BANANA (Musa spp)

Banana is a perennial tropical herbaceous plant consisting of an underground stem (corm) and a trunk (pseudo-stem) comprised of concentric layers of leaf sheaths. The plant originated in south East Asia. It is an excellent source of vitamin A, C, B, potassium and magnesium. Banana fruits provide fiber, are low in fat and sodium and cholesterol-free. They can also be planted for wind protection (windbreak) to a vegetable garden. The main areas of production in Kenya are Western, Nyanza, Eastern and Central regions.

Banana plot                                                                                                 ripe banana

Banana varieties

  Variety Remarks
Local Muraru They can be eaten as desert or cooked. Commonly grown in Central and Eastern Kenya
Kiganda
Improved Cultivars Apple (sweet banana) Recommended for export. Commonly grown in Central, Eastern and Western  Kenya
Gross Michel Resistant to panama disease
Kampala,Bogoyo Susceptible to Fusarium wilt
Dwarf Cavendish Resistant to panama disease
Giant Cavendish Resistant to panama disease.

Recommended for export

Williams Grows to 6 to 8 feet. They produce very large heads of fruit that are sweet and delicious. It is wind tolerant and cold hardy.
Grand Nain Early maturing

Big fingers

Uniform ripening

-grows from 6 to 8 feet tall

– Average sugar content

Vallery It is a Cavendish cultivar which is more resistant to panama disease than Giant Cavendish and can tolerate cold weather.

Recommended for export.

Paz Grown in Western and Nyanza
Lacatan Resistant to panama disease and can tolerate cold weather.

Recommended for export

Sabaki Recommended for export
Red banana Recommended for export

(All dessert type)

Uganda Green Recommended for export (all cooking type).
Ngombe

Gradishisikame

Mutahato

Mainly used for cooking.
Bokoboko Grown at the Coast of Kenya for multi-purpose use.
Mkonowa Tembo Roasted and cooked. Susceptible to Fusarium wilt and Sigatoka
Gold finger Newly introduced in Central Kenya for multi-purpose use.

 

Ecological requirement

Altitude

Altitudes of 0-1600m above sea level are recommended for banana production. This ranges from Coastal lands to lower highland zones.

 

Rainfall

An annual rainfall of 1000-2500mm is adequate for production. Optimal yields however require a well distributed annual rainfall of 1400mm or more, without dry spells. Irrigation is therefore necessary in low rainfall areas.

 

Soils

Bananas can be grown in a wide range of soils as long as there is good drainage and adequate fertility. Light to medium, well drained loam soils are the best. Fertile deep soils rich in humus should be chosen whenever possible. Recommended pH range is 5.5-6.5. Lime can be added to acidic soils in order to reduce acidity and provide suitable conditions for banana growing.

 

Temperature

The crop requires a warm humid climate for optimal growth with an average temperature of 20-300C. Below 200 C, normal plant growth is retarded. Lacatan and Valery are more tolerant to cold weather than other varieties. Cooler areas (higher altitudes) slow down plant development and the inflorescence may also fail to emerge.

 

Land preparation

Select land that is well sheltered to avoid wind damage. Plough the land during the dry season to eradicate weeds especially couch grass. Planting should be done at the beginning of the long rains. Recommended size of planting holes depends on water availability:

  1. Under dry condition (semi arid areas) :90 x 90 x 60 cm (3 x3x 2 feet)
  2. Under wet conditions :60 x60 x 60 cm (2 x2x 2 feet)

When digging the planting hole, separate top-soil (soil from the top 1 foot in a heap) and the subsoil (soil of the second 1 ft in another heap).

Mix 2debes (20-40 kg) of manure with the top soil and put the mixture in the hole.

 Propagation

The planting material most commonly used is suckers and tissue culture plants.

 

Suckers

Sword suckers are recommended for vegetative propagation. They emerge from the lower part of the stem and have narrow sword-shaped leaves. These are taken from parent plants when about 1m high and 15cm in diameter at the base. The first production is from 18 months.

 

Selection of a sucker

  1. Select from a healthy mother plant, without symptoms of pests or diseases such as banana weevil or nematodes
  2. Suckers should originate from heavy bearing mother plants with desirable characteristics.
  3. The sucker should be 1-2 m tall (except peeper sucker).
  4. The diameter of the sucker at the bottom should be 15-25cm.
  5. Suckers should have well developed strong roots.

