Bananas are tropical perennial plants whose fruits are used both for cooking (plantains) and as table fruits (dessert). They may also be processed into starch, chips, puree, juice, beer (in Africa), vinegar, or may be dehydrated and sold as dried fruit. Flour is produced from both plantains and table bananas, which can then be used in soups, baking or as a drink. The flowers can be used as a vegetable. The fresh leaves have a high content of protein and cattle and chicken like them because of their taste. The leaves and stem are also used for mulching, thatching houses, wrapping, decorations, making mats and as ropes.
In many of the lower altitude wetter areas of East Africa, bananas are a major staple food. They are mostly grown as a subsistence crop, although there is much internal and regional trading.
Banana crops planted in trenches Banana crop at maturity
Ripened banana fruits
The site should allow adequate sunlight for flowering and fruiting. The site should also have good drainage and windbreaks since bananas are sensitive to water lodging and to strong winds, which shred the leaves, cause crown distortions and blows plants over.
Ecological requirements for the crop are as follows:
Bananas thrive well within altitudes ranging from 0-1800 masl. The ‘Dwarf Cavendish’ variety, however, can grow well upto 2100 masl.
Soil type and conditions
Bananas prefer well-drained, deep, fertile, light to medium loamy soils rich in organic matter. Ideal Soil pH is 5.5 – 6.5 (4.5 -7.5). Under very acidic conditions, liming is recommended.
For optimal production, temperatures should be in the range 20 – 30 oC. Plant growth is retarded and chilling injury occurs below 13 0C.
For survival, rainfall of about 1000 – 2500 mm p.a is adequate, but in order to achieve good yields bananas should receive 200-220 mm water per month as a regular supply.
To avoid crop lodging due to the absence of windbreaks, the crop should be grown in wind sheltered positions or in blocks rather than strips. If planted in blocks, the plants protect each other against wind.
Recommendations for land preparation
- Clear the land and remove stamps and any other roots from previous vegetation. The cut vegetation will provide green mulch that should be in cooperated back into the soil when ploughing.
- Plough the land using appropriate tools such as chisel ploughs, hand hoes, oxen or tractor drawn implements. Plough deep and harrow.
- Consider conservation agriculture techniques in subsequent years to conserve soil, water, nutrients and to reduce cost and workload.
Consider minimum tillage in subsequent years to conserve soil, water, and nutrients, and to reduce cost and workload.
(i)Tissue Culture (TC) plantlets; or
(ii)Suckers (corms, peepers, sword suckers, maiden suckers)
Select planting materials from healthy plants free of pests and diseases and having all the desirable bunch qualities.
(i) Tissue Culture (TC) plantlets
TC plantlets are banana suckers obtained from the laboratory. Tissue culture banana seedlings for planting should be at least 200-300mm high at planting and have 5 healthy dark leaves.
Purchase TC bananas from accredited nurseries/ institutions like JKUAT, KALRO and Private certified companies.
TCgives the cleanest possible plantlets free from pests and diseases.
Suckers for planting can be the corms, the peepers, the sword or the maiden suckers. These should be obtained from healthy plants free of pests and diseases. To eliminate any doubt, undertake paring (root trimming) and hot water treatment for suckers before use as planting materials. This process involves the following:
· Trimming all the roots from the sucker.
· Cutting off 1cm of tissue around the corm until a clean white tissue appears.
· Preparing hot water. Heat water until a candle just melts in it (55 0C).
Remove the water from the fire and put the suckers in it for 20 minutes.
In Kenya, a wide range of banana varieties are grown.
Varieties grown include:
(i)Cooking types: Ngombe, Nusu Ngombe, Kisii Matoke, Uganda green, Murule, Mutahato, GradiShisikame.
(ii)Ripening types: Giant Cavendish, Dwarf Cavendish, FHIA 17,18,23, Grand Naine, Poyo, Valery, Williams hybrid, Vallery, paz, Lacatan, Gross Michel, Apple, Uganda red, Peripeta.
