Central Horticultural Experiment Station(CHES), Chettalli

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Dr P.C. Tripathi
Principal Scientist & Head
This station situated in Kodagu district of Karnataka was transferred to IIHR from the Govt. of Karnataka with effect from February 1, 1972.   Occupying an area of 92 ha., the mandate crop of the station has been Coorg ma ndarin with major emphasis on citrus die-back.  The station also works on fruit crops like sapota, guava, papaya, pineapple, passion fruit, minor fruits like pummelo, avocado, mangosteen,  and of late has diversified into floricultural crops.  The station has a strong nursery unit for production and supply of disease free citrus planting material, other plant materials and  Trichoderma cultures.  All the research work along with research laboratories of the erstwhile Citrus Experiment Station, Gonikoppal were shifted to CHES, Chettalli with effect from 1.1.1992

CHES, Chettalli -At a Glance


Central Horticultural Experiment Station, Chettalli (District- Kodagu, Karnataka) is a regional station of Indian Institute of Horticultural Research (IIHR), Bangalore under Indian Council of Agricultural Research (ICAR), New Delhi. The Centre was started as Orange Research Centre in 1947 by erstwhile while State Government of Coorg. The Centre was transferred to IIHR in on 1st February 1972.


To undertake basic and strategic research for enhancing productivity, quality and utility of horticultural crops of the Coorg region.

To act as a repository of plant genetic resources and scientific information in relation to horticultural crops.

To undertake front line demonstration in new technologies evolved and to impart training for upgrading scientific knowledge of technical personnel involved in horticultural enterprises.

Location and Infrastructure

The station is located near Chettalli 20 km from Madikeri on Chettalli –Suntikopa road in the Kodagu District of Karnataka. It is accessible by road from Suntikoppa (10 km) or Madikeri (20 km). The nearest railway station is Mysore (135 km). The centre is situated at 1050 m above mean seas level. The mean temperature of the station range between 320C and 190C.The annual rainfall is 150 cm with major precipitation during July and August. The soil is deep, dark brown, well drained sandy loam to sandy clay loam.

            The station has 94 ha of farm area to conduct various field experiments which divided into 5 blocks for efficient management. Five research laboratories, a library and an administrative wing are located in the main building within the experimental farm. A scientists' rest house, departmental canteen and residential quarters are also available on the campus. The sanctioned strength of the staff at the centre includes 6 scientific, 19 technical and 5 administrative and 35 supporting staff.

Germplasm collection and varietal development : Total 575 accessions of Citrus representing mandarins, sweet oranges, sour oranges, pummelos, grapefruit, limes and lemons and two related gene Poncirus trifoliata (trifoliate Orange) and Fortunella sp. (Kumquates) were collected. The germplasm was evaluated for its adaptability and suitability to the region. It was also screened against important pests and diseases (aphid, psylla, mite, scales, powdery mildew and Phytophthora root rot). Promising accessions (138) have been selected and are being maintained in a compact block. Detailed descriptions of these accessions have been made for floral and vegetative characters, fruit quality parameters etc. Extensive research works have been conducted to standardize the rootstocks for Coorg mandarin. Eighty one species /varieties/strains/cultivars were evaluated for rootstock purpose for Coorg mandarin. Rangpur lime (Citrus limonia Osbeck), Cleopatra mandarin (Citrus reshmi Tan), trifoliate orange (L) Osbeck) were found most suitable. The Rangpur lime was found vigourous rootstock and adaptable to wide range of soils and moderately tolerant to Phytophthora and most of the viruses except exocortis. Cleopatra mandarin is moderate in vigour, suitable for sandy loam soil, fairly resistant to viruses and tolerant to drought, salt and cold. Trifoliate orange was found dwarfing, hardy, good fro heavy soils, resistant to Phytophthora root rot tolerant to cold and drought, high productivity, excellent fruit quality and resistant to nematodes. Troyer citrange was found a vigourous rootstock, tolerant to Phytophthora root rot, Citrus Tristeza virus and citrus greening and suitable to all types of soils.

The collection of clones of Coorg mandarin has been made from the grower's orchards. These collections have been maintained and are under evaluation at the station and some of them are promising. In one promising clone,  plants are vigorous and upright, having dense canopy with or without thorns. Fruits are subglobose, depressed at distal end, frilled at stock end; ripe fruits are deep orange, orange yellow or yellow in colour. Average fruit weight is 90 to 105 g with 10-12 segments. Fruits contained 40% juice with, TSS 100 Brix and 0.4-0.6% acidity and 41.6mg/l00 ml ascorbic acid. The average yield of a ten year old plant is 800-1000 fruits. Fruits have excellent shelf life.

