Black pepper (Piper nigrum L.) (Family : Piperaceae) is a perennial vine grown for its berries extensively used as spice and in medicine. India is one of the major producer, consumer and exporter of black pepper in the world. Black pepper is cultivated to a large extent in Kerala, Karnataka and Tamil Nadu and to a limited extent in Maharashtra, North eastern states and Andaman & Nicobar Islands. Kerala and Karnataka account for a major portion of production of black pepper in the country.Climate and soil
Black pepper is a plant of humid tropics requiring high rainfall and humidity. The hot and humid climate of sub mountainous tracts of Western Ghats is ideal for its cultivation. It grows successfully between 20° North and South latitude, and from sea level up to 1500 m above sea level. The crop tolerates temperatures between 10° and 40°C. The ideal temperature is 23 -32°C with an average of 28°C.
Optimum soil temperature for root growth is 26-28°C. A well distributed annual rainfall of 125-200 cm is considered ideal for black pepper. Black pepper can be grown in a wide range of soils with a pH of 5.5 to 6.5, though in its natural habitat it thrives well in red laterite soils.
The black pepper growing tracts in the West Coast of India include
- coastal areas where black pepper is grown in homesteads
- midlands and where black pepper is extensively cultivated on a plantation scale and
- hills at an elevation of 800-1500 m above sea level, where the crop is mostly grown on shade trees in coffee, cardamom and tea plantations.
A majority of the cultivated types are monoecious (male and female flowers found in the same spike) though variation in sex expression ranging from complete male and complete female is found. Over 75 cultivars of black pepper are being cultivated in India. Karimunda is the most popular cultivar in Kerala. The other important cultivars are Kottanadan (South Kerala), Narayakodi (Central Kerala), Aimpiriyan (Wynad), Neelamundi (Idukki), Kuthiravally (Kozhikode and Idukki), Balancotta, Kalluvally (North Kerala), Malligesara and Uddagare (Karnataka). Kuthiravally and Balancotta exhibit alternate bearing habit. In terms of quality, Kottanadan has the highest oleoresin (17.8%) content followed by Aimpiriyan (15.7%).
Seventeen improved varieties of black pepper have been released for cultivation. Panniyur-1, Panniyur-3 and Panniyur-8 are hybrids evolved at the Pepper Research Station, Panniyur (Kerala Agricultural University). IISR Girimunda and IISR Malabar Excel are the two hybrids released from Indian Institute of Spices Research, Kozhikode, Kerala.Propagation
Black pepper vines produce three types of shoot, namely
- Primary climbing shoot with long internodes having adventitious roots at nodes which cling to the supports/ standards;
- Runner shoots which originate from the base of the vine and creep on the ground, have long internodes which strike roots at each node and
- Fruit bearing lateral shoots.
Cuttings are raised mainly from runner shoots, though terminal shoots can also be used. Cuttings from lateral branches develop a bushy habit. Rooted lateral branches are used for raising bush pepper. Though seeds (berries) are fully viable, they are not generally used for raising plantations as seedlings will not be genetically uniform.
1. Production of rooted cuttings
a. Traditional method
Runner shoots from high yielding and healthy vines are kept coiled on wooden pegs fixed at the base of the vine to prevent the shoots from coming in contact with soil and striking roots. The runner shoots are separated from the vine during February - March, and after trimming the leaves, cuttings of 2 - 3 nodes are planted either in nursery beds or in polythene bags filled with potting mixture (soil, sand and farm yard manure in 2:1:1 ratio). Adequate shade has to be provided and the polythene bags are to be irrigated frequently. The cuttings become ready for planting during May - June.