(iii)Dual purpose: Nusu Ngombe, FHIA 18, Eshinamuli, Muraru, Bokoboko, Mkono watembo.
The most suitable planting period is at the beginning of the rainy season.
Bananas can be Planted as a pure stand or in a mixed cropping system.
The procedure in planting banana is as follows:
· Prepare holes 60 cm wide x 60 cm deep, preferably before the onset of rains. In areas with marginal rainfall, the holes should measure 90 cm x 90 cm x 60 cm.
· Put topsoil (first 30 cm) on one side of the hole and sub-soil on the other side.
· Mix 10-20 kg of farmyard manure or compost with the topsoil.
· Spacing depends on the variety to be planted;
Short varieties like Dwarf Cavendish – space at 3m x 3m.
Taller varieties like Giant Cavendish, FHIA – space at 3x4m
· Plant at the beginning (onset) of the rainy season to ensure good establishment.
· Make a hole in the centre of the main hole then put the recommended basal fertilizer and mix with mixture of manure and topsoil.
· Plant the sucker or TC seedlings in the hole and firm at the base.
· For corms- plant 15 cm deep into the hole.
· For suckers- plant 60cm (2ft) tall sword sucker (with long internodes- sign of fast growth), not water sucker. Treat with hot water where necessary.
· For T/C seedlings- plant 30cm (1ft) tall seedlings with 5-7 leaves. Harden seedlings before planting.
Intercropping: Young banana plants are excellent nurses for other crops like the pulses. During the first year, bananas should be intercropped with shallow rooted crops for ease of weeding and for maximizing land use.
The best soil for bananas is a deep, friable loam with good drainage, aeration and high organic matter content.
Bananas, therefore, respond well to application of well decomposed good quality manure or composts.
Conduct soil test/analysis before establishing the crop. Repeat soil test/analysis after 3 years.
Nutrients required for crop growth include nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S), boron (B), chlorine (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), and zinc (Zn).
Add manure and fertilizers to the soil in the right amounts to provide the required plant nutrients for vigorous crop growth.
At planting use recommended rate of basal fertilizer as per the soil analysis results.
Replenish nutrients as per recommendations of soil test and analysis results.
· Top dress with 200g DAP and 200-300g CAN per stool per year in a circle of 50-100 cm diameter, depending on soil analysis results
· Apply 5-10kg compost of farmyard manure per stool/year
In order to achieve good yields, supplementary irrigation is necessary, especially in areas with long dry seasons where rainfall is less than 220 mm per month, to avoid drying up of the crop.
Commercially used varieties cannot endure stagnant water conditions, so flood irrigation should only be used if the soil has good drainage.
Frequent shallow weeding is necessary until the plants shade out weeds.
Manage weeds through weeding, intercropping or mulching;
Intercrop with cover crops like legumes especially in the first year for ease of weed management
· Weed the plant around the basin, 4-6 weeks after establishment to allow free air flow and to control pest- and disease build-up.
· Perform frequent shallow weeding to keep the field free of weeds.
-Water application in the right proportions during dry spell;
-Nutrient application in the form of compost or organic materials or fertilizers;
-Weeding or mulching;
-Monitoring pests and diseases for action.
-Pruning/desuckering. is very important for passion fruit. Ensure this is done regularly
• Intercrop with legumes such as Mucuna pruriens, Dolichos lab lab or cowpeas to suppress weeds and to act as green manure to help supply nitrogen and maintain soil fertility;
• Mulch around the basin, 30 to 50 cm (60 cm) away from the plant/stool, to reduce weed emergence, to maintain a layer of humus, to enhance microbiological activity in the soil, to maintain moisture, to help roots to bury deep in the ground, and to help control banana weevils
• Prune or de-sucker to allow 1 (one) flowering or fruiting stem and 2-3 suckers of different ages (sizes) for continuous banana production. Fewer suckers per stool results in fewer but bigger bunches. Many suckers on a stool results in a large number of small bunches per stool.
