Banana

Description

The banana plant, Musa paradisiaca, is the world's largest herbaceous perennial plant and belongs to the family Musaceae. It is grown for it's fleshy, curved banana fruit. The plant is tall, tropical and tree-like with a sturdy main pseudostem (not a true stem as it is made of rolled leaf bases) with the leaves arranged spirally at the top. The leaves are large blades with a pronounced central midrib and obvious veins. They can reach up to 2.7 m (8.9 ft) in length and up to 0.6 m (2.0 ft) in width. Each pseudostem produces a group of flowers which may also be called the 'banana heart' from which the fruits develop in an hanging cluster. The banana fruits are comprised of a protective outer layer, or skin, with numerous long, thin strings that run between the skin and the edible inner portion. The seeds are tiny black specks running through the center of the fruit. In commercial plantations, the parent banana plant dies after harvest and is replaced with a daughter plant. However, a plantation can grow for 25 years or more if managed properly. The trees can reach heights between 2 and 9 m (6.6–29.5 ft). Bananas may also be referred to as plantains and the cultivated varieties are derived from ancestors which originated from the Malaysian peninsula, New Guinea and South-East Asia.


Uses

The fruit is the most widely used part of the plant and can be eaten fresh or cooked or processed into starch, chips, puree, beer, vinegar or dehydrated to produce dried fruit. The fruit may also be processed into flour which is used in baking, soups or beverages. The flowers of the plant may be used as a vegetable. Fresh leaves have a high protein content and can be fed to cattle. Other uses for leaves include polishing floors, lining pots or wrapping food.


Propagation


Basic requirements
Bananas grow best in hot and humid climates, require a rainfall of at least 1000 mm (39.4 in) per year to survive and have a high light requirement. Banana plants grow optimally at 27°C (98.6°F) and require a deep soil, rich in organic matter which is well draining and well aerated. The plants will grow optimally in soil with a pH between 5.5 and 7.0. Young banana plants are very susceptible to wind damage and it is recommended that they are planted in sufficient shelter or in a block so that the plants will protect one another.

Suckers
Banana plants are vegetatively propagated, most often from suckers (shoots that grow from a bud at the base of the plant) or from corms (underground bulbs known as rhizomes). The use of whole corms is very laborious so it is more common to grow from small pieces of corm. There are three different types of banana suckers which are produced by the mother plant; maidenheads, sword suckers and water suckers. Maidenheads have a large pseudostem which does not produce fruit. Sword suckers have a narrow base, short pseudostem and narrow, blade-like leaves. They produce healthy, fruitful pseudostems when they mature Water suckers have short pseudostems and broad leaves. Water suckers are not strongly attached to the rhizome and generally produce weaker plants and less fruit. Maidenheads and large sword suckers are preferred over water suckers.

Planting
The desired pieces of the plant are usually planted 30–60 cm (11.8–23.6 in) deep in the soil and should generally be planted at the end of the dry season or the beginning of the wet season. Plant spacing is dependent on the cultivar being planted. Frequent weeding is required until plants are tall enough to shade out competing plants and should be started about 6 weeks after planting. The banana plants are fast growing and require the frequent addition of nutrients as well as additional irrigation in the dry season. Banana is often grown alongside other crop plants with similar requirements, indeed, the young banana plants make excellent 'nurses' for other crops such as papaya or cocoa which can be grown very close to the young banana.


References

CABI Crop Protection Compendium. (2008). Musa datasheet. Available at: http://www.cabi.org/cpc/datasheet/351... 05 November 14]. Paid subscription required.

Crane, J. H., Balerdi, C. F. & Maguire, I. (2008).Banana Growing in the Florida Home Landscape. University of Florida IFAS Extension. Available at: http://edis.ifas.ufl.edu/pdffiles/MG/.... [Accessed 06 November 14]. Free to access.

Ploetz, R. C., Zentmyer, G. A., Nishijima, W. T., Rohrbach, K. G. & Ohr, H. D. (Eds) (1994). Compendium of Tropical Fruit Diseases. American Phytopathological Society Press. Available at: http://www.apsnet.org/apsstore/shopap.... Available for purchase from APS Press.

