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Table Of Contents

Table Of Contents

Pests and Diseases

Description of Mango Cultivars

Further Reading

Contributors

Glossary

Index

 
 
 
 
 
Mango Growing in Kenya 
by 
Juergen Griesbach

 
 

Training Materials Coordinator - Jan Beniest

Editors - Anne Marie Nyamu and Tony Simons 

Table Of Contents

 

Introduction

Although the mango tree is not indigenous to Kenya, it has been cultivated in the Coast Province for centuries. Traders in ivory and slaves brought seed into the country during the 14th century. Mango trees were reported in Somalia as early as 1331. The mango is one of the most important fruit crops in the tropical and subtropical lowlands. It is native to India, Bangladesh, Myanmar and Malaysia, but can be found growing in more than 60 other countries throughout the world (Salim et al., 2002).

The mango is best adapted to a warm tropical monsoon climate with a pronounced dry season (>3 months) followed by rains. However, information from other countries indicates that crops cultivated for a long time over an extended area show a high degree of diversity due to varied environmental influences. This was likely also true for the mango seedlings first introduced in Kenya which were all polyembryonic. They can be multiplied by seeding and generally produce true-to-type progeny. Some of these are still productive, e.g. along the Tana River, and some of them have been given names which to this day are still valued. Kitoovu, Kimji, Klarabu, Punda and Mayai are of poor quality but better known are cultivars like Apple, Ngowe, Boribo, Batawi and Dodo. Of these, a few have steadily lost ground to a generation of cultivars introduced in the 1970s and 1980s distinguished by greater resistance to anthracnose (Colletotrichum), powdery mildew (Oidium), their very attractive colour and good shelf life.

Uses and Food Value

The mango—because of its attractive appearance and the very pleasant taste of selected cultivars—is claimed to be the most important fruit of the tropics. It has been touted as ��king of all fruits�� but has also been described as a ��ball of tow soaked in turpentine and molasses�� by critics! It is one of the most delicious fruits there is, although it has undesirable features including coarse fibrous strands through the flesh and the pungent and turpentine flavours of some cultivars.

Fruits from the scattered mango production areas are mainly consumed locally. During the last 20–30 years, commercial mango production was developed based on locally adapted and newly imported cultivars. This has seen the area under mango cultivation in Kenya rise from 500 ha in 1970 to approximately 15,000 ha in 2000 (source: Annual Report, Ministry of Agriculture, Nairobi). There is a great diversity of mango fruit types which permits considerable manipulation for various purposes and markets: juice, chutney, pickles, jam/jelly, fresh fruit, canned and/or dried fruit etc. Given the multiple products, it is therefore a potential source of foreign exchange for a developing country; it is also a source of employment for a considerable seasonal labour force.

In addition to income opportunities, the mango is noted for combating nutritional disorders. The mango compares favourably in food value with both temperate and tropical fruits. Indeed the fruit contains almost all the known vitamins and many essential minerals. Studies have shown that one mango fruit can provide a large proportion of the daily human requirements of essential minerals, and vitamins (see Table below). The calorific value of mango is mostly derived from the sugars. It is as high as that of grapes and even higher than that of apple, pears or peaches. The protein content is generally a little higher than that of other fruits except the avocado. Mangos are also a fairly good source of thiamine and niacin and contain some calcium and iron.

 

 

Botany

The mango is a member of the family Anacardiaceae. This family comprises many other valuable trees such as the cashew and the pistachio nut. The genus Mangifera includes 25 species (Mabberly, 1997) with edible fruits such as Mangifera caesia, M. foetida, M. odorata and M. pajang, although M. indica, the mango, is the only species that is grown commercially on a large scale. Worldwide mango cultivation now covers approximately 2.9 million hectares (FAO, 2001) and earns nearly US$ 500 million in export revenues.

There are two races of mango—one from India and the other from Southeast Asia. The Indian race is intolerant of humidity, has flushes of bright red new growth that is subject to powdery mildew and anthracnose and bears mono-embryonic fruit of high colour and regular shape. The Southeast Asian race is tolerant of excess moisture, has pale green or red new growth and resists powdery mildew. Its polyembryonic fruit is pale green and of an elongated kidney shape.

The mango is a deep-rooted, evergreen plant which can develop into huge trees, especially on deep soils. The height and shape varies considerably among seedlings and cultivars. Under optimum climatic conditions, the trees are erect and fast growing and the canopy can either be broad and rounded or more upright. Seedling trees can reach more than 20 m in height while grafted ones are usually half that size. The tree is long-lived with some specimens known to be over 150 years old and still producing fruit! The mature leaves are simple, entire, leathery, dark green and glossy; they are usually pale green or red while young. They are short-pointed, oblong and lanceolate in shape and relatively long and narrow, often measuring more than 30 cm in length and up to 13 cm in width (Salim et al., 2002). New leaves are formed in periodic flushes about two to three times a year.

The greenish-white or pinkish flowers are borne in inflorescences—usually placed terminally on current or previous year��s growth—in large panicles of up to 2000 or more minute flowers. Male flowers usually outnumber the bisexual or perfect flowers.

Generally, flowering in Kenya lasts from about late July to early November, depending mostly on weather conditions. At the coast it is not uncommon to find individual trees flowering as early as February and March. Pollinators are usually flies, rarely bees or nectivorous bats. Pollen cannot be shed in high humidity or rain as this might prevent pollination and fruit setting. Mangos are self-fertile, thus a single tree will produce fruits without cross-pollination.

Mango fruits of the various cultivars differ greatly in shape, size, appearance and internal characteristics. The fruit is a fleshy drupe, varying in size from 2.5 to 30 cm long, may be kidney-shaped, ovate or round and weigh from approximately 200 g to over 2000 g. The leathery skin is waxy and smooth and when ripe entirely pale green or yellow marked with red, depending on the cultivar.

The fruit quality is based on the scarcity of fibre, sweetness and minimal turpentine taste. The flesh of the improved cultivars is peach-like and juicy, of a melting texture and more or less free from fibre. The single, compressed ovoid seed is encased in the white fibrous inner layer of the fruit. The seed is enclosed in a stony endocarp, varying in size/shape with two fleshy cotyledons. Each seed contains either one embryo (the so-called mono-embryonic cultivars) or more than one embryo (the so-called polyembryonic cultivars), producing several seedlings without fertilization. Most of the seedlings will be nucellar seedlings which have originated vegetatively, they are mostly true-to-type and genetically identical with the mother tree. Most Indian cultivars are mono-embryonic, while generally cultivars from Indonesia, Thailand and the Philippines are polyembryonic.

Propagation

Mangos are propagated either vegetatively or by seed. Seedlings are grown sometimes to produce new cultivars but mainly for use as rootstocks or to reproduce known polyembryonic cultivars. Mono-embryonic types, however, require vegetative propagation to retain all of the desired characteristics. It is also known that trees grafted on selected rootstocks remain smaller than the rootstock, and bear better and earlier.

The selection of suitable rootstock is as important as the selection of the scion cultivar. It has a strong influence on the growth, yield, fruit maturity and soil adaptability, among other things. In Kenya, the uniform seeds of the polyembryonic cultivars Sabre, Peach and Dodo are routinely used successfully. Seeds must be taken from ripe fruits and should be as fresh as possible at the time of planting. Before planting, the hard woody endocarp should be removed to examine the seed for disease or any damage caused by the mango weevil (Sternochetus). Freshly sown seeds should be protected from high temperatures and dessication by providing shade. Once seedlings emerge the shade is removed to harden the plants and produce a sturdy stem for grafting.

Once the seeds have germinated, the seedlings are carefully lifted and culled. This may be about one month after planting when they have reached the 3-5-red-leaf-stage. After transplanting the seedlings into containers not smaller than 18 x 35 cm they remain there until they are of pencil thickness at about 20 cm above soil level. There are many techniques used to graft mango seedlings, but the most common methods are side-graft, side veneer and wedge- and whip-graft. A mango tree must never be transplanted while it is flushing or when the leaves are still tender; the best time to transplant is after the second flush has hardened.