b. Rapid multiplication method
A propagation technique developed at Sri Lanka has been modified for adoption in India for quick and easy multiplication of black pepper vines. In this method, a trench of 45 cm depth, 30 cm width and of convenient length is made. The trench is filled with rooting medium comprising of forest soil, sand and farm yard manure in 1:1:1 ratio. Split halves of bamboo or split halves of PVC pipes are fixed at 45° angle by keeping split portion facing upward on a strong support on one side of the trench. Rooted cuttings are planted in the trench at the rate of one cutting for each bamboo split. The lower portions of the bamboo splits are filled with rooting medium (preferably weathered coir dust - farm yard manure mixture in 1:1 ratio) and the growing vine is tied to the bamboo split in such a way to keep the nodes pressed to the rooting medium. Each single nodded cutting with the bunch of roots intact is cut and planted in polythene bags filled with fumigated potting mixture. Trichoderma @ 1g and VAM @ 100 cc/kg of soil can be added to the potting mixture. The buds start developing in about three weeks and then the poly bags can then be removed and kept in shade till main field planting. The advantages of this method of propagation are
- rapid multiplication rate (1:40)
- well developed root system
- higher field establishment and
- vigorous growth as a result of better root system.
c. Trench method
A simple, cheap and efficient technique for propagating black pepper from single nodes of runner shoots taken from field grown vines has been developed. A pit of 2.0 m × 1.0 m × 0.5 m size is dug under a cool and shaded area. Single nodes of 8 - 10 cm length and with their leaf intact are, taken from runner shoots of field grown vines. They are planted in polythene bags (25 cm × 15 cm, 200 gauge) filled with a mixture of sand, soil, coir dust and cow dung in equal proportions with their leaf axil exposed above the potting mixture. After keeping the bags in the pit, the pit should be covered with a polythene sheet. The cuttings should be irrigated at least five times a day with a rose can. Cuttings in poly bag are drenched 2 - 3 times with copper oxychloride (2 g/litre).
After about 1 month, new shoots start emerging from the leaf axil. The cuttings can be taken out of the pit after two months of planting and kept in a shaded place and watered twice a day. These cuttings will be ready for field planting after about 2 ½ months. By this method 80 - 85% success rate can be obtained.
d. Serpentine method
Serpentine layering technique can be used for product ion of rooted cuttings of black pepper in a cheap and effective manner. In a nursery shed with roofing sheet or shade net, rooted black pepper cuttings are planted in polythene bags holding about 500 g potting mixture, which will serve as mother plants. As the plant grows and produces few nodes small polythene bags (20 ×10 cm) filled with potting mixture may be kept under each node. The node may be kept gently pressed in to the mixture assuring contact with the potting mixture with the help of a flexible twig such as mid rib of a coconut leaflet. Roots start growing from the nodes and the cuttings keep on growing further. The process of keeping potting mixture filled polythene bags at every node junction to induce rooting at each node is repeated. In three months the first 10 to 12 nodes (from the mother plants) would have rooted profusely and will be ready for harvest. Each node with the polythene bag is cut just below the rooted node. The cut end is then also buried into the mixture to induce more roots. Polythene bags used are filled with solarized potting mixture fortified with bio - control agent. The Potting mixture is prepared by mixing two parts of fertile topsoil, one part of river sand/granite powder and one part of FYM (2:1:1). The rooted nodes will produce new sprouts in a week time and will be ready for field planting in 2 - 3 months time. The growing vines are to be irrigated every day with a rose can or sprinklers. By this method, on an average, 60 cuttings can be harvested per mother plant in a year.
e. Soil - less nursery mixture
Partially composted coir pith and vermicompost (75:25) enriched with Trichoderma (in talc formulation, 10 7 cfu/g at the rate of 10 g/kg ) is an ideal potting medium for black pepper nursery for healthy planting material production using plug - trays compared to conventional multiplication.
The plug - tray nursery technique involves initial multiplication of black pepper runners in a modified serpentine method, ie. by allowing runners to strike roots in the partially decomposed coir pith and vermicompost (75:25) bed of convenient dimension (1.5 m width, 10 cm height and convenient length). The vines trail on rooting medium and strike roots at every node. After 45 - 60 days, leaving the terminal 5 nodes, about 15 - 20 node rooted runner is cut into single node rooted cuttings and transferred to plug - trays (cell dimension of 7.5 × 7.5 × 10.0 cm) filled with soil - less nursery mixture [composted coir pith and vermicompost (75:25) enriched with Trichoderma ]. Better rooting and establishment is recorded under humidity controlled green house (27±2 ° C) with intermittent mist. The cuttings are retained in the trays for about 45 - 60 days (4 - 5 leaf stage) for initial establishment. The established cuttings are then transferred to shade net/ naturally ventillated green house for hardening (45- 60 days). Healthy black pepper rooted cuttings are ready for field planting after 120 - 150 days.
