Dr. Mohammad Shameem Al Mamun

Tea is an important cash crop as well as exportable commodity in Bangladesh. Tea produced in Bangladesh is exported in the tune of 1.5 million kg of made tea per annum meeting the internal domestic demand. Tea cultivation in Bangladesh was first introduced in the early part of 19^th Century. The first tea garden of Bangladesh was opened in Chittagong in 1840. Later in 1857 a commercial tea garden was established at Malnicherra in Sylhet. Bangladesh tea is grown in the two divergent ecological zones-namely, i) Surma valley in greater Sylhet and ii) Halda valley in Chittagong zone. Recently tea area is opened in Korotoa valley in Panchagarh districts (North-West of Bangladesh). Now, there are 167 tea estates having about 63 thousand hectare of tea plantation producing about 96 million kg of finished tea per annum.

 

Plant Habitat: Tea plant is an evergreen and perennial crop. The botanical name is Camellia sinensis. Tea plant grows to a height of 10 m. in natural condition if pruning is not performed. A tea bush can give economic yield commercially up to 50-60 years in favourable conditions. Generally broad leaf Assam type and small leaf China type tea variety are cultivated in Bangladesh.

 

Favourable Condition: Tea plant prefers mild forest condition. Warm and humid condition having 26-28ºC temperature, more than 2000 mm annual rainfall and 70-90% relative humidity are suitable for tea cultivation. Besides, day length should be about 12 hours; soil should be acidic (pH 4.5-5.8), sandy loam and sufficient nutrient content. The tea plants can not tolerate water logging condition. Neither extreme nor trace rainfall regime is not favourable for tea.

 

Propagation and Nursery Management:  Tea is propagated either by seeds or vegetative parts (clones). Tea seeds are collected from seedbaries. Tea seeds are sown at 20 cm x 20 cm by triangular method. Prior to planting, soil of seed or cutting nursery should be kept free form nematodes. Shade is essential for seedbaries. Shade frame may be constructed by bamboo splits at a height of 60-70 cm in each bed. Fertilizers (Urea, TSP & MOP) may be applied at 2:1:2 ratio for the growth and development of seedlings. Saplings are produced by vegetative propagation using improved planting materials i.e. clones. Cutting is produced using nodal stem having a complete leaf and a dormant bud from the mother bush of desired clones. Cuttings are planted in primary beds and after sprouting 2-3 leaves in 3-4 months cuttings are to be transferred to the nursery bag in the secondary bed. Shade frame may be constructed in the cutting nursery by using bamboo splits at a height of 150-180 cm. Water should be given in the nursery regularly. Always nursery should be kept free from weeds. Pesticides should be applied for the control of pests and diseases of tea seedlings when it is required.

 

Recommended Seeds and Clones: Five types of biclonal & polyclonal seed stocks viz. BTS1, BTS2, BTS3, BTS4 & NPS1 released from Bangladesh Tea Research Institute (BTRI) are disseminated to the tea industry for the good quality and yield than ordinary seeds. To increase the yield and quality of tea, BTRI has released so far 21 clones by clonal selection and breeding parallel to develop the seed variety. BT1, BT2, BT3, BT5, BT7, BT9, BT11, BT3 & BT14 are the standard clones. BT10 & BT12 are under high yielding clones. BT4, BT6 & BT15 are good cup quality clones. BT18 is drought resistant clone & BT21 is red spider mite resistant clone. 

 

Cultivation Method:

Land preparation and Planting Planning: 55 to 60 per cents of cultivable land of Bangladesh tea are under Tillah land. Tea cultivation is done by contour method in Hilly areas. Land is to be prepared by ploughing and subsequent laddering and weeding in high flat land.

 

Planting: Seedling should be planted during pre-monsoon season i.e. April/May. Planting can be done during December/March if ensuring the irrigation facilities.

 

Planting Spacing: About 18,518 plants/hectare are required for tillah plantation using spacing 90 cm x 60 cm in single row method; while 15,576 plants/hectare for flat plantation using 105 cm x 60 cm. 19,960 plants/hectare are required using 105 cm x 60 cm x 60 cm in double row method.

 

Planting Methods: Healthy and vigorous plant should be planted. For clonal tea, the pit size is 25-30 cm wide and 30-35 cm deep, while for seedling tea, 25-30 cm wide and 40-45 cm deep. The top soil is cut 23 cm deep and kept separately and mixed with fertilizer @ 2 kg cattle manure/compost, along with 30 g TSP and 15 g MP per planting pit. This fertilizer mixed soil should be kept inside the pit.