 

Digging out suckers

  • Scoop away the soil between the mother plant and the selected sucker
  • Separate the sucker and the main stool by using a strong sharp pole or a special, flat iron digger.
  • Avoid any damages to the roots and stem of the sucker
  • Check for any symptoms of nematodes or banana weevil on the roots.
  • Nematodes are detected by the dark coloured roots. Split the roots and check the interior for confirmation; if the inside is black in colour as well, it is an indicator of nematodes.
  • Banana weevils are identified by larger black holes in the sucker.
  • Reduce the number of leaves before transporting or planting. Cut off the outer leaves
  • Transport under moist conditions. Cover with shading materials and sprinkle water on the roots.
  • Suckers should be stored for 3-5 days if they are placed in a hole and covered with soil
  • Plant at least within a week otherwise suckers may lose viability and die

 

Prophylactic treatment of suckers for nematodes and banana weevil

Pairing

Slice off the outer part of the sucker bottom. Remove all roots and scrape part of the stem with a sharp knife.

Dipping

Dip the banana suckers in a nematicide solution. The method is more costly than pairing.

 

Hot water treatment

Heat water until a candle just melts in it (55ºC). Remove the water from the fire and put the suckers in the hot water for 20 minutes. This reduces the danger of nematode infection.

Hot water treatment

 

 

 

Tissue culture plantlets

The use of tissue culture plant is the most recommended method of propagation. Because of the following advantages:

  • Rapid seedling multiplication
  • Healthy planting material free of diseases and pests.
  • Minimal replacement after planting and immediate continuation of growth.
  • Early bearing / maturity
  • Higher yields

 

Planting

  • The top soil and the sub soil should be kept separate.
  • Mix top soil with 1-2 ‘debes’ (about 20 -40 kg) of well decomposed compost manure and 150 g of TSP. To avoid nematode problems, add 100g nematicide to the soil mixture and mix thoroughly.
  • Fill only 2/3 of the planting hole with the mixture
  • Plant the banana sucker in the centre of the hole (45-60 cm depth) and use the sub-soil to fill up the hole. Water with 4-5 buckets of water for each sucker.

Use the sub-soil to fill up the Hole        Plant the sucker 45 cm – 60 cm deep

  • The banana stool needs some free space to establish itself in the first season. Cover the upper 1/3 of the planting hole with mulch and organic matter slowly in the next 3-4 months. The sucker will find its favourite position in the planting hole.

 

Fertilizer and Manure Application

At planting, about 150-200g of TSP or NPK (17:17:17) should be applied per plant. An early and good supply of nitrogen fertilizer is essential to accelerate the growth of pseudo-stems and ensure fast flowering. Bananas require large quantities of potassium and a fertilizer high in potassium (e.g. 20–10–20) should be applied every 2-3 months. An application of 250 – 300g of CAN should also be worked into the soil. It is recommended that 2-4 ‘debes’ of well decomposed farmyard manure is applied on the outer diameter of the canopy per stem per year just before the rains. A short forked hoe is used to incorporate the manure shallowly and carefully, to avoid root damage.

 

Spacing

For tall varieties:     4 x 4 m

For dwarf varieties: 3 x 3 m

 

Field Management

Irrigation

Water is needed particularly at flowering. In drier areas supplementary irrigation may be necessary during this time.

 

Mulching

Well maintained, heavy mulch will suppress unwanted weed growth, retain moisture, and provide humus for a good soil structure. Grass, banana leaves, or old pseudo-stems mulch can be used to recycle nutrients. The use of old pseudo-stems can encourage banana weevil infestations. The stems should therefore be chopped and dried before use.

 

Weeding 

Cultivation should always be shallow because bananas are shallow rooted. If mechanical weeding is done, care should be taken to avoid any disturbance of the roots. Earthing up of the stem base is required in windy areas.

 

Pruning and staking

  • To provide bigger and high quality bunches, bananas have to be desuckered regularly to control sucker growth. 3-5 pseudo-stems depending on variety and level of management should be allowed to remain on each corm:
  • Dwarf varieties such as Chinese dwarf should have 3 suckers per stool, consisting of a bearing mother plant, a large daughter and a small granddaughter sucker or pepper.
  • Medium and tall varieties such as ‘Williams hybrid’ and ‘Grand naine’ should have 3-5 suckers per stool.