 

The top-working of fruit trees is a normal orchard practice and is necessary to replace old cultivars/seedlings with improved selections which are developed from time to time. Top-worked trees will start bearing within 2–3 years, i.e. much earlier than a newly planted tree. Furthermore, the survival of newly planted trees is not always guaranteed (drought, fire, animals, etc.).

Establishment

Mango is successfully grown on a wide range of soils. The trees do well in sandy soils at the coastline as well as on loam, black cotton and even murram soils at other elevations. The essential prerequisites for good development of the trees are deep soils (at least 3 m), appropriate rainfall (500–1000 mm), good drainage, suitable altitude (0–1200 m) and preferably a pH value of between 5.5 and 7.5. The tree itself is not difficult to grow and, once well established, is relatively tolerant of drought, occasional flooding and poor soil condition. Irrigation in the first years after planting promotes flushing (and suppresses flowering), so that tree size increases quickly. Irrigation also widens the scope for intercropping, for example, with papaya, banana, pineapple or vegetables, during the establishment phase. When the trees are big enough to produce a substantial crop, irrigation is stopped, or at least interrupted long enough to impose quiescence leading to flower initiation.

Among the various climatic factors, temperature, rainfall and humidity have a greater bearing on mango production than irrigation and soils. Furthermore, the production of high quality mango fruit does not depend so much on elevation but on the range of temperatures available. The two important considerations for mango cultivation are a dry period at the time of flowering—in Kenya mainly during the months of August to October—and sufficient heat during the time of fruit ripening. For optimum growth and productivity, 20–26��C is believed to be ideal. Temperatures exceeding 40��C may, especially in hot/dry areas, lead to sunburn of fruits and stunting of tree growth. Although not very impressive, mango trees of selected cultivars like Sabre and Peach have been observed at elevations of up to about 1900 m. However, for more successful crops areas below 1200 m should be considered.

The amount of rainfall in a given locality is not as important as its intensity and distribution. Rainfall of 500–1000 mm at the right time of the year is sufficient for successful cultivation. However, the mango cannot do well in areas which experience frequent rains or very high humidity during the flowering period. Such conditions are not conducive to good fruit set and they increase the incidence of serious diseases like powdery mildew and anthracnose. Anthracnose can be a major problem as the same organism occurs on avocado, coffee and papaya. Powdery mildew is quite common when low temperatures accompany high humidity (see Appendix 2).

Since the mango is a long-lived perennial, the planting distance usually depends to a large extent on the vigour of the cultivar/rootstock and on the environment. Most orchards (either solely mango or a few trees on small farms) are planted too densely and trees are forced to grow upright and tall. Overcrowding results in the production of fewer fruits which are apt to be poorly coloured and infected with diseases. Tall trees also present a harvesting problem and create difficulties during spraying and pruning. Normally, grafted trees are spaced at 8 x 10 m or 10 x 12 m, though at the coast seedlings require 12 x 14 m. Intercrops of short-lived fruit trees such as papaya or annual crops could be used for better utilization of land in widely spaced young plantations.

Maintenance

Mango plants should develop into strong well-shaped trees within the first 4 years and do not require pruning unless there are excessive branches or the shape is unusual. Depending on the cultivar and growth pattern selective pruning of branches may be required to encourage growth of lateral branches and to ensure development of good tree architecture for future fruit bearing. Any branches on the trunk lower than one metre from the ground should be cut. In later years, pruning is done mainly to remove diseased and/or dry branches or those touching the ground or crowding others. Grafted trees tend to flower from the first year, and the formation of fruit on year-old mango trees is nothing exceptional. Flowering at this early stage and especially early bearing weakens young trees and often damages them severely. Therefore early flowering has to be avoided by removing the inflorescences; only from the third or fourth year should trees be allowed to bear fruits.

A general criterion regarding mango nutrition is that care must be taken not to over-fertilize thereby promoting vegetative vigour at the expense of flowering and fruit set. This is particularly true for nitrogen application since trees are subject to fertilizer burn. Correct fertilizer requirements can only be determined by means of leaf and soil analyses taken in different agroclimatic regions. With trees in fruit, proper timing is critical and it is recommended that fertilizer be applied just after harvesting, during the rains. In general, a tree at full bearing age (7 years and older) needs about 1.5 to 2.5 kg of Calcium Ammonium Nitrate (CAN) (26%); 2.25 kg superphosphate and 0.75–1.5 kg potassium chloride per year, or the equivalent inputs from manure or compost for small-scale farmers. These quantities can be supplied either at one time or may be split into two doses administered with a two-month interval between them.

Orchards should be kept clean, especially under the canopy of the trees where the fertilizer is spread uniformly in a circular belt around the drip line. This is the zone where the most absorption roots are located.

Production

Mango seedlings as a rule start to bear fruit within 4–7 years, while grafted trees (if allowed) may bear a few fruits in their second year in the field. Mango production in Kenya has to be differentiated according to the production system. There is traditional mango growing, and commercial and market-orientated mango cultivation. Out of an average annual mango production in Kenya of about 140,000 tonnes (t) during 1999/2000, approximately 3300 t (2.3%) were exported (source: Annual Report, Horticultural Crops Development Authority (HCDA), Ministry of Agriculture, Nairobi). Some distinct differences between the location of production and the performance of the orchard can be identified, such as the harvest period, the fruit quality and the yield level. Due to the varying ecological conditions in Kenya, mangos are available almost all year round (see Appendix 3).

In the main production area, the Coast Province, two supply seasons can be differentiated. The first and main season runs from November to February and the second from June to August. In areas of higher altitude such as Murang��a and Mwea (Central Province), the harvest season is 4–6 weeks later than at the coast, with a peak in February and March. The mango picking season in Kenya competes with that of other mango producing countries (Mexico, Brazil, India, Pakistan, Israel, South Africa) and extends over a period of between 5 and 6 months (Appendix 4). Interestingly though, Kenya exports only about 3000 t out of the worldwide export tonnage of 580,000 t/year (FAO, 2001).

Productivity depends on a number of factors, including quantity of previous crop, weather and soil conditions, altitude, control of pests and diseases, fertilization and cultivar. Even in the case of the same cultivar, yields vary greatly because mango is grown under widely varying agroclimatic conditions and cultural practices.

Biennial or irregular bearing occurs often with the mango and it is common for some cultivars to bear heavily in one year and sparsely the next. One of the reasons for this phenomenon is that trees over-bear in one year, thus inhibiting adequate flower bud formation the following year. Under these circumstances, it is difficult to get accurate local long-term yield records. However, it is well known that yields of 25 t/ha and more for Kent, Sabine, Tommy Atkins and Keitt are not uncommon.

Cultivar trials carried out under rainfed conditions at government prison farms in Kenya indicate that even higher yields could be achieved. Tables 1 and 2 show the performance of some imported mango cultivars planted in the Central Province of Kenya. Additional performance figures are also shown in these tables which are taken from Griesbach (1992, page 87).

Maturity

Depending on cultivars and environmental conditons it takes 90 to 160 days after flowering for Kenya mangos to reach maturity. Not all fruits on one tree will ripen at the same time. A great problem is to determine precisely the stage at which the fruit is ripe for picking. Fruits harvested too early will be of inferior quality after storage; however, fruits picked when too ripe cannot be stored for any length of time and may give rise to problems such as jelly seed. The fruit will have its best flavour if allowed to ripen on the tree. None of the tests (acid, sugar content or specific gravity) used to determine ripeness, however, are fully reliable.

The fruits are generally picked when they begin to change colour. This may occur first in a small area or the change will cover most of the fruit��s surface. However, one destructive maturity test that can be applied even before the external colour break starts is to examine the colour of the flesh around the seed. When this begins to change from green-white to yellow or orange, it indicates that the fruit is beginning to ripen and may therefore be picked. Also the greater the swelling of the shoulders above the stalk attachment, the riper the fruit is likely to be (see diagram of a mature mango fruit).