Sauls, J. (2003). Growing Bananas. Texas Cooperative Extension, Texas A&M University, College Station, Texas. Availablable at: http://aggie-horticulture.tamu.edu/ne.... [Accessed 06 November 14]. Free to access.



Common Pests and Diseases

Banana speckle
Mycosphaerella musae

Symptoms
Cause
Comments

Rhizome rot
Erwinia carotovora
Erwinia chrysanthemi

Symptoms
Pseudostem breaks from rhizome; rhizome will not germinate; internal tissue yellow/brown and watery
Cause
Bacteria
Comments
Bacteria live in soil and enter plant through wounds; disease encouraged by wet, humid conditions
Management
Select only high quality, disease-free rhizomes fro propagation; disinfect all tools used for propagation regularly; allow seed pieces to dry before planting

Banana bacterial wilt (BBW) / Banana xanthomonas wilt (BXW)
Xanthomonas campestris pv. musacearum (Xcm)

Symptoms
The infected plant shows yellow leaves which later turn brown and die. If infection occurs at later stage of crop, male buds exhibit dry rot and blackening . Premature uneven ripening of fruits in the bunch. The infected fruit show rusty brown discoloration in pulp.
Infected parts ooze yellow bacteria after cut.
Cause
Bacteria
Comments
In Uganda locally it is called as 'kiwotoka'. The disease is mainly transmitted by insects, farm equipments, animals and infected rhizomes. BBW was first recorded in Ethiopia (1968) mainly on banana and enset. Later the disease spread to Uganda (2001) and eventually to other eastern African countries.
Management
Use disease free planting material. Roughing of infected plant and destroy them. Removing of excess male buds prevent disease spread. Disinfect the farm equipments.

Moko disease
Ralstonia solanacearum

Symptoms
Older leaves chlorotic, wilted and collapsing; spreads to entire canopy; collapse of pseudostem
Cause
Bacterium
Comments
Can be spread root to root or by insects or human activities such as machete pruning.
Management
Banana plantations should be regularly monitored for presence of disease; if Moko is present, male buds should be removed and all tools thoroughly disinfected; infected plants may need to be destroyed along with any neighbouring plants

Black sigatoka (Black leaf streak)
Mycosphaerella fijiensis

Symptoms
Red/brown flecks or spots on underside or topside of leaves; spots with dark or yellow border and grey centre; death of leaf surface; bunch not developing
Cause
Fungus
Comments
Currently the most important disease of banana; promoted by high moisture and spores spread by wind
Management
Export plantations may require regular fungicide applications; increase plant spacing to improve air circulation and reduce humidity; remove leaves with mature spots

Anthracnose
Colletotrichum musae

Symptoms
Brown spots on fruit peel; large brown to black areas; black lesions on green fruit.
Cause
Fungus
Comments
Wet conditions promote growth and spread of disease; spread by rainfall through plant or banana bunch.
Management
Commercially produced fruit should be washed and dipped in fungicide prior to shipping; protect fruit from injury; remove flower parts which can harbour fungus.

Panama disease (Fusarium wilt)
Fusarium oxysporum f. sp. cubense

Symptoms
The fungus infect roots and grow inside xylem vessels which in turn blocks flow of nutrients and water to plant. We can see reddish brown discoloration of vascular tissue by cut opening rhizomes and pseudostem.
The above ground symptoms are yellowing of older leaves; splitting of leaf sheaths; leaves wilting and buckling; death of entire canopy.
Cause
Fungus
Comments
It is very lethal disease which mainly spreads through soil, running water and infected rhizome. It is one of the first disease of bananas to have spread globally.
Management
Use disease free planting materials; currently no effective treatment once plants are infected.