• Support (prop) the fruit-bearing pseudo-stem with wooden or Y-sticks to prevent breakage caused by heavy bunches.
• Remove the male buds after completion of finger formation.
• Change banana crop after 10-15 years and rotate with other crops like cereals to break pest and disease cycle and to avoid disease build-up
Adult weevil Corm damage by the larvae (grubs)
Symptoms/Damage: Grubs feed in the corm and rootstock, making irregular tunnels. Tunnels are roughly circular and can reach upto about 8 mm in diameter. The corm can be riddled with tunnels, which promotes fungal infection and decay reducing it to a black mass of rotten tissue. Injury to the corm interferes with root initiation and sap flow in the plant. As a result, the leaves turn yellow, wither and die prematurely. Young suckers show symptoms of wilting and die, but older plants are retarded in growth. Heavily infested plants produce small bunches, and are easily blown over by the wind.
Damage is worst in neglected plants. In fertile soils and with good crop husbandry, it is seldom serious.
- Use clean planting material. Planting infested suckers increases damage.
- Paring (trimming) and Hot water treatment: If clean planting material is not available, the available planting material should be pared (trimmed) to reduce the number of eggs/ grubs and subsequently subjected to hot water treatment (dipped in hot water at 55oC) for 20-30 minutes. However, badly damaged suckers should be discarded.
- Trapping: Old pseudostems can be cut into lengths of 20-60cm and split each length, and placed on the ground near the corm bases with the cut surface downwards. Adult weevils get attracted to the cut stems or corms to feed and to lay eggs. The weevils can be collected by hand and destroyed.
- Apply 60-100 g of neem seed powder or neem cake at planting and then at 4 months intervals. At planting, dip suckers in a 20% neem seed solution to protect them from weevil attack
- Field sanitation: Practise good crop hygiene by cutting old stems after harvesting at ground level, covering the ground portion (rhizome) with a layer of soil (to prevent weevil entry) and breaking the pseudostems (stumps) into smaller pieces and scattering them so that they quickly dry out. Alternatively, cut (break) into larger pieces and use for trapping weevils.
- Practise good crop husbandry to produce vigorous banana plants, which are more able to tolerate weevil damage.
- Crop rotation
Radopholus similis, the burrowing nematode, is the most economically important nematode parasite of banana.
Toppled bananas due to root damage caused by Radopholus similis the burrowing nematode
Above ground symptoms include stunted plant growth and lack of vigour; reduction in the number and size of leaves; leaf yellowing; premature defoliation; increased susceptibility to wilt; reduced yield (small bunches); increased harvest-to-harvest time and plant toppling.
Symptoms/Damage: The most dramatic symptom is the uprooting (toppling) of plants. Burrowing nematode feeding destroys anchor roots and makes plants susceptible to toppling, especially when fruiting or during strong winds. Additional aboveground symptoms include slow sucker formation, delayed fruiting, smaller fruit, reduced bunch weight and shortened plant life.
Burrowing nematodes on roots
Below ground symptoms include reddish-brown lesions on larger root surfaces, both at the point of entry and throughout the cortex. Eventually, burrowing nematodes migrate from roots into the rhizome causing black, circular lesions, hence the name blackhead disease.
· Use clean planting material, obtained from tissue culture.
· Rogue infested plants
· Biological control using Paecilomyces lilacinus, a fungus, which parasitizes the egg, larva and adult of the nematode.
· Incorporate neem cake powder (nematicidal) into the soil near the banana plants.
· Plant few seeds of Mexican marigold to control nematodes and uproot before seeding.
Aphids on banana leaf
Symptoms/Damage: Aphids are tiny black and green soft- bodied insects which suck sap from leaves and stems of the plant. Symptoms of attack include:
· Colonies of aphids clustered on underside of leaves
· Wilting and distortion of leaves and young shoots
· Yellowing and premature death of leaves and young plants.