 

Mulching: Mulching should be done immediately after planting at 7-10 cm from the collar region at a height of 8-10 cm for the conservation of soil moisture during dry season. Water hyacinth, Guatemala or Citronella grass, even jungle scrub can be used as mulch materials.

 

Pruning: After planting up to 5 years old tea plant is recognized as young tea or immature tea. The objective of pruning of young tea is to encourage proper development of frame. High density of plucking points is achieved by pruning of young tea. If tea plant is planted during April/May, the pruning should be done in the last week of January or 1^st week of February of next year. Different methods are followed for pruning of young tea such as i) decentering ii) Pegging and iii) Ring-peg method etc.

 

Table 1. Pruning schedule of young tea

Year	Pruning operation	Pruning Height	Plucking Height
01	Decentering/Breaking	15-23 cm	50 cm
02	Prune	40 cm	50 cm
03	Skiff	50-53 cm	52-55 cm
04	Prune	45-50 cm	70-75 cm
05	Skiff	75 cm	78-80 cm

 

Mature tea pruning: The objectives of mature tea pruning are to maintain convenient height for plucking and to induce more vegetative growth. Depending on the situation pruning cycle may be three year cycle or four year cycle.

Three year cycle = Light Pruning        Light Skiff         Deep skiff

Four year cycle = Light Pruning        Deep skiff         Medium Skiff       Light Skiff         

 

Now-a-days three year pruning cycle is not practiced except prolong drought area only. In four year pruning cycle initial light pruning operation is generally given at 55 cm (22 inch) in 6^th year of planting and subsequent tipping is to be done at 20 cm above from the pruning mark. Deep skiff should be done at 65 cm and tipping at 75 cm in 7^th year. In 8^th year, medium skiff at 70 cm and tipping at 75 cm and light skiff at 75 cm and tipping at 77.5 cm in 9^th year. Thus, a four year cycle is completed and second four year cycle is started.

 

Table 1. Pruning schedule of mature tea

Pruning type	Pruning time
Light pruning	1st week of December to last week of December
Deep skiff	1st week of January to last week of January
Medium skiff	Middle of January to 1st week of February
Light skiff	Last week of January to whole month of February
Medium pruning	Once in 24-30 year from starting the cycle

 

Shade tree planting & take care: Tea plant can not tolerate extreme sunlight. So, shade is necessary requirement in weather condition of Bangladesh. It is necessary to go 50-70% of sunlight to the tea plants by this shading process. For this reason, shade tree should be established parallel to the planting of tea. Generally, Bogamedoloa, Crotalaria and Indigofera as temporary shade and Albizzia chinensis, Albizzia odoratissima and Derris robusta as permanent shade are planted in tea estates.  Temporary shade trees are planted at 3 m x 3 m spacing, while permanent shade trees are planted at 6 m x 6 m spacing. Making of pit of 90 cm deep x 60 cm wide, 10 kg rotten cowdung, 500 g TSP, 25 kg Ash and 500 g Dolomite should be applied per pit.

 

Plucking: Young shoots, leaf and buds are come out from the tea bushes during last week of March or 1^st week of April after pruning. This young shoots are tipping at convenient height. Thus, establishing a plucking table, then plucking is done at weekly interval.

 

Fertilizer Application: NPK fertilizers should be applied per plant with the growth and development of the seedlings.  Considering two starting and end points from 1000 kg to 3000 kg yield per hectare in a plantation, the fertilizer requirements are given below:

 

Table 3. Fertilizer schedule per hectare

Nitrogen     1st split	50 kg to 158 kg (Urea 110 kg to 300 kg)
2nd split	60 kg (Urea 130 kg)
Phosphorus 1 split	20 kg to 40 kg (TSP 44 kg to 88 kg)
Potash        1st split	30 kg to 75 kg (MP 60 kg to 150 kg)
2nd split	30 kg (MP 60 kg)

             

Besides, in order to fill up nitrogen deficiency and to increase growth of foliage, 2 kg Urea mixed in 100 litre of water should be sprayed to the foliage. In addition to 1% Potash with Urea should be sprayed to fill up potash deficiency. To fill up the zinc deficiency 200-400g ZnSO₄ in 100 litre of water should be sprayed. To reduce the acidity of soil 400-500 kg available dolomite per hectare should be broadcasted during the Light Pruning year.

 

Irrigation and Drainage: Water is an important element for the growth and development of plant. During dry season irrigation is given by sprinkler method to fill up the water stress in tea estates. In rainy season, water logging condition especially in low flat land occurs due to extreme rainfall. For this reason, proper drainage should be maintained by digging drain in a suitable way.