Yellow sigatoka
Mycosphaerella musae

Symptoms
Pale green flecks on leaves which enlarge to chlorotic streaks; streaks enlarge and turn brown with chlorotic halo; mature lesions are gray with a dark brown border; lesions coalesce and kill large areas of leaves
Cause
Fungus
Comments
Spores spread by wind, rain and irrigation water;
Management
Export plantations may require regular fungicide applications; increase plant spacing to improve air circulation and reduce humidity; remove leaves with mature spots

Cigar end rot
Verticillium fructigena
Trachysphaera theobromae

Symptoms
Tips of fingers initially begin to darken and wrinkle; tips of fingers develop a dark rot; if Verticillium fungi are present then the rot is typically dry and the tips become mummified, if Trachysphaera is present, the rotted are become covered with white spores which gives the fingers the ashen appearance characteristic of cigar end rot.
Cause
Fungus
Comments
Disease is of economic importance in Central and West Africa; it also occurs in India, Iran, South Africa, South America, the Canaries and the West Indies.
Management
Infected flowers should be removed from the plant; bunches should be bagged using perforated polyethylene; chemical control may be necessary in the case of severe infestations.

Cordana leaf spot
Cordana musae

Symptoms
Initially the lower leaves shows oval shaped yellow or pale brown spots near the leaf margins. As the disease progress, the central dead brown area of spots is covered by concentric zonation which is surrounded by a yellow halo. The individual spots may join together to form large necrotic area.
Cause
Fungus
Comments
The disease is favored by hot and humid condition. The pathogen mainly spreads by water splash and wind.
Management
Remove all the infected leaves and burn them. If the disease is severe spray copper based fungicides.

Banana aphid
Pentalonia nigronervosa

Symptoms
Deformed plants with curled, shriveled leaves; if infestation is severe, galls may form on leaves; colonies of aphids usually present in crown of plant at base of pseudostem or between the outer leaf sheaths; aphid is soft-bodied and red-brown to almost black in color.
Cause
Insect
Comments
Colonies are often tended by ants; populations can build rapidly during warm weather.
Management
Chemical control does not provide protection against transmission of Banana bunchy top and direct feeding damage is not usually severe enough to warrant spraying; insecticidal soaps can help control aphid populations; plants infected with bunch top should be removed and destroyed to prevent spread.

Coconut scale
Aspidiotus destructor

Symptoms
Small, flat, whitish scales, usually on undersides of leaves but may also attach to petioles, peduncles and fruit; plant tissue discolored and yellowing.
Cause
Insect
Comments
Coconut scale attacks a large number of hosts including coconut and other palm species, avocado, cassava, papaya, guava and sugar cane; most common in tropical regions.
Management
Biological control is the best way to manage scale, with lady beetles providing the most effective protection.

Banana weevil
Cosmopolites sordidus

Symptoms
Reduced plant growth; reduced fruit production; tunnels may be visible in corm as rounded holes up to 8 mm in diameter; plants wilting and toppling over; destruction of root system; plant death; adult insect is a hard-shelled beetle which is almost black in color; adult is commonly found between leaf sheaths; larvae are creamy-white, legless grubs with a red-brown head
Cause
Insect
Comments
Insects are nocturnal, feeding and mating only at night
Management
Plant only healthy plant material, do not plant if any tunnels are visible; hot water treatment of clean trimmed suckers can be used to kill off many eggs and grubs; applications of neem powder can reduce weevil numbers; appropriate insecticides applied at time of planting can help control weevil numbers

Banana skipper
Erionota thrax

Symptoms
Usually larvae feed on leaves. Typically the feeding involves incising and rolling up of leaves.
Cause
Insect
Comments
The insect also attacks coconut and other palm species. The pest is common in Southeast Asia and Pacific islands.
Management
Encourage and release natural enemies to check the population of skippers. Hand pick the larvae and kill them.

Bunchy top
Banana bunchy top virus (BBTV)

Symptoms
Dark green streaks in leaves; chlorotic and upturned leaf margins; leaves brittle and erect; plant has a ‘bunchy top; no bunches produced
Cause
Virus
Comments
Aphid transmitted; when infected symptoms appear after two more leaves are produced
Management
Plant less susceptible varieties; destroy infected plants to prevent spread of disease

Banana mosaic
Cucumber mosaic virus (CMV)

Symptoms
Chlorotic mottling or stripes on foliage; distorted fruit which may have chlorotic streaks or mottling; distorted leaves; leaf necrosis
Cause
Virus
Comments
Transmitted by aphids; may be transmitted through infected seed
Management
Remove susceptible host plants from around plantation; plant virus-free material