During and after harvesting the highly perishable fruit must be handled with the greatest care. The fruit is removed from the tree by cutting the fruit stalk about 2 cm from fruit. This will prevent the latex (exuded from the cut stalk) adhering to the skin of the fruit, staining it and rendering it unattractive. Ladders or long picking poles with a cutter blade and an attached canvas bag, held open by a ring, are also in use. To avoid physical damage, the picked mangos should be carefully placed into clean wooden or plastic containers and never into gunny bags. If there is a delay in the transfer of the fruits to a store or packing shed they should be kept in a sheltered place to minimize sunburn, loss of moisture and accumulation of dust.

After any sorting, grading, washing, fungicidal treatment and perhaps waxing, the fruits are ready for packing, preferably into shallow single-layered trays of 4–5 kg each. Because mangos are harvested during the summer months, the fruit temperature may be as high as 35��C and more. This has a detrimental effect on the shelf life of the fruit. It is therefore advisable to move the packed fruits into cold storage as quickly as possible to help them lose this inherent heat. The recommended storage temperature must, however, not drop below 7��C (range: 7–10��C) as otherwise cold injury may occur.

Flower Induction

 

According to the Horticultural Crops Development Authority (HCDA), mangos in Kenya are available from November to April (and sometimes to July). Because of less competition better prices are fetched in Europe and the Middle East between November and December (see Appendix 5). Many techniques have been used in other countries to improve productivity and to alter the cropping season. Smudging (moist organic material—grass, leaves, etc.—is slowly burnt under the tree canopies and the resulting smoke induces flowering) is an old technique reported from the Philippines for enforcing off-season flowering, but this has largely given way to chemical induction. The application of potassium nitrate has been commercially accepted. The reasons are obvious: to have an altered earlier harvest, to take advantage of the good market price, to fill the gap of under-supply and to have flowering during a dry spell with little or no fungal diseases.

The readiness of a tree to flower is an important factor for a successful operation. For best results, choose trees with leaves that are dull green or greenish-brown and brittle when crushed by hand. The trees should have an appearance of suspended growth or be dormant. It is easier to induce mango trees to flower towards the dry season, and older trees respond better than young ones.

It is recommended that a 1% potassium nitrate solution mixed with a sticker agent (adhesive) be sprayed on to the tree, totally drenching its terminals and leaves. Make sure a knapsack sprayer has no residual herbicide in it before beginning to spray. If the timing is right, flowers will emerge 10–14 days after application. Tentative trials have been successfully implemented in Kenya.

Pests and Diseases

Although the mango in Kenya is spread throughout all feasible agroclimatic zones it has relatively few major problems with pests and diseases. These problems can be significantly reduced through a number of management decisions, for example:

    • selection of proper orchard site

    • selection of cultivars

    • controlled fertilizer application

    • timely spray application programmes

    • orchard sanitation

    • timing of irrigation

However, even when implementing these decisions there is no guarantee that some of these stubborn pests/diseases will not occur. Trees should be examined frequently to check for any infestations so that control measures, particularly for export fruits, can be applied before extensive damage can occur.

Where specific insecticides/fungicides have been mentioned in the following text, these are generally given as examples and should not be regarded as exclusive of others. In addition, trade names have been avoided as much as possible as one active ingredient could have several trade names from different manufacturers. It is important to rotate pesticides so that no resistance can build up especially in the nursery. The author has previously used the pesticides mentioned during his field research trials although the reader is strongly advised to check with his/her horticultural extension officer for the latest control recommendations and the respective recommended pre-harvest intervals (see Appendix 6).

In areas where chemical control agents are not available or affordable it is possible to use phytopesticides. Tephrosia vogelii and Azadirachta indica (neem tree) are probably the most readily available.

Anthracnose

Besides powdery mildew, anthracnose, caused by the fungus Colletotrichum gloeosporioides, is undoubtedly the most common and widespread fungus disease of mango and is a major factor limiting production in areas where conditions of high humidity prevail. The fungus invades inflorescences, fruits, leaves and twigs. Substantial losses due to this disease are recorded every year not only at premature stages of the crop but also during storage after picking.

Humidity, rains and heavy dew during critical infection periods greatly increase the disease incidence. Most infections occur from the beginning of flowering in gradually decreasing severity until the fruit is about half-grown. Infections on the flower and panicle appear first as minute brown or black spots which slowly enlarge. Infected flowers usually wither and die before fruit set.

Young fruits are readily infected. Spots may remain as pinpoint latent infections or they may enlarge in wet weather. Wet weather also causes characteristic tear-stain symptoms due to the spread of fungal spores by raindrops. The latent infections on young fruits cause much of the decay which occurs in mature fruits. Nearly mature to ripe fruits will have black spots of varied form which may be slightly sunken and show surface cracks penetrating deeply into the fruit causing extensive rotting or complete blackening of the fruit surface.

To control the disease, orchard sanitation and pruning of dead twigs and branches—which may harbour the fungus—are the principal control measures used to reduce the source of a new infection cycle. The widespread occurrence of the inoculum of the fungus makes it impossible to control the disease by pruning and the removal of dropped leaves alone. To be more successful, the above mentioned measures have to be supplemented by spray applications using Mancozeb, copper oxychloride, Maneb, Propineb, Benomyl etc.

It is recommended to start spraying at the stage of flower-bud formation. During flowering/fruit set and until the fruits have developed to half their size, spraying should take place at fortnightly intervals. After this, it is sufficient to treat the trees once a month. It is very important to apply a full cover spray for the first two applications. Since this period is also the critical stage during which powdery mildew and the mango weevil attack, counteractions should be implemented using recommended fungicide/insecticide combinations.

All cultivars are to some extent susceptible to anthracnose. The range of resistance (with Tommy Atkins being the most resistant) is: Tommy Atkins, van Dyke, Sabine, Ngowe, Gesine, Apple, Keitt, Kent, Kensington, Chino, Sensation, Batawi, Boribo, Haden, Maya.

There are several other diseases of mango fruits that have been reported occasionally. These include alternaria rot, mango scab, stem-end rot, algal leaf spot and sooty mould.

Mango Fruit Fly

Different types of fruit flies are known to attack ripening mangos in almost all mango-producing areas. Yield losses of more than 50% have been reported. Ceratitis cosyra followed by C. rosa and C. capitata have been found to be the major pests of mango.

The females lay their eggs under the surface of the fruit skin. After hatching, the maggots penetrate the flesh and destroy the fruit from inside. The infested part becomes mushy and causes premature colouring of the already useless fruit. Fruits of some cultivars are more susceptible to attack than those of others. Successful control of fruit flies in mango orchards depends on a combination of:

• eradication of non-economic host plants (such as neglected citrus, peach, guava)

• regular orchard sanitation

• determination of population density by using traps

• regular poison-bait applications

Chemical control of adult fruit flies in orchards is based on a weekly bait spray: protein hydrozylate or molasses mixed with Malathion, Trichlorphon, Fenitrothion or Fenthion. The bait is applied in large drops at a rate of 200–1000 ml/tree, depending on tree size. It is not necessary to wet the whole tree; only part of the foliage needs to be covered.

Mango Seed Weevil

The weevil, Sternochetus mangiferae (F), is a common pest in Kenya and can be found in all local mango-growing areas. It is spread mainly by transportation of infested fruits since the weevil develops within the mango seed and can therefore be transported easily from one locality to another unnoticed. The mango weevil does not usually damage the fruit and consequently is not a serious pest as far as local consumption of the fruit is concerned. However, this pest hinders the development of a fresh fruit export market because the leading import countries in the Middle East and other places maintain strict quarantine regulations.

Infestation symptoms are most obvious within the seed where the weevil largely completes its life cycle. Here all stages of the insect development—larvae, pupae and adults—can be found. Externally the affected fruits appear normal, but very often are rotting from inside.

The female usually lays her eggs over a period of 5–6 weeks on fruits before these are half-grown. The hatching period is 3–5 days. The young larvae penetrate the fruit and eat their way to the seed where they feed and develop into adult weevils. These emerge from the stone by tunnelling outwards through the flesh and skin of the fruit, leaving an unsightly patch where rotting soon sets in. Once the weevils have left the fruit they search for a hiding place such as beneath loose bark of trees or in waste material under the trees where they spend the time of the year that is unfavourable for them.

