VANILLA

        Vanilla is specialty spice crops which is used as flavoring and coloring agents in culinary purposes. Vanilla is orchid kind of plants, belongs to Orchidaceae family. Plants are succulent,  climb the support with the help of areal roots. Commercial vanilla is a cured unripe fruits. Curing is a important process to impart aroma into fruits. Production of Vanillin, facilitated by enzymatic activities during curing brings aroma to vanilla. Vanilla is used for various desserts, craemes, jams, cookies are flvoring agents.

             Madagascar is the leading producer of  vanilla, in terms of quality and quantity. Indonesia ranks next, followed by Uganda, Papau New Guinea, mexico and China. In India,   Karnataka is the largest producer of vanilla, followed by Kerala and Tamilnadu. Crop is mainly grown as an intercrop, along with planation crops  like cofee, cocao, areca. Crops requires long waiting period of 4-5 years for first harvest and some more months of  curing period to make them merchantable. 

         There are a few cultivated species of vanilla, Mexican Vanilla (Vanilla panifolia), West Indian Vanilla (vanilla pompona), Thahitian vanilla (Vanilla thahitensis). Among them, mexican vanilla is largely grown and known for high quality Vanillin production.

Mulch the soil surface below the venilla plant to avoid weed growth, retain the soil nutrient, humas and health which receives heavy continuous rain. Regulate the shade in such a way that shun shine should be optimum reach the plant.  Plant requires continuous  rains of 6-9 months followed by sunny days of few months for flowering.    

Cultivation of Vanilla Plants:

      Climatic requirement: Vanilla is crop of humid tropic, requires long spell of precipitation and short summer. Area receiving annual rainfall of 1500-3000mm is best suited for cultivation. Humidity of the area should be constant ranging between 80-85 % as areal roots absorbs moisture from air. The crop is grown under regulated shade. Shade should be regulated in such way that scorching sun should not cause withering of succulent shoots on one hand and sun rays reach the entire plant which is essential for photosynthesis. Ideal temperature for better growth is 21°C to 32°C. Extremely low temperature halts the growth.

Soil requirement:  Crop prefers loose soil rather compact clay kind.  Loamy and lateritic soil with well trenched  drainage aids in proper establishment, growth and flowering of crops. 

Planting and Spacing: Vanilla is propagated through stem cuttings or  rooted cuttings or tissue cultured cuttings. Stem cuttings are prepared at  a lenth  of 2-4 ft with  and planted at pits dug at the  dimension of  30cm3 at a space of  2-2.5m x 1.2-1.5 m in plains.  At hilly area spacing of  1.5m x1.5m is maintained. Stem cuttings are faster way to get established plants and to have early harvest. In case of rooted cuttings, cuttings of  foot length with few nodes intact are prepared and planted in polybags containing rooting mixture.  Poly bags are kept in shades and watered regularly.  Cuttings with well developed roots are ready to transplant with in 6 months. Tissue culturally developed seedlings are also can be used. These seedlings are known for already  availibility, free from diseases and show uniform growth. 

       Planting and maintaining supports or especially live trees are very import in vanilla cultivation.  Medium sized plants like Gyricidia maculata,  Erythrina subumbran, Plumaria alba (Champa or West Indian Jasmine) are used. These trees are to pruned regularly to maintain the height to the reachable extent to facilitate easy pollination and harvesting of pods.   Optimum branches are maintained to regualate enough shade and sunshine.

       Trailing of vanilla plant:  Trailing is very important to keep the length of the plant at optimum level. This facilitates easy pollination and harvesting.  Plants are made to climb the support upward and later made to grow horizontally. 

Pests of vanilla

            Vanilla is a humid tropic crops which attract quite a few number of pathogens and pests which are detrimental to their growth and yeild. Important insect pests are white grubs, vanilla weevils (Sipalus sps.), Vanilla bugs (Halyomorpha sps.), Leaf eating beetles (Saula ferrunginea), Caterpillar (Plusia aurifera), sucking pests like aphids, thrips, mealy bugs.

Non insect pests like snails and slugs (Achatina sps), earwigs also affects the crops.

Halyomorpha sps.: It is otherwise called stink bugs which emits foul smell when disturbed. It feeds on buds, inflorescence, some time fruits to cause damage to plant. Collect the bugs and their egg mass and destroy.

Vanilla weevil: These are elongated snouted weevils, which has the habit of boring into stem, along with supporting trees. Mechanial collection and destroying them is usefull.

Leaf eating beetles: Saula ferrunginea, are tiny, rusty beetles usually predates sap sucking insects like thrips, scales and mites, they feed on leaf by under surface leaving only upper epidermis layer of leaves. Some times they feed on flower and buds.

Leaf eating caterpillars: Slightly greenish caterpillars of moth Plusia aurifera feed on leaves. Collect and destroy.