Surplus suckers should be removed as early as possible in their development and perhaps used as planting material. Dead leaves should be removed at least twice a year.

After harvesting, the pseudo-stem should be cut off from the plant at ground level. Follower sucker selection is very important in order to avoid yield decline or ratoon crop.

The following are factors that need to be considered:

  1. a) The stage of plant development: Selection should be done when the mother plant is 1m tall.
  2. Number of suckers and direction of selection.

When the mother plant has reached 1m tall, three vigorous sword suckers facing eastward or up the slope, where the land is sloppy should be selected. All other suckers should be cut at the base, gorged out in the middle and killed with 2ml of kerosene or diesel.

After 1 to 2 months, the most vigorous suckers should be selected from the 3 suckers and the rest removed. This will be the first ratoon crop and the first sucker. The first sucker that is produced by the first ratoon sucker should be selected as the second ratoon crop. If the sucker selection is properly done, there should be a bearing mother plant, a large daughter sucker, a small granddaughter and a peeper all aligned in one direction.

Staking

This is necessary for the tall varieties. The fruit bearing pseudo-stem should be propped to prevent breakage caused by heavy bunches. Staking with wood or bamboo requires digging a hole about 40-60 cm deep at the base of the stem to install the prop. Tie the bunch to the prop near the portion where the fruit stalk emerges from the stem. Y- Sticks can also be used for staking.

Staking

 

Wind break

Strong winds can knock plants over or cause excessive leaf tearing. Planting in sheltered positions and in blocks, rather than in strips, is recommended. If planted in blocks, the plants shield each other against wind damage.

 

Fruit protection

Skin blemishes can ruin the value of the banana bunch. The bract and stem leaves that may rub against the developing fruit need to be removed on a regular basis.

The male flower bud is removed after it has grown 15cm below the last hand. Bagging developing bunches with polythene bags can be done to protect the fruit. The bags can be clear or coloured and are perforated to allow air circulation. Bagged fruit develops 3-4 days earlier.

 

Inter-cropping

In orchards with wider plant spacing, inter-cropping is possible during the entire cultivation period. Inter-cropping should be done with quick growing shallow rooted crops. However for orchards with closer spacing, intercropping can only be done in the first year.

 

Pests and Disease Management

Pests

Pest Damage / symptoms Control
Banana Weevil

(Cosmopolites sordidus)

The adult beetle is dark brown to black with a hard shell and can be recognized by its snout.

The adults are sluggish and appear dead when touched; hiding during the day and coming out at night to feed and lay eggs.

They feed on dead banana plants, newly cut stems and other decaying plant material near the base of the banana plants.

The larvae are dark, cream coloured and without legs and feed on corms making tunnels at ground level.

The pupa develops in the tunnels

Leaves attacked may turn yellow, wither and die prematurely. Heavy infestation may kill young plants while older plants are easily blown over by wind.

The pest is spread mostly by infested corms and causes major damage in neglected plants

Use uninfected plant material.

Do not leave planting material in the field overnight, since the beetles may lay eggs in it.

After harvest cut stems close to the ground and cover the cut surface with a layer of soil to prevent entry of the weevil.

Cut harvested stem in small pieces to hasten rotting.

Trap the weevils by placing old stem pieces facing downwards between plants. Trapped beetles can be collected by hand from pieces of the traps and killed by insecticide spray or the trap can also be treated with insecticide. Use of Mocap 2-3 times per year for contol of weevils

Banana silvering thrips (Hercinothrips bicintus) The adult pest is dark brown, 1.5mm long, with 2 pairs of fringed wings. It causes silvery patches on fruits which later turn brown. The skin of heavily infested fruit may crack permitting secondary infection which causes fruit rot.

It is affects the quality of bananas grown for export.

Use recommended insecticide e.g. Desis, Fastac at 7-14 days interval depending on level of infestation.
Nematodes (Radopholus similes) The symptoms are yellowing of leaves, growth cessation and retarded corm develop­ment. Severe infestations results in weak plants, poor growth, depressed yields and plant becoming susceptible to Panama disease.

The affected roots rot away. Mature plants may topple, and brown lesions form on roots in advanced stages.

The generation period is 20-25 days (egg to egg) in the soil.

