommended for most areas.
||This has long thick finger like leaves and short inter-nodes
||This variety has small thin and rough finger-like leaves that resemble a reduced size of the Ichinose. It tends to produce a number of thin branches.
||It is recommended for berry production because it is a heavy berry producer.
||This variety has big heart-shaped leaves. The stem has long inter-nodes and few leaves on the branches.
||It is drought resistant
Mulberry performs well at 700-2200m asl. High altitudes areas where frost is likely to occur are unsuitable for production.
It requires a minimum rainfall of 800mm per year. Although it is drought resistant, supplementary irrigation may be necessary in areas where rainfall is less than 800mm per year.
The soils should be deep, well drained, fertile and with good water holding capacity.
Ideal production temperature is 26oC-28oC
Land should be prepared early before the rains. Perennial weeds such as couch grass and rhizomes should be removed. On steep land with over 30% slope, construction of terraces should be done.
Mulberry is propagated vegetatively by cuttings, layering or grafting. Propagation by cuttings has been widely used and is the current recommended practice. Seeds are only used in plant breeding work. Obtain cuttings from healthy strong branches that are at least four months old. These should be made from the grey part of the branch, and should measure 15-20cm with at least three buds. They should be cut slightly slanting at the top 2cm above the bud and sloping upward 2cm below on opposite side of the bud. Cuttings should be planted immediately or stored in a reasonably moist place before planting.
- Make a raised bed 1 m wide by desired length.
- Add 150g of double super phosphates and 4 – 6kg of well rotten manure per square meter.
- Plant cuttings at the spacing of 15cm x 20cm and shade the bed lightly to minimize evaporation.
- At this spacing, the nursery bed should contain 1000 cuttings. Water the beds regularly and transplant the seedlings after 3-4 months.
- Reduce the shade gradually one month before transplanting so that the plants are hardened to tolerate sunshine after planting.
- Plant the seedlings in a spacing of 1.5m x 0.7m in manual cultivation or 2.2m x 0.7m in mechanized cultivation.
- Dig holes 50cm deep and 40cm wide.
- Separate top soil from sub soil.
- Mix the top soil with 40g DSP and 10kg well-rotten manure per hole.
- Half fill the hole with mixture to form a basin. At the onset of the rains plant seedlings in the basin so formed, at least 10cm below ground level. The remaining space will subsequently be filled up with more soil when the shoot sprouts and this will encourage the formation of more secondary roots.
- The plant population is 9523 plants/ha
Mulch the seedlings 15cm away from the stem.
After planting, only one strong shoot should be selected and allowed to grow. The rest are pruned off at early age .When the selected shoot is 50 – 60cm high (knee-high) a base prune should be done at soil level. This is roughly four months after planting.
When more shoots come up after the base pruning, select three strong shoots and place soil between them to spread them. When these shoots attain 60cm height they are pruned to the height of 30cm above the ground. This is about three months from base pruning. More shoots will come up; allow two or three shoots per tree.
After every leaf harvest, apply 150g CAN in a split application of 75g and 10kg well rotten manure per tree per year soon after the onset of the rains.
Pests and Diseases
Although there are no pests of economic importance on mulberry, the following pests and diseases have been observed to attack the plants:
|These lodge and suck sap from on the young branches and leaves
They secret excess sap which blackens leaves
|Remove and burn infected leaves
|Septoria leaf spot
|This manifests itself in form of dark brown spots with clear boundaries and a white centre. Occasionally the spots enlarge to cover the whole leaf.
||Remove and burn infected leaves as early as possible.
|Powdery Mildew (Leveillula taurica)
||The symptoms include greyish white spots on the underside of leaves. The spots gradually expand and join.
The underside of the leaves appear as if dusted with white flour.
|Plant resistant varieties.
Remove and burn the infected leaves and check the spread of the disease.
Harvesting of berries
Mulberries fruits are harvested by placing a large clean sheet under the area of the tree and shaking the branches so that the berries can fall on the covered ground. Picking ripe mulberry fruit is often difficult because they are fragile and tend to break open easily. Unwashed berries will keep several days in a refrigerator in a covered container.
Fruit yields are estimated at 4-14 tons/ha (2.3-12kg/tree/season). Up to 20tons per hectare of mulberry leaves can be expected after the 3rd year of growth, and this should feed silk worm to give up to 500kg of silk cocoons per hectare. The silk is span into balls and eventually made into cloth.
Some varieties are recommended for berry production.
- Mulberry leaves, particularly those of the white mulberry, are ecologically important as the sole food source of the silkworm (Bombyx mori), named after the mulberry genus Morus), the pupa/cocoon used to make silk.
- The berries can be eaten fresh or used for making juices, jams, tarts, stews and wines. Mulberries blend well with other fruits, especially pears and apples.
- The leaves can be eaten as a vegetable, livestock feed or as a dyeing material. Inside the seed is a yellow drying edible oil rich in iodine containing liquid fatty acids (80-90%) that has saponification value making it suitable for toilet soaps.
Note: Mulberry fruit is mildly toxic if eaten before ripening and becomes either red or black when ready for harvest.