2. Nursery diseases
a. Phytophthora infection
Phytophthora infection is noticed on leaves, stems and roots of cuttings in the nursery. Dark spots with fimbriate margins appear on the leaves, which spread rapidly resulting in defoliation. The infection on the stem is seen as black lesions which result in blight. The symptoms on the roots appear as rotting of the entire root system.
Spraying Bordeaux mixture (1%) on leaves and drenching soil with copper oxychloride (0.2%) at monthly intervals prevents the disease. Alternatively, metalaxyl - mancozeb (0.125%) or potassium phosphonate (0.3%) could also be used. The potting mixture may be sterilized through solarization. To the sterilized mixture, bio agents such as VAM @ 100 cc/kg of mixture and Trichoderma harzianum @ 1 g/kg of soil ( Trichoderma population @ 10 10 cfu/g) may be added at the time of filling of nursery mixture in polythene bags. Since the biocontrol agents mainly protect the root system, the aerial portion may be protected with chemicals. If Bordeaux mixture is used care must be taken to prevent dripping of fungicide to the soil. Alternatively, systemic fungicides such as metalaxyl - mancozeb (0.125%) and potassium phosphonate (0.3%) which are compatible with Trichoderma may be used.
The disease is caused by the fungus Colletotrichum gloeosporioides . The fungus infests the leaves causing yellowish brown to dark brown irregular leaf spots with a chlorotic halo. Pre - planting treatment of two/three node cuttings by immersing in a solution of carbendazim + mancozeb (0.1%) for 30 minutes and spraying Bordeaux mixture (1%) alternating with carbendazim (0.1%) is effective against the disease.
c. Leaf rot and blight
The disease is caused by the fungus Rhizoctonia solani and is often serious in nurseries during April - May when warm humid conditions prevail. The fungus infects both leaves and stems. Grey sunken spots and mycelia threads appear on the leaves and the infected leaves are attached to one another with the mycelia threads. On stems, the infection occurs as dark brown lesions which spread upwards and downwards. The new flushes subtending the points of infection gradually droop and dry up. A prophylactic spray with Bordeaux prevents both the diseases.
d. Basal wilt
The disease is mainly noticed in nurseries during June - September and is caused by the fungus Sclerotium rolfsii . Grey lesions appear on stems and leaves. On the leaves white mycelium are seen at the advancing edges of the lesions. The mycelia threads later girdle the stem resulting in drooping of leaves beyond the point of infection and in advanced stages the rooted cuttings dry up. Small whitish to cream coloured grain like sclerotia bodies appear on the mature lesions. The disease can be controlled from the beginning stages, by adopting phytosanitary measures. The affected cuttings along with defoliated leaves should be removed and destroyed. After periodic sanitation, the cuttings are to be sprayed with carbendazim (0.2%) or Bordeaux mixture (1%).
e. Viral infections
Vein clearing, mosaic, yellow specks, mottling and small sized leaves are the most apparent symptoms for identifying viral infections in the nursery. As viruses are systemic in nature, primary spread occurs through planting material since black pepper is vegetatively propagated. When infected plants are used as source of planting material, the cuttings will also be infected. Hence selection of virus free healthy mother plants is very important for producing disease free cuttings. Secondary spread of the disease occurs through insects such as aphids and mealy bugs. When the poly bag cuttings are placed close and crowded in the nursery, chances of spread through these insects are more. Hence regular monitoring of the nursery for insects and spraying with insecticide like dimethoate (0.05%) should be resorted to whenever insect attack is noticed. Besides, inspection and removal of inf ected plants should also be done at regular intervals.