Snails: These are polyphagus pest which feed on leaves, tender shoots and pods of vanilla. Can capable of multiplying fast by laying hundreds of eggs. Hand picking and destroying, application of sevin dust as mollusicides. Collect them by placing wet sacks or empty containers by placing upside down. Keeping the any decomposing material away from plants.

Root grubs: Here grubs feed on roots of plant to make them wilt and die. Under severe condition drenching of soil with 0.05% of Cholrpyripos is useful.

Pollination in Vanilla:

              Vanilla crop  mainly depends on Orchid bees (Euglossa sps.) for pollination. Hand pollination is labor intensive.   This is because of less number or absence of Orchid bees meant for their pollinations. Alongside, flowers blooming period is very short, usually starts as early as 4.00 am   and fades away by noon. Floral structure itself does not allow them get them pollinated naturally. Presence of a tissue flaps called rostellum in between anther and stigma acts as barrier for pollens reaching ovary. Lifting this barrier carefully by hand and fuse the anther and stigma is called hand pollination. Here small tooth picks are used to insert and unfurl  petals and to expose middle tube like gynoecium to locate rostellum. The rostellum is carefully lifted by using tooth picks and anther at the top is pressed gently against sticky stigma at the bottom by using thumb and fingers. Successful pollination results in formation of pods with in few weeks. The process is labor intensive and needs certain degree of expertise and patience to make it successful.

Diseases of Vanilla

Vanilla gets infected with few important pathogens mainly fungal counter parts. Fusarium wilts, phytopthera rots, Antracnose, Rusts are important fungal diseases.  Cymbidium Virus, Watermelon mosaic virus are important viral diseases. 

Fusarium wilt: The disease is caused by soil borne pathogen fusarium oxysporum. On infection pathogen develops lesions on stem and roots, causing rotting of affected parts in advanced conditions. At higher degree of infestation that causes wilting entire plants. Predominant during wet season where soil moisture is high and atmosphere is humid. To control the same avoid soils and planting materials from infected area. Destroy the affected plants along with weed plants around it. Remove and dispose soils around the affected plants. 

Phytopthera rots: Otherwise Known as black rot, as it causes appearance of grayish to black lesions on stem, leaves and pods. prominent during rainy season. Heavy rains associated with poor drainage encourages the disease incidence. To manage the disease ensure proper drainage around the plants. Avoid excess mulching and shading  to the plants.  Collect and destroy affected plant parts to avoid further spread.

Anthracnose : Small, sunken dark spots produced on leaves, pods and stems. Caused by Colletotrichum sps. Condition favoring phytophthora rots also  favor this disease. Regulation of shade and mulching, ensuring proper drainage are helpful to manage the disease.

Rust: Caused by Euromyces sps. Causes yellow to orange pustules on under side of leaves. In advance condition leaves shows yellowing, necrosis and drying.  Excess shade, crowded planting, excess rain and water logging condition favors the disease incidences.   Collecting and destroying affected plants, ensuring proper drainage comes handy in management of  the disease.

Cymbidium mosaic virus and Odontoglosum ring spot virus : Causes yellow patches and curling or distortion of leaves. It is common virus for most of the orchid plants. 

Vanilla necrosis virus/ watermelon mosaic virus: causes severe veinal necrosis and dieback. Irregular pale yellow patches are found on younger leaves where as older leaves develop pale yellow scab. The virus is vectored by aphids. The disease is managed by controlling vectors and maintaining  proper sanitation in the field. 

Harvesting and Curing of Vanilla:

     Vanilla starts bearing flowers at third years of planting. Reducing the watering and sometimes nipping of tip may initiate flowers if vine continue to grow vegetative. Pods are ready to harvest 9-10 months from pollination. Attain of pods dark green color and tip start showing yellowing is the sign of maturity. Delay in harvesting may lead to splitting of pods. 

 Vanilla pods do not have any aroma when harvested.  Curing imparts Vanillin in vanilla, a crystalline substance responsible for its aroma and flavor. Curing is a tedious and labor intensive process. Firstly freshly harvested beans are dipped in hot water of 55-60°C for few minutes to put halt on natural growth of the pods. Later wrap the warm pods in cloth blankets and keep in airtight container for 10-15 days. There pods attain dark brown to chocolate color. Then remove the pods from containers and unwrap and keep it for gradual drying. Pods are dried alternatively in morning sun light and later in shade. Continue the process for 3-4 weeks till the pods attains optimum moisture level of 25-30%. Too much drying makes the pods brittle with lowered Vanillin content,   where as lesser drying induce mold formations. As a last step, store the dried beans in closed boxes or jars store in dark and cool place for several months for conditioning or aging.  Even curing also huge time and labors, completion requires 5-6 months.