|
|
|
|
 |
 |
|
|
|
|
Green-seeds.com:
publications & research: articles
|
|
|
|
PRESENT STATUS OF HORTICULTURE RESEARCH IN SRI LANKA
C. Kudagamage
Ph.D.
Deputy Director (Research)
Horticultural Crop Research & Development Institute
Gannoruwa, Peradeniya
SRI LANKA.
|
Introduction
Physical and Climatic features of the country
 Sri Lanka is an
Island located between 6 and 10 north of equator at the southern tip
of the indian sub-continent. It has a total area of 6.56m ha and three
climatic zones could be recognized; a wet zone of 1.54 m ha in the
south west quadrant, a dry zone of 4.17 m ha enclosing the bulk of
the island in the north, east, north west and south east, and an intermediate
zone of 0.85 m ha between the wet and dry zone (Figure 1). The three
climatic zones are divided into seven agro ecological zones by altitude
and land form (Table 1).
Although the wet
and intermediate zones range from low country (0-300 m above sea level)
and mid country (300-900 m) to up country (above 900 m) the vast expance
of the dry zone is exclusively in the low country. The land form of
the low country varies from flat to undulating while the mid and up
country varies from undulating, rolling, hilly and steeply dissected
to mountains. These seven zones are further sub divided into 22 well
defined agro-ecological regions, each with its unique pattern of rainfall,
elevation, land form, temperature range and soil type.
In Sri Lanka the
most important weather parameter that has the greatest impact on Agriculture
is the rainfall. The country is under the influence of two monsoons
namely south-west and north-east, which occur alternatively bringing
rain to south west part and north east part of the Island respectively.
These two monsoon as they blow over the Island are intercepted by
central highlands, consequently the leeward side is subjected to scorching
winds causing a dry spell. In addition, conventional rain occur during
intermonsoonal periods. Hence in most parts of the country rain fall
follows a bi-modal pattern leading to a main cropping season called
Maha (Oct.- Jan.) and a minor cropping season called Yala
(March-July). As can be expected with monsoon rain farmers are many
a time riddled with sufficiency and reliability of rainfall. Wetzone
receives higher rainfall throughout the year consequent upon higher
liability for soil erosion and nutrient leaching.
Rainfall in the
wetzone is adequate for year round cultivation of horticulture crops,
while in the intermediate and dry zone the rainfall is adequate for
crop growth only during Maha season. During Yala rainfall
should be supplemented with irrigation for satisfactory crop growth.
Table 1: Environmental parameters of major agroecological regions
|
Agroecological regions
|
Elevation (m)
|
Mean temperature (°C)
|
Rainfall (mm)
|
|
Wet zone
Up country
Mid country
Low country
|
1000-2000
500-1000
0-300
|
10-15
20-15
20-25
|
2500-5000
2000-3000
2000-3000
|
|
Intermediate zone
Up country
Mid country
Low country
|
1000-1500
350-500
0-300
|
15-22
24-26
25-29
|
1500-2250
1500-2250
2000-2200
|
|
Dry zone
Low country
|
0-300
|
28-30
|
900-1000
|
Demography
South-west quadrant of the island is thickly populated while in the
dryzone more land is still available for farming. Land to man ratio
for the island work out to be 0.38 ha/man in 1991. This ratio keeps
on decreasing.
Production systems
Vegetables
Land holdings
of the areas where vegetables are cultivated are generally small ranging
from 0.09 to 0.37 ha in the dryzone and from 0.57 to 1.46 ha in the
wet zone.
Bulk of the country's
temperate type of vegetables are produced in the hilly areas of Nuwara
Eliya and Badulla districts (Figure 2) where a very high cropping
intensity is practised. Management is carried out at a exceptionally
higher standard. In these areas with a favourable climate and ample
supply of water, vegetables can be cultivated through out the year
(Figure 3). Many
kinds of exotic vegetables such as cabbage, beet root, knolkhol, leeks,
radish, carrot, lettuce are grown with high management practices.
However, potato and tea cultivation in the region makes the land availability
competitive for vegetable cultivation.
In many parts
of the dry and intermediate zones and certain areas of mid country
wet zone vegetables including onions are cultivated in paddy fields
during yala season. In the dryzone, this system is practised only
in areas where sufficient irrigation water is guaranteed ie. under
major irrigation schemes and agro wells. Chillies, capsicums, tomato,
brinjal, pumpkin, gourds, gherkin and onion are some common vegetables
grown in these areas. In the mid country different types of gourd,
tomato, knolkhol, okra, radish, capsicum, brinjal, cabbage, and beet
root are found to be more attractive.