· Honey dew on leaves which enhances the growth of sooty mould which diminishes the photosynthetic capacity of the leaf.
Aphids also spread banana bunchy top viruses.
- Aphids are usually controlled by natural enemies (Conserve natural enemies).
- Monitor the crop regularly.
· Apply insecticidal soaps or oils such as neem.
· Spray with appropriate insecticides eg Kingcode Elite 50EC, Pentagon 50EC, if infestation is high (follow IPM rules).
To get rid of the sooty mold, spray with Jambo clean (100ml/20L).
(iv) Banana silvering Thrips
Is a minor pest in Kenya
Silvery thrips effects on fruits
Symptom/Damage: Thrips feed on the skin of the fruit causing silvering patches which, on close inspection, can be seen to be speckled with dark excrement. In some instances, browning of fruit may occur and deep longitudinal cracks may appear as a result.
Usually the damage is minor and infrequent.
- Use clean planting material
- Bagging of bunches
- Conserve and preserve natural enemies, such as predatory thrips, lacewings and predatory bugs.
- Spot-spray with botanicals or other biopesticides if damage becomes excessive (e.g. neem extract, pyrethrum, a mixture of garlic and pepper).
- Remove the male floral parts 8-11 days after fruit formation.
Symptoms/Damage: Mole infestation is evidenced by existence mounds with chunks of dirt. When a mound dirt is removed, mole tunnels can be seen. Damages occur to the banana roots due to their digging and tunnelling as they forage for food which includes earthworms, grubs, snails, spiders, small animals and insects. The tunnels damage the roots of the plants, prevents uptake of water and nutrients which eventually causes the plants to die.
- Use traps with baits.
- Keep the basin of banana stools always moist as moles do not like living on wet grounds.
- Do not heap/mount soil around the basin of the banana stool as this might become a hide out for the moles.
- Intercrop with Tefrosia, Simsim and jack beans for controlling moles
- Apply pig manure (a repellent) to the roots of the crop.
- Use Rodenticides
Fruitfly on banana.
Symptoms: The most visible signs are the presence of the adult flies and the pupae near the decaying fruit.
· Bagging (wrapping) of banana fruits to protect from attack by fruit flies. It serves as a barrier to oviposition.
· Keep bananas at low temperatures to freeze them. Fruit flies are known to struggle at lower temperatures.
· Use a fruit fly trap with a sticky attractant to prevent them from flying away once they land on it.
Use herb repellants eg basil plant.
The effects of these diseases on banana production are:
· Poor crop establishment
· Plant loss
· Failure to produce healthy suckers
· Reduced bunch weight
· Shortened plantation life span
(i)Banana Xanthomonas Wilt
BXW infected field
Symptoms/Damage: Symptoms appear on the leaves, floral parts and on the pseudostem:
On the leaves, infestation leads to a gradual turn to yellowing and lifeless appearance as if they were melting under intense heat. They eventually turn brown and die.
In flowering plants, a drying rot and blackening of the male bud appears, starting with the outer bracts and eventually extend to the rachis. The fruits ripen unevenly and prematurely, turning from green to yellow and black rapidly. The pulp of the rotting fruits shows rusty brown stains.
BXW - Bud-Fruit symptoms
Internal symptoms of an infected pseudostem are yellow-orange streaking of the vascular tissues and the presence of a yellow bacterial ooze, which can also be seen from any other infected plant part.
· Use resistant varieties, if available.
· Use certified disease-free planting material.
· Remove male flower buds after the last hand has set fruit to prevent transmission of bacteria by insects.
· Remove infected plants from fields and destroy them.
· Clean farm equipment using disinfectants like JIK to avoid transmission through contaminated tools.
· Keep animals away from banana plantation.
· Follow national regulations (local quarantine and restrictions, e.g. do not sell banana bunches from infected areas in BXW free areas)
(ii)Fusarium wilt (Panama Disease)
Cause: Fusarium oxysporum
(ii)Fusarium wilt (Also known as Panama disease)
Fusarium is a soil borne fungus that enters the banana plant through the roots. As the disease progresses upward through the plant, it clogs the vessels and blocks the flow of water and nutrients.