To date, chemical control measures against this pest have not proved economical. However, implementing the following three steps will definitely reduce the weevil population in the orchard.

Sanitation of orchard and yard

The biggest source of infestation is dropped fruits or seeds lying around in which weevils can survive up to about 300 days. Therefore, regular removal and destruction of waste material up to the end of the harvesting period is very important and effective.

Treatment of trunk and branches

The most suitable stage for control is during the emergence and oviposition of the adult weevil. The first step to suppress the weevil population is implemented at the beginning of the mango flowering season by using preferably long-lasting contact insecticides such as Azinphos, Endosulfan, Malathion and Fenthion. It is important to thoroughly wet (by spraying) the bark of the trunk and scaffold branches or brush the insecticide mixed with a suitable carrier on to the bark.

Fruit treatment

After fruit set, carry out spray treatments mainly focussed on single fruits using Carbosulfan, Malathion, Azinphos etc. mixed with a spreader/sticker liquid. Repeat applications at intervals of 2–3 weeks and combine this with the control of anthracnose.

The mango is usually attacked by three to four key pests which require annual control measures. However, there are a number of occasional pests which may become troublesome only in localized areas or because of the occurrence of unusual circumstances. These pests include mites, thrips, scales, cecid fly and mealybugs.

Powdery Mildew

The disease powdery mildew, caused by the fungus Oidium mangiferae, is a serious problem in all mango-growing areas in Kenya. Infections can result in complete crop loss and defoliation of trees. The disease favours cool and cloudy weather but also occurs in warm and humid climatic conditions. It attacks leaves, buds, flowers and young fruits. Infected tissues are covered with a whitish, powdery growth of the fungus. Mature spores are easily blown away by wind and produce a fresh infection, or they may remain dormant during the unfavourable season awaiting optimum germination conditions in the next season. Spraying 3–5 times at 10–14 day intervals from the onset of flowering until fruit set can control powdery mildew. Several chemicals are recommended and have been used to control the disease. These include Benomyl, Pyrazophos, Triadimefon, Bupirimate, Triforine and sulphur, all mixed with a spreader/sticker.

Cultivars treated for powdery mildew in this way show remarkable increases in fruit set ranging from about 40% to more than 500%. The input costs of the spray applied per tree are justified as they are recovered fully by increased returns.

Finally, as already mentioned, all mango cultivars are susceptible to powdery mildew infestation to some extent. The range of resistance (with Sensation being the most resistant) could be: Sensation, Chino, van Dyke, Tommy Atkins, Sabine, Kent, Keitt, Gesine, Batawi, Apple, Ngowe, Haden, Maya.

 

Description of Mango Cultivars

Alphonso

Also known as Appus, Badami, Gundu and Khader. This cultivar originated in Maharashtra State (India).

The fruits are orange-yellow in colour, medium-sized and oval/oblique in shape. They average 11.6 cm in length, 9.3 cm in width, and weigh 300–450 g (mean: 390 g). The skin is thin and smooth. The flesh is firm to soft, low in fibre, yellow, sweet, has a pleasant taste and is of good eating quality. The seed is mono-embryonic in a large, woody stone. The fruit matures in early to mid-season.

 

The tree is moderately large and vigorous with a broadly rounded dense canopy. It tends to have irregular bearing, but otherwise yields are medium to heavy.

Advantages:

  • excellent fruit quality
  • early and heavy cropper
  • moderate tree size

Disadvantages:

    • tendency towards biennial cropping
    • large seed
    • skin colour
    • susceptible to anthracnose

Apple

This cultivar originated from the Kenya coastline, most probably around the Malindi area. It is a chance seedling and its parentage is unknown.

The fruits are medium to large, nearly round in shape and have a rich yellow/orange to red colour when ripe. Average length measures 9.7 cm by 11 cm in width, and the weight is 280–580 g (mean: 397 g). Normally, if not diseased, the skin is smooth and thin, and the juicy yellow flesh is of excellent flavour and of melting texture virtually free from fibre. This is not a polyembryonic cultivar and trees propagated by seed are very heterogeneous in fruit shape, colour and quality.

 

The trees are large/vigorous and of pyriform growth habit. Depending on location, harvesting seasons are from December to the beginning of March; the yields are medium.

Advantages:

  • early cultivar of excellent fruit quality
  • small/medium seed size
  • free from fibres

Disadvantages:

  • susceptible to anthracnose and powdery mildew
  • alternate bearing
  • range of altitude adaptation is limited

Arumanis

This cultivar is also referred to as Harumanis and it originated from Indonesia. It is widely planted in humid parts of the world where many cultivars of better quality fail to fruit.

The small, oval to oblong fruits are yellow with large yellow-white dots and a rounded base. On average they are 8.3 cm long and 6.3 cm broad and weigh 95–190 g at Mwea in Central Province. The beak is inconspicuous and the skin is thin and tough. The flesh is firm and juicy with little fibre. It is lemon yellow, sweet, slightly insipid with a strong aroma, but with only poor to fair eating quality. The polyembryonic seed is covered in a thick woody shell.

 

The tree is vigorous and tall with a slightly open canopy. It bears in January but there is a tendency towards low yields and biennial bearing. Resistance to powdery mildew and anthracnose is only low to fair.

The cultivar has not adapted well at an altitude of about 1080 m in Mwea and should be tried in other agroclimatic zones to achieve better results.

Batawi

This mid-season cultivar was discovered in the eastern part of Kenya and its parentage is unknown. Propagation and planting have only been done on a limited scale.

Among the unimproved local cultivars this fruit might be classified fourth in quality after Apple, Ngowe and Boribo. The fruit is very large, round and has a rich olive-green to purple-maroon colour. Average length measures 10.7 cm by 10.6 cm in width and weight ranges from 470 to 590 g (average: 523 g). The internal quality is usually good both in texture—with little fibre—and in flavour. Fruits show a prominent beak and the flesh is pale orange.

 

The trees are relatively small, round in shape and bear a medium-sized crop. Maturity season starts in mid-January and ends in March.

Advantages:

  • seed propagation possible (polyembryonic)
  • resistance to anthracnose rather good
  • little fibre, no distinct biennial bearing

Disadvantages:

  • very susceptible to powdery mildew
  • undesirably large fruits
  • only fair productivity

Boribo

This cultivar also originated from a chance seedling found at the Kenya coast. The tree is grown extensively in the Malindi area.

The fruit is large and oblong but not as slender as Ngowe. The shoulders are only slightly curved, and the beak is obscure. The average fruit dimensions are: 11.5 cm long by 7.8 cm broad with a weight range of 430–640 g (mean: 511 g). The fruits are pale olive green with bloom and yellow-apricot when ripe. The internal fruit quality is good to excellent; the flesh is of a deep orange colour, virtually free from fibre, juicy, and of a very strong typical mango flavour. Propagation by seed is possible.

 

The tree is large and vigorous, and the picking season covers the months of January to February. There is no alternate bearing and the yields are medium to heavy.

Advantages:

  • seed propagation possible (polyembryonic)
  • regular bearing
  • fairly anthracnose resistant

Disadvantages:

  • susceptible to powdery mildew
  • flavour not liked by everybody
  • tree size

Carabao

This early mid-season cultivar originates from the Philippines where it is grown on a large scale for both local consumption and export. Since the seed is polyembryonic, propagation is easily done.

The medium-sized oblong to elongated and light green to yellow fruits are blushed with few small green dots (lenticels); the base is rounded to slightly flattened. The average dimensions are 13 cm long by 7.5 cm wide with weight ranging between 220 and 311 g. The skin is thin and medium-tough. The flesh is tender and melting with only a few fibres, lemon yellow, spicy and sweet with good to excellent eating quality. The fruits are produced in clusters.

 

The tree is vigorous, forming a large and dense canopy. It is a medium to heavy bearer but may alternate. Very good resistance to diseases has been recorded.