Table 2: Common Leafy Vegetable and other fruit vegetables Crops
grown in Sri Lanka
| Botanical Name |
Local Name |
|
Leafy Vegetables
Centella asiatica
Amaranthus tricolor
Moringa oleifera
Sesbania gradiflora
Cycus circinalis
Basella alba
Alternanthera sessilis
Ipomoea aquatica
Brassia oleracea
Lactuca sativa
Trianthema decandra
Lasia spinesa
Fruit Vegetables
Lycopersicon esculentum
Capsicum annum
Momordica charantia
Luffa acutangula
Abelmoschus esculentus
Artocarpus altilis
Lagenaria siceraria
Musa sapientum
Solanum melongena
Phaseolus vulgaris
Trichosanthes anguina
Cucurbita maxima
Moringa oleifera
Artocarpus heterophyllus
Psophocarpus tetragonolobus
cucumis sativus
Root and Tubers
Beta vulgaris
Raphanus sativus
Ipomoea batatas
Coleus rotundifolius
Xanthosoma sagittifolium
Daucus carota
Solanum tuberosum
Manihot utilissima
Dioscorea alata
Lasia spinosa
Seeds
Cajanus cajan
Vigna unguiculta
Vigna radiata
Artocarpus altilis
|
Gotukola
Amaranthus
Drumstick
Kathurumurnga
Madukoku
Spinach
Mukunuwanna
Kankung
Cabbage
Lettuce
Sarana
Kohila
Tomato
Sweet/hot pepper
Bitter gourd
Luffa
Okra
Breadfruit
Bottle gourd
Ash plantain
Brinjal (eggplant)
Beans
Snake gourd
Pumpkin
Drumstick
Jak Jackfruit
Winged bean
Cucumber
Beetroot
Radish
Sweet potato
Innala
Tannia
Carrot
Potato
Manioc
Wellala
Kohilaala
Toor dhal
Cowpea
Mungbean
Jak(Bread fruit)
Beans
Soybean
|
Shifting cultivation
In the dryzone where traditional shifting cultivation is practised
where large extents of land 2-5 ha is cleaned and burned for cultivation
just before the Maha rain. Many kinds of indigenous vegetables
together with number of cereals, millets, legumes and root crops are
sown with the onset of rain. Among the common vegetables, chillies,
brinjal, gourds, cucumber, pumpkin, okra. takes prominence in the
system. It is very rare to find a monocrop in this system of farming
and crop intensity is very low and the use of inputs such as quality
seed and agrochemicals is minimal.
Leafy vegetable production
Leafy vegetables form an important part of the Sri Lankan diet. The
leafy vegetables (Table 2) are cultivated mainly in the wetter regions
or in areas where rainfall is not a limiting factor. Commercial scale
cultivation of this group of vegetables is seen near urban areas as
the produce find a ready market and transport is easy. They are easy
to grow, require low inputs and have relatively shorter growth periods,
thus making crop intensity high by cultivating throughout the year
with multiple harvests.
Home garden
The homegardens contribute in no small way to vegetable cultivation.
Almost every back yard of a house has several varieties of vegetables
grown which supply the day to day requirement of vegetable for domestic
consumption.
Fruits
Presently, fruit
cultivation is mainly found in the homegardens. It is customary for
Sri Lankans to plant an Orange, a Lime tree, a Mango plant and few
clumps of Banana around their homes. Home gardens form the most important
unit of production of fruits. Country's mango production solely comes
from Home gardens.
Fruit cultivation
in orchard scale per se is rarely seen in Sri Lanka except in the
coconut triangle where our most important fruit crops; Banana, Pineapple
Rambutan and Papaya are grown in extensive scale as intercrops. Longterm
experiments conducted by Rubber Research Institute of Sri Lanka has
clearly shown that Juvenile rubber plantation could be intercropped
with fruit crops like Passion fruit and Banana upto 6 years before
the canopy cover up. Wood apple groves are found near tanks (water
reservoirs) in the Dry Zone. Banana are grown in large scale in the
dryzone either lowlands near tanks or along river banks under irrigation.
Most of the fruit
cultivars grown in the country are found scattered in the wetzone
which is highly populated and almost all the land space suitable for
fruit cultivation is already utilized. However, emphasis should be
on orchard type cultivation, where ever possible. For this land is
available in the dry and intermediate zone of the country. The agro-climate
in these two zones is also ideally suited for fruits to develop it
appearance, colour and flavour. Production can be increased with supplementary
irrigation.
Present status of fruit and vegetable sector
The present average
extent under fruit crops is about 70,000 ha out of which 50% is under
banana. Annual production is about 600,000t of which about 50% is
locally consumed, 30-40% is wasted and about 10% is being exported
(Table 3).
Per capita availability
of fruits is estimated to range between 3.39 kg to 26 kg/person/year
according to different sources . The corresponding figures for vegetable
is about 33.76 kg/person/year. Per capita requirement of fruits and
vegetables based on nutritional needs are 40 kg/person/year and 75
kg/person/year respectively. Hence there is ample scope for the expansion
of horticulture sector just for domestic consumption alone.
From national
statistics available an estimated 700,00 mt. of vegetables are produced
annually in an area of 60,000 ha (Table 4).
Table 3: Extent and production of major fruit crops.
| Crop |
Extent (ha)
|
Production ('000fruits/bunches*)
|
Production (mt)
|
Banana
Mango
Lime
Orange
Pineapple
Papaw
Passion fruit |
46659
25825
6691
3704
4766
2953
441
|
34394*
489552
151469
27147
41063
32972
8994
|
412728
80776
4544
3393
51329
21432
764
|
Table 4- Extent and Production of Vegetables-1996
| Crop |
Extent(ha)
|
Production(mt)
|
Bean
Tomato
Capsicum
Cabbage
Radish
Carrot
Beetroot
Knol-khol
Leeks
Brinjal
Bandakka
Red pumpkin
Bitter gourd
Snake gourd
Cucumber
Ash pumpkin |
7109
6729
2812
3244
2244
2241
2170
1487
1425
1139
9518
7066
6374
3597
2615
2196
826
|
28939
42470
10381
40126
19830
24374
13301
12063
191484
15227
68164
37330
60990
20449
19412
18002
6442
|
The value of
fruits and vegetables produced is estimated at Rs. 20 billion which
is equal to the value of paddy produced in Sri Lanka. A total of 0.2
m hectares of horticultural crops produce almost the same rupee value
as the total rice crop cultivated in about 0.8 m hectares illustrate
the high income generating potential of these crops.