It can be spread through irrigation water or through suckers used for planting.

Pair roots and discoloured tissues from suckers and treat with recommended nematicides such as Mocap, Nemacur

Trim all roots from suckers before planting.

 

Observe strict crop rotation by not

planting new bananas on old orchards with a history of weevil infestation for 12 months.

Uproot any volunteer banana plants.

Do not inter-crop bananas with crops which are hosts to nematodes e.g. maize, sorghum, and cow peas.

 

If nematodes are a serious problem, apply nematicide in planting holes and repeat spot application every 4 months. Soil fumigation in infected soil with (Nemasol-(2 Drench10L/M)) applied three weeks before planting

Diseases

Disease and causal agent Symptoms / Description Control
Cigar end rot (Trachysphaera fructigena) The fungus invades the dried flower parts and penetrates into the skin.

High humidity, poorly maintained plantations with overcrowded plants and abundant leaf trash favour occurrence of the disease.

The fruit tips undergo a dry rot with an ashy appearance that look like a cigar. The pulp eventually undergoes a dry rot and becomes fibrous.

Remove dry floral parts when dry 8-11 days after fruit bunch emergence.

Remove and burn all excess dried leaves and other plant debri from the field.

Bagging mature banana bunches.

Avoid overcrowding of plants by pruning excess suckers.

Panama Disease-Fusarium wilt (Fusarium oxysporium) It is caused by a soil borne fungus; spread through contaminated tools, infected plants, grazing animals and during transportation of young plants. Localized spread can occur along river banks by soil movement during flooding.

Diseased leaves turn yellow from the margin, dry up and later collapse leaving a skirt of dead leaves draped around plant.

The emerging heart leaf may die while stem remains standing until it decays and falls over.

Stems of affected plant split longitudinally and when cut across, the vessels exhibit purplish stains. Decayed stems smell of rotten fish while corms show brown or black lines running through the tissues when cut. Roots of diseased plant usually turn black and rot.

Use suckers from healthy plants or tissue culture plants.

Avoid injuring roots during weeding or other farm operations.

Avoid planting bananas on poorly drained soils.

Plant tolerant varieties e.g. GT, Pratta- Manyatta, Soth, Exera and Kifutu, Mysore, Cavendish, Uganda green, kisigame,

Sigatoka leaf spots Caused by various fungi e.g Cercospora, Alternaria and Mycospherella. This disease forms well defined long grey spots with a black ring and an outer yellow halo. Remove badly spotted leaves and leaf trash and destroy them.

 

Avoid overcrowding of plants by removing excess suckers and leaves.

Bacterial Xanthomonas wilt (BXW)

(Xanthomona scampestrispv. Musacearum)

 

Initially one of the youngest three leaves turns pale-green or yellow and breaks down at the petiole and the pseudo stem. Later all the other leaves collapse around the pseudo stem. An infected finger shows dry and rotten pulp that is colored brown or black and the presence of bacterial discharges. Use disease-free planting materials.

 

Remove and destroy infected plants from fields.

 

Black leaf streak (Mycosphaerell afijiensis) (also called black Sigatoka)

 

It is a very serious disease that affects banana leaves. Infection occurs through the leaves. The lesions gradually grow larger and kill large areas of the leaf. This results in lower yields and causes premature ripening of the fruit.

 

Remove and destroy diseased leaves by burning or burying to reduce source of infection.

Avoid overhead irrigation; under-canopy micro-irrigation or drip-irrigation is preferable.

Avoid overcrowding and limit the sheltering of the plants

The bunchy top disease (Viral disease)

 

It is a viral disease transmitted by aphids.  A few dark-green streaks or dots usually appear on the minor veins and the midrib of the second leaf. They are best seen from the underside of the leaf in transmitted light. The ‘dot-dash’ symptoms can sometimes occur on the petiole. The successive leaf may display whitish streaks along the secondary veins when it is still rolled which become dark green as the leaf unfolds. Successive leaves become smaller with chlorotic, upturned margins. The leaves become dry and brittle, and are more erect than normal giving the plant a rosetted ‘bunchy top’ appearance.

Infected plants rarely produce a fruit bunch after infection and do not fruit in subsequent years. Plants infected late in the growing cycle may fruit once, but the bunch stalk and the fruit will be small and distorted. On plants infected very late, the only symptoms present may be a few dark green streaks on the tips of the flower bracts.