 

Pests of Tea: Tea production is greatly hindered due to insects, mites and nematodes. In Bangladesh tea, so far 25 insects, 4 mites and 10 species of nematodes have been identified. Tea mosquito bug, Termites & Red spider mites are the major pests of tea in mature tea plantation, while Aphids, Jassids, Thrips, Flushworms and Nematodes are the major pests of tea in nursery and young tea plantation. About 15% crop loss occurred by this pests per annum. In severe cases, it would be 100%. The short description and their control measures of major tea pests are furnished below:

 

1) Tea Mosquito Bug: Tea mosquito bug is the most serious pest of tea in Bangladesh. It is also known to Tea Helopeltis. Both nymphs and adults damage the plant by sucking sap from young leaves, buds and tender stems. The affected portions turn black. In severe attacks, the growth of new flush is completely checked. To suppress this pest, Malathion 57EC @ 2.25 lit in 500 lit of water per hectare should be sprayed at 7 days interval during dry period. In monsoon period, Viraat 23EC @ 0.7 lit or Ripcord 10EC/Decis 2.5EC @ 500 ml or Calypso 240SC @ 375 ml or ShengLi 30SC @ 250 ml in 500 lit of water per hectare should be sprayed at 7 days interval.

 

2) Red Spider Mites: Red spider mites are very harmful to tea. Minute in size. They attack both the upper and under surface of mature leaves.  Due to sucking out the contents, the whole leaf changes to a prominent bronze colour, dries up and drop. In severe attacks, young leaves are also infested. To suppress their infestation, any Sulphur based compound @ 2.25 kg/ha in 1000 lit of water can be used as prophylactic measure during early part of the season with 5-6 days interval. For palliative measure, Magister 10EC @ 600ml/ha or Mite Scavenger 10EC @ 500ml/ha or Oberon 240SC @ 400 ml/ha or Omite 57EC @ 1.00 lit/ha or Danitol 10EC @ 1.00 lit/ha in 1000 lit of water can be used with 6-7 days interval.

 

3) Termites: Termites are social insects as like honey bees. It is known to “Ulopoka” in tea estates. It is one of the major pests of tea. They feed on dead bark, rotten and live wood of tea plants. They live on colonies making mounds in the soil or stumps of plants. Only worker castes feed on tea plants. To protect standing tea plants from termite it is suggested to apply Admire 200SL @ 1.5lit/ha or Dursban 20EC @10lit/ha in 1000lit of water to the sub soil level up to depth 6 inches and upper level of plant up to infested area. 

 

4) Jassids: It is a major pest of nursery and young tea. Young shoots are also infested by this insect after pruning in mature plantation. They suck sap from the young leaves. Affected leaves become boat shape and leaf margins dry up. Dimethion 40EC @ 2.25 lit/ha or Ripcord 10 EC @ 500 ml in 500 lit of water should be sprayed at 7 days interval for the control of Jassids. Target point must be the lower surface of young shoots and leaves.

 

5) Aphids: This is commonly called plant lice. In Bangladesh tea, it is one of the serious pests of nursery and young tea. Aphids are more pronounced in tea recovering after pruning in mature plantation. Both nymphs and adults suck cell sap from the young shoots and leaves of tea collectively. So, the growth of plant is retarded. The presence of black ant confirmed the aphid infestation. Infestations are prominent during December to March. Ripcord 10 EC @ 500 ml in 500 lit of water should be sprayed at 7 days interval.     

 

6) Thrips: The adult thrips is tiny and slender brown bodied insect. It is one of the serious pests of nursery and young tea. Infestation is more pronounced in nursery and skiff areas. They also attack young new shoots of tea recovering after pruning in mature plantation. On the undersurface of mature leaves, two longitudinal sand papery lines form along the mid rib. Quinalphos 25EC @ 1.0 lit/ha or Intrepid 10SC @ 1.00 lit/ha in 500 lit of water should be sprayed twice at 7 days interval.

 

7) Flushworm: Immature stage of moths. It seems to caterpillar. Young flush i.e. two leaves and a bud tied together and curled telescopic in shape. The larvae of the pest roll up the top leaves and eat away. This malady is severe in the nursery, young tea and the field recovering after pruning. Hand collection is the best way for controlling this pest.