Potential for
employment generation in the horticulture sector is very high due
to the possibilities of value addition through processing, packaging,
product development and marketing. Therefore this sector provide many
opportunities to solve the current socio-economic problems in the
country.
A significant
increase has been observed in export earnings from horticultural crops
in recent times. The total foreign exchange earnings from fruit and
vegetable export for the year 1996 has exceeded Rs. 1 billion (Table
5). The total export value of fresh fruits and vegetables has increased
from Rs. 48 m in 1983 to Rs. 377 million in 1996. The corresponding
value for processed products has increased from Rs. 31 to Rs. 611
during the same period.
Table 5: Export of fruits and Vegetables (1995-1996)
| Product |
1995 |
1996 |
| Volume (mt) |
Value (Rs.m) |
Volume (mt) |
Value (Rs.m) |
Fresh vegetables
Fresh fruit
Processed fruit & vegetables |
6140
4423
10946
|
294
121
531
|
6910
4150
9525
|
272
105
677
|
| Total |
21509 |
946 |
20585 |
2054 |
Constraints
The constraints that deter the expansion of fruits and vegetable sector
in Sri Lanka can be categorised as follows:
1. Unavailability of suitable varieties to meet the requirement of
processing and export industry
2. In adequate availability of good quality seed and planting materials
3. Imbalanced fertilizer use
4. High incidence of pests and diseases and improper pesticide use
5. Higher degree of dependence on the rainfed system and inadequate
use of modern irrigation techniques.
6. Inefficient resource management practices adopted by farmers leading
to low productivity resulting high cost of production.
7. Seasonality of production and drastic price fluctuation
8. Higher percentage of post harvest losses due to inappropriate handling,
storage and transportation
9. Inadequate storage facilities and outdated methods adopted in processing
of fruits and vegetables.
10. Inadequate marketing facilities and poorly operated distribution
net work
11. Unavailability of land and support services for large scale commercial
production.
Research Perspective
Horticultural research and development institute :
Research on horticultural
crops has been mainly undertaken by the Horticulture Crop Research
and Development Institute (HORDI) of the Department of Agriculture
(DOA). Head quarters and main research facilities are located at Peradeniya
near Kandy - the hill capital. Regional research centers in different
agro ecological regions focus research on vegetable and fruit crops
grown in those regions. (Figure 4)
In collaboration
with the national agricultural system, international donors and other
NGOs the work of HORDI ultimately benefits mostly the small scale
producers.
HORDI is committed
to developing and promoting more sustainable horticulutre systems
and practices through varietal development, with yield and quality
objectives in mind and evolving methodology for optimal resource usage
avoiding natural resource degradation. Also constant monitoring of
produce marketing and educating the producer exporter and retailers
of bench mark standards required by the local and export industry,
so that a profitable fruit and vegetable cultivation is fostered in
the long run.
Services are concentrated
on areas of public interest with identifying and understanding client
and extension worker needs and involving people engaged in national
development and delivery of services to satisfy their needs. Following
two years of rapid expansion in staff and activities HORDI achieved
a solid purposeful programme of work envisaged to brighten up the
future of horticultue in several important areas. Presently over 75
scientists and of many technical staff are working on various aspects
of fruits and vegetables grown in Sri Lanka.
Research communication
and Technical leaflets published regularly added to clients knowledge.
Collaborative work of soils & water management centre of the department
support a sustainable cultivation while crop protection division constantly
monitors the pest and disease status of the crops. A healthy dialogue
is maintained always by the HORDI staff with the Food Technology Centre
on Post Harvest management practices.
Regional centres
work on specific problems related to the regions such as adoptability
testing of varieties and problems related to crop protection. These
centres also undertake cropping system research and socio-economic
studies before the final recommendation to farmers is made.
Research projects
are formulated by the staff in consultation with the extension staff,
large scale producers and other clients of HORDI. According to their
perceived economic benefits to farmers and hence crops that are widely
grown often receive more attention (eg. chillie, beans, brinjal, tomato,
banana, papaya and pineapple). Research is also undertaken to develop
crops with an export market (green chillie, bittergourd, rambutan
and avacado). Research at the regional level also function to solve
problems faced by farmers of that particular region. These problems
are presented by Extension Division of the provincial department of
agriculture biannually to the Regional Technical Workshop Group (RTWG)
comprised of Research, Extension, Education & Training Planting
Material and Seed divisions.
Achievements
Crop Improvement
Tropical Fruits
Fruit crop improvement programme is primarily based on the evaluation
of local germplasm and introductions. Several introduced varieties
were evaluated and based on yield, quality and adoptability evaluation
several varieties have been released (Table 6).
Table 6: Varieties of fruits developed by the Department of Agriculture
| Crop |
Variety |
| Avocado |
Simmonds, Fuerte, TowerII, Booth Pollock Purple hybrid |
| Papaya |
Ratna |
| Mango |
Malwana, Kartha colomban, Willard & Vellai Colomban,
Peterpassand |
| Rambutan |
Malwana No. 1 |
| Banana |
Nadee |
| Mandarin |
Madhu |
Mango : In line
with the attempts to develop horticulture for export market. Department
of Agriculture introduced and tested in 1970's over 30 exotic varieties
known to possess qualities demanded by the export market. But some
of these varieties did not flower under local conditions while those
that flower did not yield satisfactorily. The quality is not acceptable
to domestic market. Present day thinking is to promote the locally
adopted, locally acceptable varieties to satisfy the local market.