Fusarium wilt infested banana field
Symptoms/Damage: The fungus invades the vascular tissue causing discolouration and wilting, eventually killing the plant.
Internal symptoms include vascular discolouration, which varies from pale to yellow in the early stages to dark red or almost black in the later stages.
Fusarium pseudostem symptoms - Pith discolouration
Split pseudostem Leaf collapse at the petiole
Effective chemical and biological treatments aren’t yet available. Use:
· Clean planting materials
· Crop rotation
· Field sanitation practices: -Remove and burn infected plants as soon as possible to check the spread of the diseases.
Cigar-end rot symptoms on banana fingers
Symptoms/Damage: The disease attacks the ripening fruit of banana, causing a dry rot of the flower end that produces an ash grey wrinkled lesion similar to the burnt end of cigar. In storage or during transport the disease may progress to involve the whole fruit.
· Field sanitation
· Avoid damage to the fruit and deflower 8-11 days after fruit bunch emergence.
· Bagging of maturing banana stems.
(iv)Black sigatoka (Black leaf streak)
Cause: Ascomycete fungus
Black leaf streak (black Sigatoka) on banana leaf Symptoms/Damage: The disease attacks the leaves of the plant causing dark leaf spots that eventually enlarge and coalesce, causing much of the leaf area to turn yellow and brown.
· Use resistant varieties
· Remove and destroy diseased leaves
· Avoid overhead irrigation
· Avoid overcrowding of plants
· Bagging of mature banana stem
· Pruning and de-suckering
· Apply appropriate pesticide using IPM principles
Cause: A fungus Colletotrichum musae that survives in dead or decaying leaves and also on fruits.
Anthracnose disease in banana fruit
Symptoms/Damage: The fungus causes dark-brown to black, sunken spots on the peel of infected fruits.
(i) Preventive measures
· Avoid damage to the banana tissue during harvest, packaging and storage.
· Use plastic sleeves after bunch emergence to protect them from contamination.
· Clean processing stations and storage facilities to prevent post-harvest contamination.
· Wash fruits with water to rid the skin from fungal spores.
· Remove decaying leaves and remaining floral parts.
(ii) Chemical control
· Spray harvested fruits (banana bunches) with products containing mancozeb or benzimidazolesand coat the fruits with food-grade chemical butylated hydroxyanisle (BHA).
(iii) Biological control
Treat fruits at harvest with biofungicides.
Maiden suckers (5-8months old) take 9-12 months to fruit.
Sword suckers (about 75cm high) take 18 months to fruiting
Peepers sucker (young and small) take 24 months before fruiting.
The most common index of maturity is based on the fruit fingers of the banana. The more rounded a finger is in a cross-section, the more mature it is. The fingers are considered mature for harvesting when they are 3/4 round (75% maturity) and still green.
Harvesting banana bunches is usually spread evenly throughout the whole year. It is very important that bunches do not fall or bump during harvesting or transportation, as this causes them to blacken and rot.
Harvested bunches should be kept in the shade. It is advisable to handle and transport banana hands rather than the whole bunches because this reduces physical damage.
Ripening is increased when bunches are packed in closed chambers with restricted air circulation
Bunches must be handled gently to avoid bruising.
Farmers usually transport and market bananas in bunches. This form of handling exposes the fruits to mechanical damage thereby reducing their quality.
In order to reduce damage in post harvest handling processes, it is advisable to remove the hands and pack in reusable plastic containers.
Banana will produce the first yield about 18 months after planting. Tissue culture bananas yield considerably higher than traditionally propagated bananas when planted in clean soil that has not been previously used for banana production in the recent past.
Average yield in Kenya has been 6 tons/acre but under good management yields of 20 tons/acre can be achieved.
Processing products include Flour, bread, wine crisps, cakes, juices, jams/jelly, sweets, among others.