Production technology for Coorg mandarin

The improved production technology for Coorg mandarin has five different components. The use of standardized rootstocks for Coorg mandarin such as Rangpur lime, trifoliate orange, rough lemon should be done. These rootstocks have been standardized for Coorg mandarin based on their adaptability to various kinds of soil, resistance /tolerance to various diseases and higher quality fruits. The coffee based cropping system with two row of coffee at 2.8m x 2.8m and  one row of Coorg mandarin at 2.8m x 5.5m was found most profitable. The application of 600g N, 200g P2O5 and 400 g K2O per tree per year for the healthy budded plants of Coorg mandarin is recommended for Optimum growth and productivity. One of the major problems in the Coorg mandarin-growing area is the deficiency of micronutrients especially zinc. Three to four sprays of Zinc sulphate (0.2%) and magnesium sulphate (0.5%) with lime during new flush period is recommended for better growth and production. For control of citrus mealy bug, lady bird beetle (Cryptolaemus montrouzieri Muls) should be used. Bt and Verticilium lecani can be successfully used for control of Citrus butterfly and soft green scale, respectively. Trichoderma harzianum should be used for control ofPhytophthora diseases.

Technology for rejuvenation of Coorg mandarin

The rejuvenation technology for Coorg mandarin consist application of nutrient through soil and foliar application and control of diseases and pests. The soil application of 25 kg FYM + 5kg Neem cake + 150g Trichoderma harzianum + 400g N, 125g P205 and 275g K20 in two splits (pre- and post-monsoon) + l kg dolomite twice (June and October)is recommended. The remaining 220g N, 75g P2O5 and 25 g K2O should be given as 8-10 foliar applications at monthly intervals. Application of Zinc sulphate (0.2%), magnesium sulphate (0.5%) calcium chloride/ calcium nitrate(0.5%)  once a month is recommended. Spraying of imidacloprid / monocrotophos at 10 days interval during peak flush periods and at  15 days intervals  during other periods is recommended for control of disease transmitting vectors. Spraying of Wettable Sulphur (0.3% ) at monthly intervals during post monsoon periods, soil drenching with metalaxyl or mancozeb + metalaxyl (0.2 %)  or potassium phosphonate (0.3 %) and foliar application of 0.2 per cent metalaxyl / phosetyl AL / potassium phosphonate four times a year is recommended for disease control.


In Coorg region, mandarin is grown as intercrop in coffee plantations. Coorg mandarin in coffee based cropping system with two row of coffee at 2.8m x 2.8m and  one row of Coorg mandarin at 2.8m x 5.5m has been found most profitable .In pure mandarin orchards, inter cultivation with papaya and pineapple were found profitable during the pre-bearing period.

Water management

Water requirement of Coorg mandarin is different in growth and reproductive phases. In order to avoid moisture stress during growth phase, irrigation at 10 days interval from March to end of April is beneficial in sustaining the vigour of plants. However, in the reproductive phase, irrigation should be given as blossom shower either through sprinkler or drip irrigations (18-20 litres of water per day per plant for one week-one acre inch) during March-April and thereafter supportive irrigations to ensure sufficient soil moisture for retention and good growth of fruits. Mulching the basins with dry leaves during summer conserves soil moisture. To minimize the damages arising from the development of soil-borne diseases, effective drainage is necessary.

Pest management


Fixed plot and roving surveys were carried out for years in different Coorg mandarin orchards of the region. The results revealed that leaf minor, oriental red mite, black citrus aphid, psylla, orange shoot borer were the major pests occurring in varying intensity round the year. The control measures for these pests were recommended. Leaf minor and Citurs psylla can be control by spaying of imidacloprid ( 0.3 ml/l) or quinalphos (2ml/l) or fenvalerate (0.5 ml/l) at the time of new growth. Citrus aphids and scales can be effectively controlled by spraying of  dimethoate (1.7ml/l) or quinalphos(2.ml/l). Fruit fly can be managed effectively controlled by Setting up methyl eugenol pheromone traps( 4 /acre) for control fruit fly and while bait traps for fruit sucking moth during fruiting seasons have been found effective. In case of organic cultivation, prune the affected and dried shoots and spray with Neem soap (1 %) or Pongamia soap (1%).Biological control studies of Citrus pests revealed that ladybird beetle (Cryptolaemus montrouzieri Muls.)(10 grubs/tree) can be used successfully for the management of Citrus mealy bug infestations while  Verticillium lecani ( 1%) controls the incidence of soft green scale effectively.