Recently a good quality high yielding variety named "Malwana" selected
from local germplasm has been released (Table 6).
Banana : There
are two principal types of banana grown in the country. Alukehel
of the ABB group is the cooking type while Kolikuttu and Suwandel
belong to AAB group and are esteemed high as desert type. However,
Embul (meaning sour) another variety in AAB group is the most
widely grown variety with a high potential in the local market. A
local improved selection of the 'Embul' type having high quality fruits
and high yield was developed recently and released (Table 6). Embon
is the only cavendish type of banana grown locally. However, fruits
get detached when ripe. Hence it is unsuited for export. Two cavendish
types were introduced and tested. Among them IC2 was found suitable
for cultivation in the wet zone. Guidelines for Banana propagules
production using tissue culture techniques and associated virus indexing
procedures have been perfected to produce virus free planting materials.
Pineapple: There
are two principle types of pineapple cultivated in Sri Lanka. The
'Mauritious' variety is the most popular desert variety cultivated
as an intercrop in the coconut plantation is the intermediate zone
of the country. The other variety in 'Kew'of the, smooth cayenne type
is cultivated to a lesser extent for processing.
Rambutan: A long
term experiment indicated that "Malwana number One" to be the best
of all introduced and local varieties tested. The fruits are larger
(weigh 40-50 g) and deep red in colour when ripe. Farmers are currently
changing over to this variety by top working of their existing trees
of the non descript type.
Citrus: A selection
of the mandarin variety "Clementine" named "Madhu" was released. A
hybrid between Lime and Lemon called "Lemmonine" was released. This
plant bears fruits throughout the year and juice is excellent as a
squash. It is expected to bridge the gap in production of lime during
the off season.
Papaya: A Pureline
selection of a Malaysian variety was released to the farmers recently.
This new variety is named "Ratna". It's 60% hermaphrodite. Fruits
weigh approximately 650g and are oblong in shape. Flesh colour is
deep red. Fruits stands transport as flesh is firm. Hence it is suitable
for export.
Passion fruit
: Using purple passion fruit (Passiflora edulis) as the female
plant a successful cross was made with the yellow passion fruit (P.
edulie, flavicarpa). A selection from the progeny of this cross
exhibited exceptionally good fruit quality flavour and yield. It was
named "Rahangala Purple" and recommended for upcountry areas.
Yellow passionfruit
variety is mainly cultivated in the low country wet zone of Sri Lanka.
The crop is grown as an intercrop under coconut or rubber. Viral diseases
together with colllor rot pose a constant threat to these plantations.
Regional Research Station at Bombuwela (wet zone) identified three
promising varieties. One is a selection from an exotic introduction
named Bombuwela selection and the other two were bred at Bombuwela.
They were named Bombuwela hybrid 1 and Bombuwela hybrid 2. To get
over the soil borne infestation the use of Yellow variety as a stock
plant was recommended.
Jak: Of the six
varieties tested the variety. "Father long" was found to be superior.
Individual fruit lets are larger (31.12g/fruit let without seed) juicier,
and has a pleasant aroma.
Durian: In Durian
(Durio zbetainus) where there is high genetic variability due
to cross pollination, superior mother plants can be identified and
their budwood is used for propagation of superior types. Mother plants
of 83 accessions were identified and could be divided into soft and
hard flesh types. There were other variations interms of colour of
rind, fruit shape, flesh colour and odour and fruits with aborted
seeds (flesh to seed ratio is high). Additionally, plants bearing
in the off season were identified.
Temperate Fruits:
Peach: Low-chill
deciduous fruit crop varieties bred by the University of Florida;
USA were introduced to hill country with success. Local peach was
used as the stock and compatibility was excellent. This fact made
things easier to disseminate quality germplasm. As almost every household
in this area (Welimada Plataeu) carries few local peach plants, a
programme was initiated to graft those plants with scion from improved
varieties. The varieties used were Tropic Beauty, Tropic snow, Tropic
sweet Flodaglo; Sunblaze and Gulf Ruby (Plum).
Strawberry : At
elevations 1600m of the hill country plants grow faster but yields
are poor. In this region of the upcountry farmers do cultivate strawberries
mainly for runner production, while at lower elevation and drier part
of the hill country strawberries are grown for processing. The principal
variety grown is "Kendall". However recently a project to grow strawberry
under cover for export, in the wetter more cooler region of the hill
country was started.
Vegetables
The vegetable
breeding programme is essentially an evaluation and selection programme,
and is closely integrated with other disciplines to identify high
- yielding varieties with desirable characteristics such as resistance
to important pests and diseases. Emphasis is also placed on selecting
varieties suitable to each agroecological zone.
Almost all the
low country vegetable (tropical type) varieties recommended to the
farmers are the results of a well planned vegetable breeding programme
of the DOA. (Table 7).
Table 7: Varieties of vegetables bred by the department of Agriculture
| Crop |
Variety |
Luffa
Cucumber
Bitter gourd
Snake gourd
Pumpkin
Tomato
Eggplant
Capsicum
Radish
Okra
Wingbean |
LA33
LY53
MC 43
TA-2
ANK
KWR, T-146, T245
Vihara Hybrid
SM-164, Padagoda
CA-8
Beeralu, Bola
Haritha, MI5
SL44, SLS 40, UPS 122 |
In exotic vegetables
from temperate countries such as carrots, cabbage and cauliflower,suitable
varieties are selected from varietal introductions. Seed importers
supply HORDI with samples of new varieties produced by their parent
companies abroad.