Advantages:

  • seed propagation possible (polyembryonic)
  • good yields and excellent quality
  • fair/good resistance to anthracnose and powdery mildew

Disadvantages:

  • skin colour
  • susceptible to fruit fly
  • may alternate in bearing fruit

Chino

The provenance of this mid-season cultivar is not known and it will never achieve commercial significance. However, trees produce abundant fruits of good quality and are recommended for backyard planting. Since the seed is polyembryonic, multiplication of true-to-type progeny does not pose any problems.

The medium-sized oblique and plump fruit has a greenish-orange colour often combined with a light red flush. The average fruit dimensions are: length 10.9 cm by 9.5 cm width; weight 386 g (range: 195–490 g). The base is rounded and there is an indication of a tiny beak. Lenticels are few, brown and corky. The yellow flesh is firm, spicy and juicy with only a moderate amount of fibre.

 

The tree is moderately vigorous, small to medium with a dense rounded canopy. Production (January–February) is heavy and regular, but the cultivar is highly susceptible to anthracnose.

Advantages:

  • seed propagation possible (polyembryonic)
  • small tree, but a heavy producer
  • fair resistance to powdery mildew

Disadvantages:

  • fruit lacks eye-appeal
  • very susceptible to anthracnose
  • the fruits do not store well on the tree

Dodo

This chance seedling must have been grown along the Kenya coast for a long time. Very old and huge trees can be found spread around the Kilifi-Malindi-Lamu area. Its parentage is unknown.

The fruit is large and fairly oval and ripens from dark green to a light green and finally turns yellow. The rounded and obvious beak faces downwards. The flesh is orange and juicy, the fibre content varies from little to much and there is usually a strong turpentine flavour. Lenticels are plenty, first green and later changing to brownish. The average dimensions are: length 11.6 cm by 9.9 cm in width, weight 453 g (range: 339–500 g). The seeds are polyembryonic and the fruit may be classified as one of the best of the more common local cultivars.

 

The tree is very large and of a tall, upright growth with dense foliage and small leaves. It is an alternate bearer but produces a considerable crop in productive years. Fruits mature in January and February and show a very good resistance to anthracnose.

Advantages:

  • seed propagation possible (polyembryonic)
  • good resistance to anthracnose
  • travels well to the market

Disadvantages:

  • huge tree and therefore difficult to harvest
  • tendency towards biennial bearing
  • susceptible to powdery mildew

 

Gesine

This early season (late December to mid-February) chance seedling is of unknown origin. To date trees are only grown in Central Province (Mwea, Maranjau, Ruiru) and may perform even better at lower altitudes.

The medium-sized, oblong brightly coloured fruit is of very good quality. Fruits exposed to the sun are of an intensive red colour, while those developing inside the canopy are apricot with a reddish blush. The fruit flesh is melting, juicy, deep orange, aromatic and relatively free from fibres. The average fruit dimensions are: length 11.7 cm by 7.8 cm width and an average weight of 280 g (range: 240–300 g). Lenticels are white changing to brownish-green at maturity. Without treatment the fruit is heavily attacked by anthracnose and to a lesser degree by powdery mildew.

 

The tree is medium in size and forms a dense canopy. Yields are heavy and regular.

Advantages:

  • very attractive fruits of good quality
  • crop early and consistently
  • small- to medium-sized tree

Disadvantages:

  • very susceptible to anthracnose
  • fruits do not store well on the tree

Golek

This cultivar originates from Indonesia and was released and planted in 1981 at Mwea in Central Province.

The mid-season fruit is greenish-yellow with an orange overlay and prominent white dots; it is oblong with a rounded base. The average fruit dimensions are: length 10.9 cm by 8.3 cm width and an average weight of 325 g (range: 210–500 g). The skin is thin and easily separated; the flesh is soft and juicy with abundant fibre (not objectionable), deep yellow, sweet, insipid with a mild aroma and a fair eating quality.

 

The tree is moderately vigorous with an upright, open canopy.

Advantages:

  • seed propagation possible (polyembryonic)
  • good resistance to anthracnose
  • good shipper

Disadvantages:

  • fruit colour
  • flavour not very popular
  • needs more publicity

 

Haden

This seedling of Mulgoba (Indian type) originating from Florida was introduced in 1910 and has since been grown in numerous other countries. Because of its excellent quality, the seed is used as parent for several other cultivars.

The medium to large-sized fruit is bright yellow with deep crimson or red blush and numerous large whitish/yellow glands. The shape is regular ovate and plump with a rounded base and depressed beak. Average length is 10 cm with an 8 cm width and an average weight of 431 g. The skin is thick and tough; the flesh is yellowish-orange, firm, very juicy with a pleasant aroma. Moderate fibre occurs only close to the seed which is mono-embryonic and covered in a medium-thick woody shell. This outstanding cultivar is harvested around January to late February.

 

The tree becomes quite large and spreading; production is erratic but yields are satisfactory.

Advantages:

    • very attractive appearance
    • excellent fruit quality
    • suitable for commercial plantings
    • good shipper

Disadvantages:

    • susceptible to anthracnose and only moderately resistant to powdery mildew; increased inputs are therefore needed to produce clean fruits

Heart

This cultivar is a new introduction into Kenya which was released in 1980 and planted around Mwea and Malindi. Mainly because of its relatively unattractive colour, this Indochinese cultivar will never attain any commercial importance in Kenya.

The fruit is small to medium sized and of a bright yellow colour with a few large white dots. It is heart-shaped with a flattened base and beak. It has an average length of 8.4 cm, is 8 cm wide and its weight ranges from 140 to 255 g. The skin is thick. The flesh is firm and juicy with a moderate amount of coarse fibres; it is lemon yellow and has a spicy, resinous aroma. Its eating quality is only fair.

 

The tree is vigorous with a large, spreading rounded canopy. This mid-season cultivar is a fairly good and regular producer.

Advantages:

  • seed propagation possible (polyembryonic)
  • no distinct biennial bearing
  • resistance to anthracnose is rather good

Disadvantages:

  • flavour not very popular among consumers
  • colour of skin
  • size of fruit

Irwin

As a seedling of Lippens, this cultivar originated in Miami (1945) and has been Florida��s leading local market cultivar for a long time.

The fruit is bright yellow with a crimson or dark red blush and numerous large white dots. Its shape is ovate with a rounded base; average size is 12.3 cm long and 8.5 cm wide; average weight is 372 g. Fruits are often produced in clusters. The flesh is soft, tender, melting and juicy; only slightly fibrous, lemon yellow, sweet and mild with a pleasant aroma and of good quality. The seed is mono-embryonic and embedded in a relatively small and thin stone shell.

 

The tree is small to medium, moderately vigorous with an open canopy and produces consistently good yields. The fruits mature from late January until March (mid-season).

Advantages:

  • good fruit quality combined with attractive appearance
  • one of the most prolific cultivars
  • trees are somewhat dwarf-sized

Disadvantages:

  • short post-harvest life

Keitt

This open pollinated seedling of Mulgoba originated from Homestead (Florida) and was released in 1946.

It is one of the latest maturing of all the recommended cultivars. It has an exceptional keeping quality and may be left on the trees long after the normal harvesting time (March–April). The fruit is large with an average length of 11.7 cm and a width of 9.2 cm; it has an average weight of 456 g. It has a greenish-yellow colour with pink or red blush and lavender bloom. There are numerous white or yellow/red lenticels on the thick and fairly tough skin. The fruit shape is ovate and plump without a beak; it has a rounded base. The flesh is deep yellow, fairly firm but tender, melting, juicy and with only a little fibre near the seed. The flavour is rich and sweet with a pleasant aroma and excellent quality. The fairly small seed (7.5% of fruit weight) is mono-embryonic.

 

The tree is medium-sized, moderately vigorous, producing long arching branches and has a scraggy open appearance. It is a heavy and regular bearer.

Advantages:

  • a cultivar with late maturity
  • good marketing qualities and productivity
  • fair resistance to anthracnose

Disadvantages:

  • skin coloration often inadequate
  • highly susceptible to bacterial black spot and affected by internal breakdown of the flesh (reported from Australia)
  • susceptible to sunburn

Kensington

This seedling originated from Queensland, Australia (1960s), and is also known as Kensington pride and Bowen. In the 1980s, this cultivar was released and planted at Mwea (Central Province).