f. Nematode infestation
Root - knot nematodes ( Meloidogyne spp .) and burrowing nematode, Radopholus similis are the two important nematode species infesting rooted cuttings in the nursery. The damage caused to roots by nematode infestations result in poor growth, foliar yellowing and sometimes interveinal chlorosis of leaves. The establishment of nematode infected cuttings will be poor when planted in the field and such cuttings develop slow decline symptoms at a later date. Soil solarization or Steam sterilization can be done for sterilizing the nursery mixture. The sterilized nursery mixture may be fortified with biocontrol agents such as Pochonia chlamydosporia or Trichoderma harzianum @ 1 - 2 g/kg of soil, the product containing 10 6 cfu fungus/g of substrate. A prophylactic application of nematicide is also necessary to check the nematode infestation. For this, make three equidistant holes of 2 - 3 cm depth in the bag around the cuttings and place phorate* 10 G @1 g/bag or Carbofuran* 3 G @3 g/bag in these holes and cover with soil. Also, carbosulfan 0.1% @ 50 ml/bag can be applied to control nematodes. A light irrigation may also be given to ensure adequate soil moisture after nematicide application. In rapid multiplication nurseries where the rooted cuttings are retained for a longer duration nematicides may be applied at 45 days intervals as described above. (*banned in Kerala) .Establishment of plantations
Selection of site
When black pepper is grown in slopes, the slopes facing south should be avoided and the lower half of northern and north eastern slopes are preferred for planting. This will prevent vines from to the scorching effect of sun rays from southern direction during summer.
Preparation of land and planting standards
With the receipt of the first rain in May - June, primary stem cuttings of shade trees Eythrina sp or Garuga pinnata or Grevillea robusta (silver oak) or seedlings of Alianthus malabarica (Matti) are planted in pits of 50 cm × 50 cm × 50 cm size filled with cow dung and top soil. The planting is done at a spacing of 3 m × 3 m which would accommodate about 1110 standards per hectare. The black pepper vines can be trailed on the standards after three years when they attain sufficient height. Whenever E. indica is used as standards, application of phorate 10 G* @ 30 g may be done twice a year (May/June and September/October) to control nematodes and stem and root borer. When E. indica and G. pinnata are used, the primary stems are cut in March/April and stacked in shade till the stacked stems start sprouting in May. The stems are planted in the edge of the pits dug for planting black pepper vines. (*banned in Kerala) .
Pits of 50 cubic centimeters at a distance of 30 cm away from the base, on the northern side of supporting tree are taken with the onset of monsoon. The pits are filled with a mixture of top soil, farmyard manure @ 5 kg/pit and 150 g rock phosphate. Neem cake @ 1 kg, Trichoderma harzianum @ 50 g also may also be mixed with the mixture at the time of planting. With the onset of monsoon, 2 - 3 rooted cuttings of black pepper are planted individually in the pits on the northern side of each standard. At least one node of the cutting should be buried in to the soil for better anchorage.
As the plants grow, shoots are tied to the standard as often as required. The young vines should be protected from hot sun during summer by providing artificial shade. Regulation of shade by lopping the branch es of standards is necessary not only for providing optimum light to the vines but also for enabling the standards to grow straight. Adequate mulch with green leaf or organic matter should be applied towards the end of north east monsoon. The base of the vines should not be disturbed so as to avoid root damage.
During the second year, the same cultural practices are repeated. However, lopping of standards should be done carefully from the fourth year onwards, not only to regulate height of the standards, but also to shade the black pepper vines optimally. Lopping may be done twice (during June and September) in a year. Excessive shading during flowering and fruiting encourages pest infestations. From the fourth year, two diggings are usually given, one during May - June, and the other towards the end of south - west monsoon in October - November. Growing cover crops like Calapogonium mucunoides and Mimosa invisa are also recommended under West Coast conditions as an effective soil cover to prevent soil erosion during rainy season. During summer the cover crops dry up leaving thick organic mulch.
Manuring and fertilizer application
Manuring and fertilizer application for pepper vines is to be done for proper establishment and growth of plants. Application of lime or dolomite @ 500 g/vine in April - May during alternate years is recommended under highly acid soil conditions. Organic manures in the form of cattle manure or compost can be given @ 10 kg/vine during May. Neem cake @ 1 kg/vine can also be applied.
Recommended blanket nutrient dosage for black pepper vines (3 years and above) are as follows.
NPK 50: 50: 150 g/vine/year (General recommendation)
NPK 50: 50: 200 g/vine/year (for Panniyur and Kannur district in Kerala)
NPK 140: 55: 270 g/vine/year (for Kozhikode district in Kerala)
Soil test based fertilizer recommendations for dry yield target levels of 3 and 6 tons/ha