Hybridization
programme is restricted to crops like brinjal, tomato, capsicum and
okra.
In solanaceous
crops like capsicum, tomato and brinjal one of the major objective
of the breeding programme is resistance to bacterial wilt. Currently
mutation programmes is underway in tomatoes to select high quality
tomato varieties with bacterial wilt resistance. In brinjal, in addition
to bacterial wilt moderate resistance to shoot and pod borer is among
the breeding objectives.
Soil & Fertility Management
The main emphasis
has been to develop fertilizer recommendations for different vegetable
crops. Fertilizer recommendations for vegetables were first formulated
by the DOA in 1980. From then on Soil Scientists in DOA have been
conducting fertilizer response studies on different vegetables with
the view to improve these recommendations. In 1993 the DOA introduced
a programme to provide farmers with soil test based fertilizer recommendations.
This is gradually gaining popularity particularly among the vegetable
growers.
The suitability
of recommending locally available rock phosphate for vegetables in
place of the currently recommended triple superphosphate, which has
to be imported, has been examined. Such studies have shown that even
in strongly acidic soils, rock phosphates are unable to meet the P
requirements of vegetables. Even partially acidulated rock phosphate
has not proved to be promising P source for vegetables.
Response to K
fertilizer is seldom observed. However, K response studies are being
conducted on different soil types. Studies are also being conducted
on the use of animal manure as a source of K for vegetables.
In the upcountry
region there is intensive vegetable cultivation in rotation with potato,
throughout the year. Farmers in this region use more than recommended
quantities of fertilizer in addition to large amounts of cattle and
poultry manure. As a result these soils are loaded with excessive
amounts of P and K. Levels as high as 300 ppm P and K are not unusual
for these soils. Experiments conducted in the upcountry clearly show
the benefits of using manures together with chemical fertilizers.
An experiment conducted through nine cropping seasons in the upcountry
on an acidic soil (pH 5.1) has shown that considerable yield increases
can be obtained by applying 5 t/ha poultry manure alone or in combination
with recommended quantities of NPK fertilizer to vegetables. At HORDI
studies on the use of cattle and poultry manure as P sources for vegetables
have shown that the quantity of TSP recommended for vegetables can
be reduced when either cattle or poultry manure are also used. Analysis
of soils from plots treated continuously with manure show gradual
increase in P content. For instance in the poultry manure treated
plots Olsen P content of soil increased from an initial value of 3.5
ppm to 14.5 ppm after 6 cropping seasons, whereas in plots receiving
poultry manure+NPK the P content increased to 42.5 ppm. Thus showing
the importance of adjusting the quantity of fertilizer P added to
vegetables when manures are also used, in order to minimize P build
up which could lead to nutrient imbalance. Build up of P was least
in cattle manure treated plots.
By encouraging
farmers to adopt soil test based fertilizer recommendations it is
hoped that the build up of nutrients in the upcountry soils can be
retarded and the productivity of the soils improved.
Regular application
of lime with no reference to soil acidity is another practice among
vegetable growers. However, experiments conducted in the upcountry
through three seasons on a soil of pH 4.6 have failed to prove the
benefits of liming. Regular application of lime results in gradual
increase in soil pH, indicating that liming may not be necessary where
poultry manure is regularly used.
At present no
macronutrients are recommended for vegetables. However Scientists
having recognized the need for such recommendations are conducting
micronutrient response studies. Some work has also been done on micronutrient
uptake by the harvested portions of vegetable crops. There is a need
to pay more attention to these nutrients.
Crop protection
A large number
of insects, diseases and weeds are known to infest different vegetable
and fruit crops. The major insect pests and diseases of vegetable
and fruit crop are given in the Appendices 1,2,3 & 4.
Although there
are many control methods available, use of chemicals remain to be
the chief method of control of both insect pests and diseases in vegetables.
In fruit crops, pest and diseases are controlled only occasionally.
Various biological
control methods have been attempted in vegetable though only limited
success is achieved in most of the cases. A number of predators and
parasitoids of some of the important vegetable pests have now being
identified. However, their importance have been evaluated only for
a few species. Attempts were made to control diamond back moth through
introduced parasites such as Horgenus corophage and Thyraella
colloris. Subsequent studies have shown T.colloris have
been establish. Although releases of parasite of beanfly. (Ophiomia
phaseoli). Ophius importatis were made at few locations of vegetable
growing areas, subsequent studies have failed to recover them in the
field. Various strains of Bacillus thuringiensis (Bt) have
been tested against tomato fruit borer and cabbage caterpillars. Some
of these strains were found to be promising and recommended for field
use. However, use of Bt at the field level remains to be low due to
its high cost and narrow use range. Several entomophogenic fungi have
being locally isolated and methods were developed to culture them
in cheaply available media.
The field of biological
control of plant diseases in vegetables is generally much more recent.
Several antagonistic fungi have been identified against root and collar
rot causing pathogens. Some of these are being multiplied on inexpensive
media and tested in the green house.
Resistant varieties
serve as an important foundation for integrated pest management. Inspite
of this, progress of breeding such materials has been slow particularly
in the case of insect pests. Several varieties of brinjals and tomatoes
are found with resistance to bacterial wilt, P. solanacearum. Progress
of research to breed a papaya variety with papaya ring spot virus
resistance has been encouraging. Resistant papaya variety to this
virus will be released shortly.