 

8) Field Cricket: Cricket is one of the most destructive pests of tea in nurseries and young teas. Strong mandibles present in their mouthparts. The front legs are remarkably developed for cutting roots and stem. They are nocturnal in habit and lives in burrows. At night it comes out to seek food. Pour one or two spoonful of waste engine oil per hole and subsequently pour water into the hole until the cricket appears and then destroy it by hand.       

 

9) Leaf Roller: Immature stage of moths too. Leaves rolled from to downward and feed inside. They feed within the leaf roll and the leaves become perforated. They generally attack the 2^nd to 4^th leaf. Hand collection is the best method of controlling the pest.    

 

10) Nematodes: They live in soil. Most of them are microscopic and not visible to naked eye. Filiform or thread like body. They suck sap of the young roots. Develop knots or galls. Plants show nutrient deficiency and stunted growth. Application of Furadan 5G @ 165 g/m³ soil is useful for the control of the pest.

 

Diseases of tea and their management: In Bangladesh tea, so far 22 species of pathogenic diseases have been identified. Major diseases of tea and their control measures are described below:

 

1. Black Rot: The disease appears on the mature leaves in tea plantation and leaves turn into yellowish dark brown. Macuprox 16 W @ 2.24 kg/ha in 1120 lit of water should be sprayed in foliar leaves of the bushes.

 

2. Blister Blight: Only young tea leaves and stems are infected and blisters appear as white velvety patches of irregular shape. Champion 77 WP @ 2.24 kg/ha or Calixin 80 EC @ 1.12 lit/ha in 1120 lit of water should be sprayed in foliar leaves of the bushes.

 

3. Die Back: The diseases begins to die at the end of the branches-hence the name ‘die back’. Champion 77 WP @ 2.24 kg/ha or Cupravit 50 WP @ 2.8 kg/ha or Calixin 80 EC @ 1.12 lit/ha in 1120 lit of water should be sprayed in foliar leaves of the bushes.

4. Red Rust: The blight of tea is an algal disease that affects the mature stem of the bush. Although the disease infects the stem but the symptoms appears on the leaves. Leaves become mottled with yellowish colour. Macuprox 16 W @ 2.24 kg/ha in 1120 lit of water should be sprayed in the affected stems of the bushes.      

 

5. Branch Canker: The infection of the disease is pronounced in the main stump or branches of tea bushes. The bark portion of the branch is exposed by the canker. Narrow wounds become larger eventually. Macuprox 16 W @ 2.24 kg/ha in 1120 lit of water should be sprayed in the affected stems or branches of the bushes.     

 

6. Collar Canker: The disease generally infects with wounds on the collar region of young tea plant. Plant is affected causing wilting and die back due to infection. Collar region becomes girdled. Formalin 40% @ 2.24 kg/ha in 1120 lit of water should be sprayed in the affected collar region of the bushes.

 

7. Charcoal Stump Rot: This is a cosmopolitan and primary root disease present in nursery and mature tea plantation. Some of the branches dry up and leaves become wilted, droopy, and flaccid but remain attached firmly to the braches. Formalin 40% @ 2.24 kg/ha in 1120 lit of water should be sprayed in the affected collar region of the bushes after forking the soil.        

 

Weed spectrum in Bangladesh tea and their control: As many as 37 weed species have so far been recorded. It is estimated that about 15-20% crop can be reduced due to weeds. These weeds can be controlled by manual weed control methods includes the practice of Sickling, Cheeling/Scrapping, Forking/Hoeing, or Hand weeding. Besides, Rapid weed control in a large area can be done by chemical weeding. For the control of Bagrakote, Mikania, Crab grass, Burmuda grass and other monocotyledonous & dicotyledonous weeds, BTRI approved Glyphosate @ 3.7 lit/ha in 750 lit of water should be sprayed.

 

Tea Processing: The following five steps are followed for the processing of black tea in our country:

1) Withering

2) CTC processing

3)  Fermentation

4) Drying/Firing

5) Sorting/Grading

 

Tea Economics: The role of tea sector in the economy of Bangladesh is undeniable. To make the tea industry to a profitable organization, it is important to achieve the standard quality by increasing per hectare production as well as reducing the cost of production. The cost of production of tea cultivation per hectare in first 5 years is Tk. 2,46,777 and the cost of production of 1^st year is maximum i.e. Tk. 1,07,283 and it will be reduced for the next years. The per hectare income from the green leaf excluding total production cost of the 4^th year and so on  gradually goes to the profits.  

 

For Bangla version please visit: http://www.ais.gov.bd/e-krishi/Cash crops/Tea

or "The Bangladesh Pratidin". Year: 1, Issue: 181, 18 September 2010. Dhaka.