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 oportant 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
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 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|
Root and Tubers
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 cund 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.
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.
Table 4- Extent and Production of Vegetables-1996
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
process 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
Table 5: Export of fruits and Vegetables (1995-1996)
ConstraintsThe 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 iri 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.
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)table 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.
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.
Tropical FruitsFruit 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
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 thinwhile 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 oth 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 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 de 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.
VegetablesThe 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 (tropic
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
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 selemme 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 ManagementThe 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.
mal 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 mtilizer 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 protectionA 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 availabl
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 mlant 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 whichse.
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 place 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 technologiesThe 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 approhasis 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.
MarketingThe 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 thders 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 villat 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).
(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: ReProduction, 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.
Major insect pests of selected vegetables
Insect pests of selected fruit crops