Disease management

The Coorg mandarin plants have been affected by a number of fungal, viral and bacterial diseases. The higher infection of these diseases and the other abiotic stresses has created such a situation that it becomes difficult to grow healthy crop in the region with out proper management of these biotic and abiotic stresses. The station has extensively worked on the management of these factors .Among the fungal diseases are Phytophthora root rot, foot rot, stump rot, gummosis leaf and fruit rot, powdery mildew, are important. The research works on epidemiology, management of these diseases through evolving resistant rootstocks, improved cultural practice such higher budding height and chemical and biological control were carried out. A package of practices was recommended for integrated management of Phytophtora infections in Coorg mandarin which includes (a) application of 100-150g of Trichoderma harzianum Culture along with 5kg neem cake per plant and Akanum (b) Use of Coorg mandarin budded plants raised on Rangpur lime or Cleopatra mandarin root stocks. (c) Avoiding low budding, proper planting in the field maintaining tree trunks free from sprouts (d) application of Wettable Sulphur (0.3% ) at monthly intervals during post monsoon periods, soil drenching with metalaxyl or mancozeb + metalaxyl (0.2 %) or potassium phosphonate (0.3%) and foliar application of 0.2 per cent metalaxyl / phosetyl AL / potassium phosphonate four times a year is recommended for disease control.

The disease like powdery mildew can control by the application of Wettable sulphur (0.3%) or Carbendazim (0.1%) or Contaf(0.2%) on new flushes.

Among the virus and virus like diseases associated with the Citrus decline are greening, Tristeza and psorosis .The citrus black aphid and psylla are the vector responsible for spread of these diseases. The indexing of the trees of the orchards of the region suggests the major role of greening disease in the decline of Coorg mandarin. On the basis of the findings of the trails,some management approaches were suggested for the control of these diseases


A gynodioecious variety of papaya "Coorg Honey Dew" has been selected from the honey Dew variety and released for commercial cultivation in 1959. The variety has become popular throughout the country. The variety produces no male plants. The fruits are long to oval, weighting 2.0 to 3.5 kg and of excellent quality. Each plant bears 40-60 fruits and an average yield of 200 tons per hectare could be obtained over a three year cropping period. A spacing of 2.5 x 2.5 m and an application of 250g N and 250 P2O5 and 500g K2O per plant per year in six split doses is recommended for optimum growth and productivity of the variety.

Passion Fruit

  'Kaveri' a hybrid between purple and yellow varieties of passion fruit has been developed at the station and released in 1986. The hybrid produces ovoid to round, purple dotted fruits with 20-25 per cent juice content. The juice is sweet with 11.5- 12.0 per cent total sugar and 3.0 ­3.5 % citric acid. The variety is high yielding (16-20 kg per vine per year) and is tolerant to Alternaria leaf spot,Fusarium collar rot and nematodes. A fertilizer dose of 90g N, 60g P2O5 and 90g­ K2O per vine per year in three split doses is recommended for optimum growth and productivity.


Production technology for cultivation of the crop under Coorg conditions has been developed. A plant population of 45,000 per hectare with a spacing of 25 x 60 x 105 cm is most suitable for obtaining high yield of 60-70 tonnes per hectare in Kew variety. Nitrogen @ 12 and 16 g per plant per year is recommended under rainfed and irrigated conditions respectively. Phosphorus at 4g as basal dose and 12g of potassium in three split dose per plant per year are optimum. Uniform induction of flowering under humid climate of Coorg can be obtained by application of 10 ppm napthalene acetic acid (NAA) during December­- January, while 25 ppm ethrel in combination with 2 per cent urea and 0.04 percent sodium carbonate was effective during rest of the year. Optimum stage for induction of flowering was 35-40 leaf stage with '0' leaf weighing 39-40 g. Pre­plant application of Bromacil 2 kg and Diuron 2 kg per hectare is recommended to check weeds for 6-9 months during monsoon. Application of phorate granules (0.75 kg a.i./ha) at 100 day intervals controls mealy bugs which cause severe wilt of the plants.


Sapota var. Cricket ball has been excellent adaptability to the region and has become one of the remunerative crops in recent years. A fertilizer dose of 500g N, 250g P2O5 and 250g K2O per tree per year in two split applications recorded the highest yield and good quality fruits in 25 year old plants under rainfed conditions of Coorg. A promising extra large sapota selection with mean fruit weight of 238g and mean fruit volume of 250cc has been identified at the station. It is a heavy yielder with a mean yield of 260 kg per tree. The selection is found to possess tolerance toPhaeopleospora leaf spot, a disease which causes extensive defoliation in the humid tropical climate of the region.