Various mulches
such as plastic and paddy straw were tested for its effectiveness
on various pests infestation. Infestation by aphids was low in a capsicum
crop mulched with plastic compared to a non-mulch crop. Mulching with
paddy straw reduce cut worm damage in tomato.
A classic case
of crop rotation in controlling bacterial diseases is that of tomato.
Farmers in Matale district rotate tomato with paddy. The crop is planted
in Yala (dry season) followed by paddy in the Maha (wet
season) P. Solanacearum which causes bacterial wilt in tomato
is unable to live under anaerobic conditions. Hence six months rotation
is effective in controlling the disease.
Plamodiophore
brassicae which causes club root of cabbage is particularly active
in acidic soils therefore application of 5-10 tons/ha of lime is recommended
to control this disease. The lime is incorporated into the soil about
a month before transplanting the cabbage. Application of various plant
materials were also found to suppress the club root. Green manure
crops radish and mustard are recommended when soil borne diseases
are causing serious problems. These may have antifungal properties
due to their mustard oil content which can reduce the population of
soil borne pathogens.
Use of various
traps have been gaining popularity among farmers. Pseudo-stem traps
are useful in reducing the population of banana stem and root weevil.
Partial control of mango fruit fly was achieved through the use of
methyl eugenol traps.
Vegetable farmers
depend heavily on pesticides to keep their crops free of pests. This
inadvertently has resulted in many undesirable problems such as pesticide
resistance, adverse effect on natural enemies, excessive residue on
harvested crops, environmental contamination and serious health hazards.
Many of these problems are well recognized by the DOA. Consequently,
only pesticides that fall into WHO class II and Class III are normally
recommended to farmers. The use of monocrotophos and methamodophos
has now been banned and are gradually being replaced by safer pesticides.
More emphasis is placed on the recommendation of synthetic growth
regulators such as chlorfluzuron.
Recently there
is a growing interest towards botanical pesticides. Neem, Azardiracta
indica has been recommended for the control of Cabbage caterpillars.
Commercial preparation of neem is now available in the market.
Post harvest and processing technologies
The post harvest
losses of fruit and vegetables is estimated to be around 30-40% which
contribute to high market prices. Reduction of post harvest losses
reduce unit cost of production, lower the prices and increase the
farmer income.
The method of
handling, packing and storage that are being adopted have been developed
over the years by producers transport agents and dealers using their
innovative abilities and skills using some cheap and commonly available
materials.
Packaging of fresh
produce is very basic. Horticultural produce are often transported
in gunny bags and wooden crates and woven baskets. In floricultural
industry packaging is more organized and live plants and cut flowers
are exported in corrugated cartoons.
Fresh produce
is transported in gunny bags, wooden crates, in vans, trucks, bullock
cart etc. Due to poor ventilation and poor condition of the roads
there is a rapid deterioration of the produce.
The current emphasis
of the research is the development of low cost appropriate technology
to reduce post harvest losses and to increase value through preparation
of dried and processed forms of production of vegetables and fruits.
Post harvest life
of fruits and vegetables depend on the stage of harvesting. Harvesting
indices have being determined for mangoes, bananas, rambutan and vegetables
like tomato and okra.
Shelf life of
beans, tomatoes and banana can be increased by storing them in polypropylene
bags at 24-250C. Controlled atmosphere (5% 02
+ 5% C02) can also be used to extend the storage life of
Embul bananas for 30 days at 14oC.
Methods have been
developed for the preservation of fruits and vegetables by dehydration
and preservation of pineapple and papaya in fruit juices without adding
sugar and preservatives. These methods were demonstrated to fruit
processors engaged in export trades.
Marketing
The overall marketing
system for fruits and vegetables is not well developed in the country.
It is characterised by frequent gluts in production,consequent upon
price crashes and distress sales at throwaway prices during bumper
harvest in certain location on the one hand and irony of unsatisfied
consumer demand on the other.
The bulk of the
marketing is carried out by the commission agents and large traders
of the private sector. The clientele consists of the retailers in
the urban markets, vendors, restaurants hotels and institutions such
as the army and hospitals.
The chain of intermediaries
begin with the village level collecting agents and the most usual
marketing channel is the farmer-assembler-wholesaler-retailer-consumer
systems. However the flow follows different channels depending on
the distance of the market to the producing area involving more intermediaries.
Movement of produce
is mainly by open trucks from producing areas to the markets and packaging
is in gunnies and baskets resulting in heavy losses by driage and
damage causing heavy losses to the producer. It is estimated that
35-40% is lost from the point of production to the consumer table
owing to lack of knowledge on pre and post harvest handling. Traditionally
transport is charged on a piece basis and this tend to over load the
produce in gunnies/baskets causing damage by crushing and heating.
Export market
demands that produce be handled with much more care, harvesting at
correct maturity, treatment to arrest deterioration, pre-cooling to
reduce field heat and refrigerated transport etc. are pre-requisites
to export.
Lack of an efficient
and fast transmission system for market information does hamper the
marketing of produce in time, resulting in deterioration in quality
and quantity. Primary producers get information of the market mostly
through village level traders and fellow producers, who have traded
in the produce earlier in the season. As a result of this ignorance
some middlemen tend to exploit producers.