At present, this early mid-season cultivar enjoys only little attention but shows great potential especially for the local market. The fruit is medium in size, almost round with a flattened base and a slight beak, averaging 12.2 cm in length and 8.1 cm in width; average weight is 319 g. When ripe, the skin colour is yellow with a slightly orange/pink blush.

The skin is thick and adherent and the flesh yellow, sweet, soft and juicy with moderate to little fibre. The seed, covered by a moderately thick woody stone (7.8% of fruit weight) is polyembryonic.

 

The trees are vigorous/spreading and produce consistent, high yields.

Advantages:

  • propagation by both seed (polyembryonic) and grafting
  • good shelf life
  • excellent eating quality

Disadvantages:

  • moderately susceptible to anthracnose
  • needs more publicity

Kent

This open pollinated seedling of the cultivar Brooks originated in Miami, Florida, and was released in 1944.

Kent is often mistaken for the quite similar looking cultivar Keitt but (just one difference) Kent matures earlier (March). The large fruit is greenish-yellow with a red or crimson blush on the shoulder. The average length measures 12.4 cm with a width of 9.7 cm and an average weight of 545 g. The fruit-shape is regular ovate with a rounded base and often with two slight beaks. The skin is thick and tough and small yellow lenticels are numerous; the flesh is juicy, melting, deep yellow, fibreless and of a rich flavour. The seed, embedded in a thick, woody stone (8.5% of fruit weight) is mono-embryonic.

 

The tree is large and vigorous, with a dense upright canopy, and it produces good yields in the late mid-season.

Advantages:

  • late maturity
  • fibreless and of excellent internal quality
  • fruits ship well

Disadvantages:

  • skin coloration is often inadequate
  • prone to storage diseases
  • may alternate in bearing

Madoe

This cultivar originated from Indonesia where it is also known as Madu. In Kenya, the cultivar was released and planted in 1981 at Mwea (Central Province), among other locations.

The fruits resemble the local Apple cultivar but are much more resistant to anthracnose. They are medium to large in size, oval/oblique in shape with a rounded base and a slight beak. The average length measures 9.7 cm with a width of 10.7 cm, and the weight varies from 310–450 g (mean: 380 g). The skin colour is deep yellow/apricot with the shoulders showing a reddish flush. The yellow flesh is soft, tender and juicy, almost fibreless and of rich flavour.

 

The tree is moderately vigorous with a dense, rounded canopy.

It produces medium-heavy yields during mid-season and has a polyembryonic seed.

Advantages:

  • good anthracnose resistance
  • outstanding fruit quality
  • seed propagation is possible (polyembryonic)

Disadvantage:

  • not much known on the local market

Matthias

This mid-season (January to mid-February), open pollinated chance seedling is of unknown origin but comes most probably from West Africa. In Kenya, the single mother tree—propagated by seed—was found in Trans Nzoia District. Progeny was later transferred into Central Province (Mwea, Ruiru).

The medium-sized ovate fruit has a deep-yellow skin and its shoulders are blushed with red. There is only a slight beak; lenticels are at first green and later turn yellow. The average fruit dimensions are: length 10.3 cm and width 7.8 cm, with an average weight of 251 g. The firm yellow flesh is sweet, juicy and relatively free from fibres. There is a moderate resistance to anthracnose and powdery mildew.

 

The tree is of medium to large size and forms a dense canopy. Yields are heavy and regular.

Advantages:

  • moderate resistance to anthracnose and powdery mildew
  • propagation by both seed (polyembryonic) and grafting
  • regular bearer

Disadvantage:

  • more adaptation trials and more publicity are needed

Maya

A cultivar of unknown parentage (Haden X?), Maya was selected in Israel and very much resembles the Haden cultivar although its fruits are much smaller.

The ovate and plump fruit is yellow with a reddish blush and is medium-sized. The average fruit length measures 10.3 cm with a width of 7.8 cm, and the weight ranges from 250–380 g (mean: 295 g). There is only a small rounded beak. Lenticels are white at first, changing to yellow/brown later. The firm yellow flesh is juicy and aromatic, virtually free from fibre and of high eating quality. The fairly large seed (9.2% of fruit weight) is mono-embryonic.

 

The tree is large and vigorous, tends to alternate bearing and is very susceptible to anthracnose.

Advantages:

  • resembles Haden
  • good to excellent eating quality

Disadvantages:

  • highly susceptible to anthracnose
  • danger of internal breakdown of fruit flesh

Ngowe

The original Ngowe tree (so it is believed) was brought from Zanzibar and planted on Lamu approximately 106 years ago. This typical coastal cultivar, also known as Lamu mango, can now be found all along the coastline and has also adapted well to medium altitude locations.

Ngowe is the most easily recognized of the local mango fruits. It is large, oblong and slender with a very prominent hook-like beak at the apex. From pale green, the fruit develops to a most attractive yellow to orange colour when ripe. The deep yellow flesh is of excellent quality, virtually free from fibre, melting, and carries no turpentine taste. The average fruit length measures 14 cm with a width of 9.5 cm, and a weight range of 425–600 g (mean: 523 g). The seeds are polyembryonic which means progeny develops more or less true-to-type.

 

The trees are comparatively small and round in shape. Depending on location, harvesting may start in November and continue until March. Yields are medium and alternate bearing may occur.

Advantages:

  • good to excellent fruit quality
  • moderate tree size
  • good shipper
  • seed propagation possible (polyembryonic)

Disadvantages:

  • susceptible to powdery mildew
  • tendency of alternate bearing

 

Nimrod

This cultivar originated from Israel and more or less resembles the Apple cultivar found in Kenya.

The large oval/oblique fruit is deep yellow with a light red flush and numerous yellow lenticels when ripe. The base is flattened and there is only a slight indication of a small rounded beak. The average fruit length measures 11 cm with a width of 10 cm, and the weight ranges from 340–580 g. The skin is thick and tough and separates easily; the flesh is soft and juicy with little fibre, yellow, mild, aromatic and of good eating quality. The seed is mono-embryonic and embedded in a medium-thick woody stone (7.6% of fruit weight).

 

The tree is vigorous, medium-sized, with an upright dense canopy. Harvesting in Central Province starts at the end of December and ends in January.

Comments:

  • Since this cultivar is quite a recent introduction, more field research is required before final recommendations can be compiled. Already there are indications that if planted in the proper environment (at least below 800 m) it may do even better than the Apple cultivar.

 

Parwin

This seedling originated from Bradenton in Florida and was released in 1954. Of unknown parentage, it resembles Haden but lacks the latter��s bright red colour.

The fruit is medium to large with an average length of 10.8 cm and a width of 8.5 cm. The average weight is 470 g (range: 380–560 g). The shape is oblong to ovate and tends to be plump; the basic colour is light yellow with a pink/red blush; lenticels are distinct and numerous. The fruits are often borne in clusters. The yellow juicy flesh is relatively free from fibres, moderately sweet with a good flavour. The medium-sized stone (7.5% of fruit weight) covers the mono-embryonic seed.

 

The tree is vigorous with a slightly open habit and there is a remarkable resistance to anthracnose and powdery mildew. Yields are satisfactory and quite regular.

Comments:

  • A very promising new cultivar in Kenya. Since the fruits have a very long storage life, are harvested in late mid-season and are of good quality, planting this cultivar should be encouraged.

Peach

By 1928, this seedling of unknown origin was already described in South Africa where it was ranked as one of the best local unimproved cultivars.

The roundish/oblique medium-sized fruits are fibrous. The average size is 9.3 cm long and 8.1 cm wide with an average weight of 241 g. The apex is broadly rounded with a depression on the ventral side and a slight beak. The thick tough skin is smooth with white lenticels and has an attractive yellow-orange colour. The flesh is apricot-yellow with a tender juicy texture. The eating quality is good; there is a sweet flavour and a very slight turpentine taste. The seed is large (8.1% of fruit weight) and polyembryonic.