Guava var. Allahabad Safeda is performing quite satisfactorily giving high yield and good quality fruits. Preliminary observations have indicated that higher population densities of 555 and 416 plants per hectare gave significantly higher yield, relative yield and resulted in maximum yield efficiency and land use index.

Under utilized fruits

The different under utilized fruits were collected from diverse sources and maintained in the field gene bank at Central Horticultural Experiment Station, Chettalli. More than 200 collections of under utilized fruits comprising of mangosteen( 16 accessions ), Durian (11 accessions), Rambutan (50 accessions), avocado ( 12 varieties), Passion fruit (12 accessions ) ,   Kokum- Garcinia indica L. ( 10   accessions ), Malabar tamarind – Garcinia gummigutta L. ( 3 accessions ), Macadamia nut ( 3 accessions) and longan ( 2 accessions ) are being maintained and evaluated for various characterstics. Some of them are promising. Two promising lines of Rambutan are also identified .Rambutan CHES-27 is free stone, bold, pulp easily separates, fruits are red, ovoid to round in shape, number of fruits per tree: 859, average fruit weight is 42.54g with 17.6 O Brix TSS and low acidity (0.4-0.5%) and high pulp content (40%).The other line,   CHES – 14 is also a free stone variety but fruits are yellow and round with average Fruit Weight: of 23.20g and 17.1O Brix TSS.


Seed and plant multiplication

 The station has 4 hectare nursery unit good infrastructure for multiplication of diseases free healthy plants for Coorg mandarins. The mother plants as well the seedlings and buddlings are maintained under net house for protection against vector transmitted diseasesHealthy and disease-free plants of other citrus species and the passion fruit variety 'Kaveri' are being raised In addition, budded plants of about 250 rose varieties and pepper and cinnamon plants are also being propagated for distribution. About 50,000 plants are being distributed annually to growers. Breeder Seed of Coorg Honey Dew Papaya are being multiplied to supply to the growers all over India.



 An apiary was established with the objective of studying the role of bee management practices for increasing productivity of horticultural crops and for increased honey production. All the four species of bees Apis dorsata, A. cerana indica, A. florea and Trygona sp. are found in the area. More than 50 plant species served as pollen and nectar forage for the bees during the year. Schefflera spp. and Bidens pilosa, are very good nectar sources during April to June. The maximum honey flow periods are during April-May and December. Dividing colonies during March with four frame strength was the best in colony building and honey production. An ant proof stand has been developed and popularized. There was sustainable yield increased was observed in most of fruit crops and coffee. 50% of crop yielding was observed in citrus by bee pollination. The station is providing training and technical guidance to the growers of the region on honey bee management.

Trichoderma and mushroom spawn production

Trichoderma harzianum- kodagu isolate was isolated from the soil of Kodagu region by the scientists of CHES, Chettalli. It has been found effective in management of pepper wilt, root rot of Coorg mandarin, rhizome rot of ginger and cardamom. Two applications ofTrichoderma one  as pre monsoon and other post monsoon were recommended for management of these diseases. One kg of Trichoderma mixed with 100 kg of FYM needs to be applied for disease control At Chettalli it is multiplied on coffee cherry husk and provided to the grower at reasonable costs.The spawn of oyster mushroom is being multiplied at the station. Sorghum is used at a base material for this purpose. The training of mushroom production is also organized for the growers.

A small demonstration production unit is functional at the station. The station is also maintaining a small demonstration unit of vermicomposting.

Services Available to the Farming Community

    Production and supply of healthy and disease free Coorg Mandarin plants
    Production and supply of Trichoderma, a bio control agent.
    Production and supply of fruits and ornamental plants.
    Production and supply of Oyster mushroom spawns.
    Nutrient diagnosis and advisory services for Coorg mandarin.
    Consultancy in horticulture

a.       Preparation of project reports

b.      Layout of orchards and guidance on establishment and after care

c.       Mushroom cultivation

d.      Scientific bee management and bee keeping.

e.       Recycling of agri- horticultural wastes through vermin-composting

f.        Field visits and guidance

Further information


Indian Institute of Horticultural research

Hessaraghatta Lake Post

Bangalore-560 0089

Phone-080-28466471 Fax-080 -28466291

Email: director@iihr.ernet.in



Central Horticultural experiment Station

Chettalli-571 248

Phone-08276-266635 Fax- 08276-266635

Email: cheschettalli@yahoo.co.in