Since traditional
agricultural commodities faced slow growth in the world market attention
was directed towards more market oriented crops, obvious ones being
horticultural crops. This trend caused enormous technical and social
changes in horticultural growers. Global market studies were conducted.
Trade intelligence studies enabled producers and traders to plan more
effectively the overall production and guided them in expansion or
conversion to other crops. Many supporting agencies were in the field
providing technical, marketing , promotional and advisory assistance
to the investors.
The most significant
trend for the Horticultural Industry has been the steady and continued
growth of the exports in response to the higher quality product offered
to the export market. (Table 5).
REFERENCES
(1) Abeytunga S. and V.Arulandy 1990. Vegetable Research in Sri Lanka
In: Vegetable Research and Development in South East Asia p. 40-49
Proc. of a workshop held in Islambad Pakistan 24-29 Sept. 1990.
(2) Chandrasekera L.B.,(1984) Rubber Research Institute, Annual Reports
Vol 81,82,83.
(3) Gunawardhana S.D.I.E. 1993. Fruit Production, Research and Development
in Sri Lanka In: Research & Development of fruits in the Asia
Pacific region Edit. BB. Singh p 185-207.
(4) Jayawardena, S.B.G. and S.J.B.A.Jayasekera 1994, Status of Vegetable
Production in Sri Lanka and special reference to vegetable hybrid
technology. Paper presented at the Expert Consultation Meeting of
the Regional Network of Vegetable Crops, Bangkok, Thailand 1994.
(5) Kudagamage, C. 1990. Status and Management of major vegetable
pests in Sri Lanka. In: Status and Management of major vegetable pests
in the Asia-Pacific Region. Edit. Lim Guan- soon and Di Yuan-Bo. Expert
consultation on Integrated Pest Management in major vegetable crops
held from 14-16 Nov. 1988 Bangkok.
(6) Weerasinghe S.P.R and V. Arulandy 1980. Vegetable Production in
Sri Lanka In: Vegetable Research and Development in South East Asia
Edit. S. Shunmuganadan P30-39 Proc. of a workshop held in Islamabad
Pakistan 24-29. Sept. 1990.
Peiris J.W.L. A Histroy of fruit cultivation in Sri Lanka. A FAO/UNDP
project report on Horticulture and Research and Development 127 p.
Appendix 1
Major insect pests of selected vegetables
| Crop |
Major pests |
| Crucifers |
Plutella xylostella (Diamond backed moth)
Crocidolomia binotalis
Spdoptera litura
Hellula undalis (Cabbage web worm)
Chrysodeixis eriosoma (Cabbage loopers)
Brevicoryne brassicae (Cabbage aphid)
Agrotis ipsilon (Cut worm) |
| Cucurbits |
Dacus cucurbitae (Melonfly)
Leptoglossus spp (Leaf footed bug)
Epilachna spp (Epilachna beetle)
Empoasca spp (Leaf hopper)
Aphid gossypi (Cotton aphid)
Myzus persicae (Potato aphid)
Tetranychus spp (Red spidermite)
Bemisia tabaci (White fly)
Aulacophora spp
Lasioptera spp
Thrips palmi (thrips) |
| Egg plant |
Leucinodes orbonalis (shoot and pod borer)
Empoasca spp (Leaf hopper)
Tetranychus spp (Red spider mite) |
| Tomato |
Heliothis armigera (Pod borer)
Spodoptera spp (Pod borer)
Bemisia tabaci (White fly)
Thrips tabaci (Onion thrips) |
| Okra |
Empoasca spp (Leaf hopper)
Sylepta derogata (Leaf roller)
Earias febia (Pod borer)
Tetranychus spp (Red spider mite)
Disdurcus spp |
| Bean |
Ophiomyia phasoli (Beanfly)
Marula testulalis (Pod borer)
Heliothis armigera
Tetranychus spp. (Red spider mite)
Frankliniella spp (Thrips) |
| Leafy vegetables |
Halticus tibialis(sucking bug)
Spodoptera litura (Leaf eating caterpillars)
Heliothis armigera (do)
Plusia agramma (do)
Terias spp (do)
Lamprosema indicata (do)
Chetocnema spp (Leaf eating beetles)
Cassida spp (-do-)
Thrips |
| Capsicum |
Aphids
Myzus persicae (Potato aphid)
Aphis grossypii (cotton aphid)
Scirtothrips dorsalis (chillie thrips)
Thrips tabaci (Chillie thrips)
Hemitarsonemus latus (Mites)
Spodoptera litura (Pod borer)
Heliothis spps (Pod borer) |
Appendix 2:
Insect pests of selected fruit crops
| Crop |
Pests |
| Banana |
Cosmopholites sordidus (Rhizome weevil)
Odoiporus longicollis (Stem weevil)
Pentalomia nigronervosa (Banana aphid) |
| Avocado |
Zeuzera coffee (Stem boring caterpillar)
Xyleborus morigerus (Shot-hole borer)
Bactrocera dorsalis (Fruit fly) |
| Rambutan |
Icerya seychellam (Scale insects)
Pulvinaria psidii (Scale insects)
Planococus lilacinus< |