 

The trees are big and produce consistent high yields. The maturity season starts at the end of December and continues until February.

Advantages:

  • fairly resistant to diseases
  • good shelf life
  • suitable for higher elevations

Disadvantages:

  • only suitable for the local market
  • contains a rather high amount of fibre

Sabine

In 1969, the author found this chance seedling on the Bowker farm in Trans Nzoia District, Kenya. Due to high altitude (about 1900 m) the fruit-set and quality were very poor. Scion material was later transferred into lower and warmer locations (Central Province) where it developed into a highly demanded cultivar.

The medium- to large-sized, elongated but full fruits are of very good quality. Those developing inside the canopy are deep yellow while those exposed to the sun are bright yellow with a dark red blush. The yellow flesh is of medium texture, fibreless, pleasantly sweet, juicy and of a mild aroma. The average fruit dimensions are: length 14.2 cm, width 6.6 cm and weight 435 g (range: 360–520 g). The rounded apex carries only a small depressed beak. The seed is mono-embryonic and covered by a medium-sized woody stone (9.6% of fruit weight). There are indications that this cultivar may also be multiplied by seed.

 

The tree is moderately vigorous and upright with a dense canopy. There seems to be a slight alternation in bearing but yields are satisfactory. Depending on location, fruits mature from late January until late March.

Advantages:

  • only slightly affected by anthracnose and powdery mildew
  • no distinct biennial bearing
  • no fibres

Disadvantages:

  • needs more publicity

Sabre

Most probably, this cultivar has its origin in South Africa; already in 1928 it had been described by Davis and in 1947 it was one of the most widely planted cultivars. Besides its fair eating quality, Sabre as a polyembryonic seed producer is better known as a rootstock supplier.

In Kenya, the oblong, kidney-shaped fruits are small to medium sized. On average they are 11.8 cm long and 6.9 cm broad and weigh an average of 233 g (range: 180–290 g), the apex being broadly rounded and curved into a prominent beak. The smooth-surfaced tough leathery skin—yellow-green, often with a reddish blush—is easily removed from the flesh. The flesh is deep orange in colour with a melting texture and a medium amount of fibre. The eating quality is fair, sweet to insipid-flavoured and normally has a turpentine aftertaste. The seed is large, up to 9.4% of total fruit weight.

 

The tree is small to medium, a regular and heavy bearer and fairly resistant to diseases. The maturity season starts in late December and ends at the beginning of March.

Advantages:

  • suitable for higher elevations
  • fairly good resistance to anthracnose and powdery mildew
  • recommended rootstock producer

Disadvantages:

  • fruit quality in general
  • over-bearing

Sensation

This cultivar originates from Miami, Florida, and was released in 1941.

The oval/oblique, medium-sized fruit is deep yellow with a prominent dark-red to purple blush that covers most of its surface. The rounded apex shows only a slight beak formation. The average fruit measurements are: length 10.8 cm by 7.8 cm in width and an average of 307 g in weight. Lenticels are numerous and pale yellow in colour; the skin is medium-thick, tough and separates easily from the flesh. The deep-yellow flesh is fibreless, firm and juicy. It is sweet, of a distinctive mild flavour and of good quality. The mono-embryonic seed is covered in a thick woody stone (5.8% of fruit weight). Due to its severely alternate bearing, susceptibility to anthracnose and uneven ripening, Sensation has lost much of its former popularity.

 

The trees are moderately vigorous and develop into a broad-rounded, symmetrical canopy. It is a late cultivar and, depending on location, will mature from February until the beginning of April.

Advantages:

  • beautifully coloured late cultivar
  • none to scanty fibres
  • heavy yielder

Disadvantages:

  • susceptibility to anthracnose
  • alternate bearing
  • frequent severe internal breakdown (jelly seed)

Smith

This open pollinated seedling of Haden was found growing on the J.T. Smith farm in Honolulu, Hawaii, and was introduced to Florida around 1946.

The elongated large fruits are of an orange-yellow base colour combined with a deep crimson blush. The apex is broadly rounded and there is no beak. The thick tough skin is covered with large white lenticels. The average fruit size is 13.9 cm long and 7.5 cm wide, with an average weight of 550 g. The orange-yellow flesh is juicy, spicy, of a firm texture and almost fibreless. The fruit quality is rated as good and yields are moderate to heavy and regular. The seed is fairly large (7% of fruit weight), long, flat and mono-embryonic.

 

The trees grow upright and vigorously and are harvested at mid-season. Fruits must be left on the tree to maturity if they are to develop their full colour and flavour.

Advantages:

  • highly productive
  • nearly fibreless
  • good coloration

Disadvantages:

  • quite susceptible to anthracnose
  • tendency to only fair fruit quality

Tommy Atkins

This cultivar originated from a seed planted in the 1920s at Fort Lauderdale in Florida. Parentage is unknown (Haden seedling?); it was released in 1948.

Tommy Atkins has become an important commercial variety. The fruits are medium to large, oval to oblong, orange/yellow with a heavy red blush, numerous white lenticels and a broadly rounded base. They measure an average length of 12.6 cm, are 9.9 cm wide and have an average weight of 522 g. The smooth skin is tough and thick. The flesh is firm and medium juicy with a moderate amount of fibre, yellow to deep yellow in colour, mild and sweet with a strong pleasant aroma. The eating quality is fairly good; the seed is mono-embryonic and covered in a thick, woody stone (6.6% of total fruit weight).

 

The tree is vigorous/large with a rounded canopy and it produces consistently heavy and good crops. It is an early to mid-season cultivar and is highly resistant to diseases.

Advantages:

  • very attractive fruits
  • excellent shipping and shelf-life qualities
  • consistent producer
  • good resistance to anthracnose and powdery mildew

Disadvantages:

  • danger of internal breakdown (jelly seed)
  • fibre content is slightly higher than average

Van Dyke

This cultivar originated from Homestead (Florida) and belongs to a selected group of seedlings distinguished by a greater resistance to anthracnose, very attractive colour, and good shelf life and shipping qualities. These seedlings appeared in the 1950s and 1960s.

The ovate, small- to medium-sized fruit (average weight 280 g) is very attractive showing a bright yellow ground colour with a heavy crimson blush and prominent beak. The average fruit dimensions are: 10.5 cm length by 7.9 cm width. The skin is thick, though easily separating and covered with numerous white/yellow lenticels. The flesh is quite firm, melting and juicy with little fibre, orange-yellow, rich, spicy and sweet with a strong pleasant aroma. It is of good to excellent quality. The seed is mono-embryonic and covered by a medium-sized woody stone (7.1% of fruit weight).

 

The trees are medium-sized with a large open canopy and are regular producers but yield only moderately.

Advantages:

  • attractive colour
  • good resistance to anthracnose and powdery mildew
  • regular bearer

Disadvantages:

  • poor to moderate yields
  • fruit size

Zill

As a Haden seedling it originated in Lake Worth, Florida, in 1930.

The small to medium, ovate fruit is yellow with an intense red or crimson blush. The apex is rounded with a small beak. The fruit shape resembles that of van Dyke, and the average dimensions are: length 10.6 cm by 8.2 cm width, average weight 285 g (range: 225–345 g). Lenticels are yellow/brown and the flesh is deep yellow, juicy, soft and without fibre. The flavour is rich and sweet and of good to excellent eating quality. The seed is mono-embryonic and covered by a thick woody stone (8% of fruit weight).

 

The tree becomes fairly large with an open, spreading canopy. This early to mid-season cultivar produces well and fairly consistently. Zill has a moderate resistance to anthracnose and powdery mildew, but does not withstand storage and shipping stress well.

Advantages:

  • early season cultivar
  • regular producer
  • outstanding quality

Disadvantages:

  • not a good shipper
  • danger of internal breakdown (jelly seed)
  • low/moderate resistance to diseases

Zillate

Not much is known about the origin of this cultivar but it is assumed that the seedling was developed in Florida.

