Morphology
Among the various floristic compositions orchids form one of the major groups found in all the vegetational types from western coastal region to mountains. The majority of orchids are found in the forests and each forest type has its own composition of orchid flora. High rainfall and the relatively cool climate coupled with bright sunshine contribute ideal habitat for the growth of epiphytic orchids. The profuse growth of moss on trees is well suited to the growth of small epiphytic orchids. Altogether 267 species, 3 subspecies and 2 varieties in 72 genera are reported from Western Ghats. Among them 130 species, 2 subspecies and 2 varieties are endemics to India. Of these, 72 species, 2 subspecies and 2 varieties are endemic to Western Ghats. Nineteen taxa are extremely rare and endangered.
Selection Criteria for Planting Materials
Terminal cuttings with one or two healthy aerial roots are ideal as planting material. Basal cuttings of 30 cm length with a few roots and leaves are also good.But they take longer time to sprout and grow. Sympodial orchids are propagated by separation of pseudobulbs. A plant with minimum two or three pseudobulbs with the basal root is ideal for planting.Some of the sympodial varieties produce sprouts at the top of pseudobulb called as keikis. Keikis when fully grown can be separated and planted.
Varieties
The popular genera of orchids that are suitable for growing in Kerala are Arachnis, Aranthera, Vanda, Phalaenopsis (monopodials); Aranda, Mokara (inter-generic monopodials); Dendrobium, Cattleya, Oncidium (sympodials).
Dendrobium is the most popular genus of Kerala. Some of the important varieties belonging to this genus are given below, grouped according to colour.
Purple and white : Sonia 17, Sonia 28, Sonia Bom Jo, Earsakul.
Purple : Renappa, New Wanee, Sabine Red, Jurie Red.
White : Emma White, Fairy White, Kasem White, Snow White.
Pink : Sakura Pink, New Pink.
Yellow : Sherifa Fatimah, Kasem Gold, Tongchai Gold.
Plantation
Broken bricks, gravel, tile bits, charcoal, coconut husk bits, tree fern etc. are some of the components of the media used for growing epiphytic orchids. The components are washed thoroughly before filling in pots. For terrestrial orchids, a mixture of humus, leaf mould, dried manure, chopped fern fibre and spaghnum moss will suffice.
Water Management
Always water early in the day so that your orchids dry out by nighttime. The proper frequency of watering will depend on the climatic conditions where you live. In general, water once a week during the winter and twice a week when the weather turns warm and dry. The size of your orchid container also helps determine how often you need to water, regardless of climate conditions. Typically, a 6-inch pot needs water every 7 days and a 4-inch pot needs water every 5 to 6 days.
Nutrient Management
Orchids require both major and minor nutrients. A low concentration of this is applied frequently as whole plant spray. Two sprays per week is generally enough. Micronutrients help in improving the quality and need to be applied once a month. The chemical fertilizers are to be properly balanced with organic manures like cowdung, cow urine, ground-nut oil cake Neem oil cake etc. They should be diluted before application.
Weed Management
Manual weeding is effective but expensive. Use of weedicides like paraquat is also practised. Mulching also reduces weed population.
Pest Management
The common pests attacking orchids are thrips, aphids, spider mite, soft scale, mealy bugs, orchid weevil, ants etc. Insecticides at suitable concentration can control all the insects. Other very serious pests of orchids are snails and slugs. They feed on the tender young shoots, roots and buds. Hand-picking is effective, if the number of plants is less. They move out during late night and hide before early morning. Damage is caused during this period. All the pests can be controlled by application of contact and systemic insecticides at appropriate concentration.
| Sl No: | Orchid Host | Disease Caused | Fungus Identified |
|---|---|---|---|
| 1 | Cattleya sp | Black rot | Pythium |
| 2 | Cattleya sp | Black rot | Pythium and Colletotrichum |
| 3 | Bulbophyllum sp | Leaf spot | Colletotrichum |
| 4 | Phiaus maculatus | Leaf rust | Uredo |
| 5 | Cymbidium Sp | Flower spot | Botrytis |
| 6 | lone scariosa | Black leaf spot | Colletotrichum |
| 7 | Zeuxine sp | Stem anthracnose | Colletotrichum |
Plant Protection
Some of the serious diseases are bacterial blight, leaf spot, anthracnose, root rot and damping off. Yellowing of the plants is the main symptom of blight. The disease is favored by warm and wet weather. To control the disease, cut and remove the diseased portion and spray streptocycline 200 mg/l. Anthracnose is a fungal disease in which the flowers rot. Mancozeb 0.2% spray can control the disease. This can control leaf spot disease also. Root rot is another major problem in anthurium. Improper aeration leads to this disease. Pests like scales, mealy bugs, thrips and mites are also common. Appropriate plant protection measures should be taken against them.
Harvesting
The spikes are harvested when a few buds at the top remain un-open. The spikes are cut with a small stalk. The cut end is dipped in a fungicide solution and then covered with a wet cotton swab and properly tied using a rubber band. They are then packed in carton of appropriate sizes and having proper ventilation holes. The spikes are inserted in polythene covers and packed loosely in the cartons.
Processing
One of the most important steps in postharvest treatment of cut flowers is to recut the flower stems at an angle under warm 38 to 44 C (100-110 F) water and place them in a plastic container filled with 100-150 mm (4-6 in) of floral preservative solution of the same temperature. At least 25 mm (1 in) of stem should be removed as well as foliage that would be below the water line in the container. Foliage in water will decay, causing damage to the flowers. Typical solutions contain 1% sugar, a biocide (200 ppm 8-HQC, 8-HQS, or Physan-20; or 50 ppm silver nitrate) and an acidifier (200-600 ppm citric acid or aluminum sulfate; 10-20 ppm when silver nitrate is used). The sugar replaces the flowers’ stored foods consumed by respiration, while biocides limit bacteria which plug up flower stems. Acidifiers aid in the uptake of water by reducing the pH to 3.5-4.5.
AverageYield & Area Under Cultivation
Local demands for flowers and plants for gardens are high, while opportunities for exporting orchids are even more promising.No appropriate measure of yield can be noticed.