| Mango |
Sternochetus mangiferae (Seed weevil)
Bactrocera dorsalis (Fruit fly)
B.Kandyansis (Fruit fly)
Idioscopus clypealis (Mango hopper)
Idioscopus niveosparus (Mango leaf hopper)
Amritodus brevistylus (Mango leaf hopper)
Deporaus marginatus (Leaf-eating and cutting ~weevil)
|
| Citrus |
Papilio demoleus (Leaf-eating caterpillar)
Phyllonistis citrella (Leaf minor)
Taxoptera spp (Citrus aphid)
Planococos citri (Citrus mealy bug) |
| Pineapple |
Mealy bug (Dysmicoccus brevipos) |
Appendix 3:
Major diseases of selected vegetable crops
| Crop |
Disease |
Egg plant
Okra
Cucurbits
Beans
Capsicum
Tomato
Leafy vegetable
(Gotukola)
Leafy vegetable
Mukunuwanna |
Bacterial wilt (Pseudomonas solanacearum)
Blight (Phomopsis vexans)
Root and collor rot
(Colletotrichum spp & Phytophthora spp
Little leaf disease Mosaic (Okra Mosaic virus)
Powdery mildew (Erysiphe cichoracearum) Downey mildew
(Pseudoperonospora cubensis)
Powdery mildew (Erysiphe cichoracearun)
Anthracnose (Cerocospora citrullina)
Fusarium wilt (Fusarium spp)
Soft rot (Erwinia carotovora)
Angulor leaf spot (Pseudomonas lachrymans)
Bacterial wilt (P. solanacearum)
Cucumber mosaic virus Pythium rot (Pythium spp)
Collor rot (Sclerotium rolfsii)
Fusarium root rot (Fusarium solani)
Rust (Uromyces spp)
Bacterial blight (Xanthomonas phaseoli
Anthracnose (Colletotrichum lindemuthianum)
Bean mosaic virus Damping off (Pythium spp)
Rhizoctonia solani, Fusarium solani, Macrophomina phaseolina
Anthracnose (Colletotrichum capsici, C. gloesporioides)
Leaf spot (Cercospora capsici)
Collor rot (Sclerotium rolfsii)
Bacterial wilt (P. solanacearum)
Chilli mosaic viruses
Bacterial wilt (P. solanacearum)
Late blight (Phytophthora infestans) Anthracnose
(Colletrotrichum spp)
Leaf spot (Alternaria spp)
Damping off (Pythium spp)
Rhizoctonia solani, Fusarium solani, Macrophomina phaseolina
(Peronospora spp)
Cucumber mosaic virus
Potato virus -Y
Tomato mosaic virus
Tomato spotted wilt virus
Curly top virus Leaf blight
Causal agent fungus
Colletotrichum orbicularae
Leaf spot
(Cercospora spp
Wilt
Causal agent Bacteria
Pseudomonas solanacearum
Mosaic
(Cucumber mosaic virus)
Red spot
(Cercospora spp)
White rust
(Albugo spp)
Root and Stem rot
(Fusarium spp)
Alternaria rot (Black spot)
(Alternaria alternata) |
Appendix 4:
Major diseases of selected fruit crops
| Crop |
Disease |
Mango
Banana
Papaya |
Anthracnose Colletotrichum gloesporioides Gray
leaf spot Pestalotia mangiferae Powdery mildew
Oidium mangiferae Stem-end rot Botrydiplodia
theobromae Dothiorella dominicana
Anthracnose Colletrotrichum musae Panama
disease Fusarium oxysporum Sigatoka leaf disease
Mycosphaerella musicola Verticillium theobromae
Bacterial soft rot Erwinia spp Banana Bunchy
top virus Infectious chlorosis Cucumber mosaic
virus Banana streak Banana streak virus
Bract Mosaic (Banana Bract Mosaic virus) Anthracnose
(Colletotrichum gloeosporioides) |
| Crop |
Disease |
Papaya
Pineapple
Avocado
Jack fruit
|
Phytophthora fruit rot and root rot Phytophthora
palmivora Powdery Mildew (Oidium caricae)
Rhizopus soft rot ( Rhizopus stolonifer) Papaya
ringspot (Papaya ringspot virus) Bumpy fruit
(Boron deficiency)
Butt rot, black rot, and white leaf spot (Thielaviopsis
paradoxa) Root rot (Phytophthora spp)
Anthracnose Colletrotrichum gloeosporiodes Root
rot Phytophthora cinnamomi Stem end rot
(Dothiorella aromatica) (Botrydiploidia theobromae)
(Pestalotiopsis versicolor) Scab Sphaceloma
perseae Fruit rot Phytopthora spp Rhizopus
spp Root diseases (Fomes lignosus)
(Fomes noxius) (Rosellinia bunodes) (Sphoerostilbe
repens)
|
| Crop |
Disease |
Rambutan
Citrus
(Lime) & Sweet
Orange
|
Pink disease
Dorticium salmonicolor
Fruit rot
Causal agent - fungus
Diplodia spp
Anthracnose
Colletotrichum gloeosporioides
Fruit rot
Phompsis spp
Fruit rot
Rhizopus spp
(Diplodia spp)
Canker
Xanthomonas campestris
Anthracnose
Colletotrichum gloesosporioides
Gummosis
(Phytophthora spp)
Powdery mildew
(Oidium tingitaninum)
Scab disease
(Elsinoe fawcettii)
Pink disease
(Corticium salmonicolor)
Tristeza virus
(Citrus tristeza virus) |
|
| |
|
|
|
|
|
|
|
|
|
|
|
Green - Seeds Co., Ltd.
81/10B Ho Van Hue Street, Phu Nhuan District, Ward 9, Ho Chi Minh City, Vietnam
Tel: +84 (8) 847 6901 - Fax: +84 (8) 844 1392 - Email: info@green-seeds.com
|
|
|