The medium-sized oblong fruit is of a yellow ground-colour and has an intensive red blush. There are numerous small white lenticels covering the thick, tough skin. The rounded apex carries an almost non-existent underdeveloped beak. The average fruit dimensions are: length 12.5 cm by 7.1 cm width, with a weight of 291 g (range: 260–350 g). The firm, juicy, yellow flesh is relatively free from fibre, aromatic and of good eating quality. The fairly large flat seed (7.8% of total fruit weight) is mono-embryonic.

 

The tree is moderately vigorous, forming an upright tight canopy. The rather late-season cultivar yields quite well and regularly. It shows moderate resistance to powdery mildew but is affected by anthracnose.

Advantages:

  • good shelf life
  • fibreless and of good eating quality
  • attractive appearance

Disadvantage:

  • needs more publicity

 

Further Reading

    1. Fintrac Consulting. 1989. Report for COLEACP. http:// www.coleacp.org/fo-internet/ en/welcome.html.
    2. FAO (Food and Agriculture Organization of the United Nations). 2001. FAOSTAT 2001 database. Rome, Italy: Food and Agriculture Organization of the United Nations. http://apps.fao.org/default.htm.
    3. Griesbach J. 1981. What you should know about mango growing. Kenya Farmer. Nairobi, Kenya: Agricultural Society of Kenya.
    4. Griesbach J. 1985. New mango types currently grown in Kenya. Kenya Farmer. Nairobi, Kenya: Agricultural Society of Kenya.
    5. Griesbach J. May 1989. Anthracnose: Pre-harvest treatment trial in mango. Unpublished trial results.
    6. Griesbach J. April 1991. Preventive control of powdery mildew on mango. Unpublished trial results.
    7. Griesbach J. July 1991. Mango seed weevil. Unpublished trial results.
    8. Griesbach J. September 1991. Control measures against mango anthracnose. Unpublished trial results.
    9. Griesbach J. 1992. A guide to propagation and cultivation of fruit trees in Kenya. Schriftenreihe der GTZ no. 230. Eschborn, Germany. 180 pp.
    10. Hill DS. 1983. Agricultural insect pests of the tropics and their control. Cambridge University Press.
    11. Jaetzold R. and Schmidt H. 1983. Farm management handbook of Kenya. Volumes A, B, and C. Nairobi, Kenya: Ministry of Agriculture, Nairobi, Kenya/Germany: German Agency for Technical Cooperation (GTZ)
    12. Knight RJ (Jr.). 1997. Important mango cultivars and their descriptors. Homestead, Florida, USA: Tropical Research and Education Center, University of Florida.
    13. Mabberly DJ. 1997. The plant book. Cambridge, UK: Cambridge University Press.
    14. Mervyn von L. 2000. Thorsons�� complete guide to vitamins and minerals for your health. Harper Collins
    15. Ministry of Agriculture. 2001. Annual report 2000. Nairobi, Kenya: Ministry of Agriculture.
    16. Ministry of Agriculture. 2002. Horticulture annual report 2001. Nairobi, Kenya: Ministry of Agriculture.
    17. Page PE. 1984. Tropical tree fruits for Australia. . Brisbane, Queensland, Australia: Queensland Department of Primary Industries.
    18. Platt BS. 1962. The composition of selected fruits. MRC Special Report no. 302. London, UK: HMSO.
    19. Salim AS, Simons AJ, Orwa C, Chege J, Owuor B and Mutua A. 2002. Agroforestree database: a tree species reference and selection guide. Version 2.0 CD-ROM. Nairobi, Kenya: International Centre for Research in Agroforestry.
    20. Samson JA. 1980. Tropical fruits. Tropical Agriculture Series. Longman Group Limited.
    21. Yee W. 1958. The mango in Hawaii. Hawaii, USA: College of Tropical Agriculture, University of Hawaii.
    22. Young TW and Sauls JW. 1979. The mango industry in Florida. Florida, USA.

 

Contributors

Author - Juergen Griesbach, ICRAF

RoboHelp Development for the Internet, CD-ROM, and Print - Albert Dean Atkinson, IRRI

 

Glossary

A

    acaracide: material toxic to mites

    acid soil: pH less than 7.0

    active ingredient: toxic component of a formulated pesticide

    adhesive = sticker: material added to increase pesticide retention

    alkaline soil: pH greater than 7.0

    anther: the pollen-bearing part of a stamen

    apex: tip of shoot

    attractant: material with an odour that attracts certain insects

B

    bait: foodstuff used for attracting pests, usually mixed with a poison

    beak: a pointed projection at the tip of a fruit

    biological control: control of pests by disease-producing organisms, preditors, or parasites

    bloom: the delicate waxy or powdery substance on the surface of berries

C

    calyx: the external part of a flowers consisting of sepals

    canopy: crown of a plant

    carrier: material serving as diluent for the active ingredients

    clone: identical individuals propagated vegetatively from a single plant

    compatibility: ability of the scion and stock to unite in grafting and form a strong union

    contact poison: material killing pests by contact action

    control: untreated subjects used for comparison with those given a particular treatment

    cotyledons: the primary leaves of germinating plants

    culling: discarding of plants that do not meet requirements

    cultivar: variety, type

D

    discard: active during daytime

    dormant: alive but not growing; a resting stage

E

    elongated: longer than it is broad

    embryo: part of a seed which will grow into a plant

    eradicate: destroy, extirpate

F

    fertilization: pollination

    fungicide: chemical to control plant diseases

G

    gall: abnormal growth of plant tissues

    genus: a group of plants comprising a number of closely related species

    germplasm: any plant part used for regeneration

    grafting: joining parts of plants together such that they will unite and continue their growth as one plant

H

    herbicide: any chemical used to kill plants

    husk: a stringy shell of a seed

I

    immature: unripe, not ready

    indigenous: a plant native to the region

    inflorescence: the flowering part of a plant

    insecticide: chemical to control crop pests

    intercropping: the growing of two crops simultaneously in the same field

L

    latent: dormant

    latex: milky plant juice

    lenticel: a pore like, slightly raised spot on a fruit skin

M

    maggot: a vermiform, legless larva (Diptera)

    maturity: stage of final fruit development (ripeness)

    mono-embryonic: mode of reproduction: contains only one embryo

N

    nocturnal: active at night

O

    oblong: longer than broad

    oviparous: reproduction by laying eggs

P

    panicle: a loosely branched inflorescence

    pedical: the stalk of one flower in a cluster

    perfect flower: a flower having both stamens and pistil

    persistence: chemicals that remain active for a long period of time after application

    pest: an animal or plant causing damage to crops

    pesticide: a chemical which by virtue of its toxicity is used to kill pest organisms

    pH value: refers to degree of acidity or alkalinity as a scale of numbers from 1 (very acid) to 14 (very alkaline)

    phytotoxic: a chemical liable to damage or kill plants

    pistel: the female part of the flower

    pollination: the transfer of pollen from the anther to the stigma

    polyembryonic: mode for reproduction: contains more than one embryo; produces true-to-type progeny

    progeny: a plant��s ��offspring��

    propagate: multiplication of more plants

    provenance: germplasm from a single place of origin

Q

    quarantine: the prevention of importation or exportation of unwanted organisms into a territory

R

    repellant: a chemical which has the property of inducing avoidance by a particular pest

    residue: amount of pesticide remaining in or on plant tissues after a given time

    rootstock: plants propagated for further grafting/budding

S

    scion: the plant part grafted onto the stock

    self-fertile: fertilization without cross pollination

    stalk: also called peduncle

    stamen: the pollen-producing organ of a flower

    sterile: flowers not capable of producing viable seed

    sticker: material added to a spray to increase retention on plant foliage

    surfactant: a chemical which modifies the surface tension of spray droplets

    susceptible: not resistant

    systemic: an insecticide absorbed by plants and translocated throughout

T

    terminal: borne at the end of a stem

    tissue: plant cells

    tolerance: maximum amount of toxicant allowed in foodstuffs for human consumption

    top-working: converting a grown tree by grafting

    trunk: the main stem of a tree

V

    variety: a group of closely related plants of common origin

 

Index

 


 

 

 

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