Use of virus-free planting material.

Remove and destroy diseased plants. The whole stool, including rhizome/corm and all associated suckers, should be destroyed by uprooting and chopping into small pieces, as the virus can ultimately spread to all parts of the mat. Control should be practiced across the whole production area to avoid the rapid re-infection.

 

Anthracnose (Colletotrichum musae)

 

It is an important post-harvest problem of bananas especially during transport and storage. On green fruit, pin-size brown or black sunken spots develop. Infection in young fruit is not always manifested until the fruit ripens, when black, round, slightly sunken spots appear. The centres of the spots become dark because of the formation of small black fruiting bodies of the fungus. Under moist conditions, masses of spores are produced having a characteristic salmon (pinkish) colour. Pulp of diseased fruit is usually not affected unless the fruit is over-ripe. Practice field sanitation

 

Minimize bruising during fruit handling

 

Hot water treatment of the fruit for 5 min at 50°C.

 

Use clean handling equipment and facilities

 

Banana Xanthomonas Wilt Disease            Fusariumwilt ( Panama )symptoms

Fusarium wilt (Panama)      Cigar end rot

 

Anthracnose fruit                       Toppled bananas due to root damage by nematodes

Banana weevil borer                      Banana silvering thrips

Fruit fly damage banana aphids

Banana bunchy top                      Black leaf streak on banana leaf

Banana bunchy top

Harvesting

The time from planting to harvesting ranges between 9-12 months depending on area and variety. Bananas are harvested when still green at varying stages of maturity depending market requirement.

Maturity indices vary widely among varieties and include angularity or fullness of fingers, as well as colour change. Immature bananas are very angular but fill out to a rounded shape at full maturity. Fingers are considered mature when three quarters appear light green and shiny.

During harvesting, bunches should never be dropped on the ground, to avoid fruit damage. For home consumption, the bunch is cut from the stem after fingers begin to turn light green and the edges of the fruit change from angular to round.

Bananas harvested at this stage will ripen within 2 weeks. After harvesting the bunch, the pseudo-stem is cut off with a clean implement at ground level. The cut surface is covered with soil to avoid entry of the banana weevil.

The average yield is 35-40 tons/ha under good management. The economic lifespan of a banana plantation is 8-10 years, after which productivity declines and replacement of the plantation is recommended.

 

Post-harvest Handling

  1. Packaging

The banana should be de-handed before packing. The bunch is hung on the de-handing rail and using a sharp chisel or knife, the crown is cut off from the bunch stem. The hands are left to bleed for 10 minutes and then split into units of 5-6 fingers. The units are washed, flower remains removed and hand splits dried on clean benches. The damaged, deformed and loose fingers are sorted out. The hand splits should be dipped in a suitable fungicidal solution (1gm/litre of water, to control crown rot. The graded bananas are packed in plastic crates to protect them from mechanical damage.

  1. Ripening

Bananas are ripened while either in crates or in ripening chambers. Stack crates in the ripening chamber and place an ethylene source in the chamber sump e.g. Passion fruit, papaya, avocado, apple and tomatoes. The chamber is closed for 24-30 hours and opened to release carbon dioxide and to break the peel colour. Graded bananas should be loosely packed in a ripening chamber.

Utilization

The fruits are used for cooking and desert. The greener, less ripe bananas contain higher levels of complex sugars and have a “starchier” taste. On the other hand, ripe bananas taste sweeter due to higher levels of simpler sugar concentrations. They are eaten as fresh fruit and used in fruit salads.

Other Users

Banana Chips – Both the green and ripe bananas can be used to produce banana chips and fritters though green ones are preferred. The fruit is peeled, thinly, sliced then deep fried.

 

Ripe bananas are also used for making ice-cream and yoghurt flavouring. The fruits can also be made into jam or juice.

 

Banana Flour – The fruits are dried and ground into flour which can be made into banana bread, pancakes, cakes and other baked products.

 

Banana Alcohol – Ripe bananas are juiced and then fermented.

 

The male flowers can be used as a vegetable, but they have to be heated briefly in salty water to remove the bitterness.

 

Other banana products

Banana Clothing– the fibre from the banana pseudo stem is dried, processed, dyed and made into exotic clothing and other woven products such as baskets and mats.