Cultivar: Khasi Mandarin (Local)

The time of planting is May to August

Soil : Mandarin thrives well in deep lose well aerated soil devoid of any hard pan. Ideal pH range for mandarin is 5.5 to 7.5. It is also highly sensitive to moist soil conditions.

Propagation:
1) Seed
2) Budding
1. Seed: Since seeds of mandarin are mostly polyembryonic, the nucellar seedlings obtained through the mother plant, thus enable to retain the clonal characters as in vegetable propagation.
Seeds should be sown first in
(a) primary nursery and then seedlings should be transferred to the
(b) secondary nursery.
(a) Primary nursery: The site for the primary nursery should be selected on high land in light soil with good drainage. Raised seed beds of 20-30cm x 1m x 5m size should be prepared with a mixture of well decomposed cowdung, soil and sand at a ratio of 1:1:1 respectively. Seed from healthy and vigorous mother trees with uniform and good bearing capacity should be collected. The mother plant should preferably be 20-30 years old. Freshly extracted seeds should be washed and dried in shade. Seeds should be dibbled at 2.5cm. between the rows and 1.25cm within rows at a depth of 0.5 to 1.25cm. Adequate watering should be done at regular interval.
(b) Secondary nursery: Seedlings at 4 to 6 leaf stage should be transplanted from the primary nursery to the secondary nursery bed. The seedlings should be transplanted at 30cm between and within the rows. Side sprouts should be regularly removed. Regular control measures against pests and diseases are essential. Seedling of 3 years is ready for transplanting.
2) Budding: T or inverted T (A) budding is the best budding method for Khasi Mandarin:
(a) Root Stock :
1. Rough Lemon.
2. Rangpur Lime.
3. Cleopatra Mandarin.
4. Trifoliate orange.
(b) Rootstock Seedlings:
The rootstock seedlings are ready for budding within 11/2 to 2 years.
(c) Scion or bud-wood: Scion or bud-wood should be collected from known productivity, vigorous, healthy and insect and disease free trees with a regular bearing habit. The best time of budding is September and February.
(d) Budding method: Budding should preferably be done at a height of about 20-25 cm from the ground level. First a vertical cut (about 2 cm long) is made using a sharp budding knife in the stock plant. Then a horizontal cross cut at the top or bottom of the vertical cut is made as per ‘T’ or ‘-’ method through the bark about 1/3 rd the length around the stock. Then the flap of bark is opened by the knife for insertion of the bud. After making the proper cut in the stock plant, the shield piece is cut out of the bud stick. A shield shaped piece of bark containing the bud from 1 to 2 cm in length is removed from the bud stick including a thin silver of wood on the cut side.
Then the shield is pushed under the two raised flaps of bark of stock until it is well covered by the two flaps of bark keeping the bud exposed. The bud union is wrapped using transparent polyethylene sheet. This can be unwrapped after 6-8 weeks of budding,. After success of the budding, just before new growth begins the root stock is cut off immediately above the bud. The budded plants are ready for transplanting within 6-9 months.

Micronutrient:
Foliar application of micro nutrient viz. Zn, B and Mo is very much effective, @ 0.02%, 0.05% and 0.05% as ZnSO4, Borax and Ammonium-molybdate respectively thrice in a year during Feb-March, June-July and Sept-Oct.

Orchard Management:
Weeding should be done from the month of April; first by hoeing followed by spray of Glyphosate a.i. @ 1 kg/ha after 60 days followed by another hand weeding after 60 days of chemical spraying.

Intercropping:
Summer green gram/cowpea followed by toria as intercrop up to bearing stage and alternatively pineapple can be grown successfully as intercrop.

Plant Protection for Citrus:
(1) Trunk borer: It is a very damaging insect pest of mandarin orange in Assam. The grub bores hole into the tree trunk near the base and makes tunnel through the pith upward and the plant eventually dies. Prophylactic smearing of carbaryl or monocrotophos or quinalphos with lime and water (1:1:25) should be applied upto one metre from the base of the tree during March/April which prevents the adult from laying egg. Once the hole is made, it should be spiked with wire to kill the grub and then the hole should be cleaned and plastered with wet soil. Alternatively to kill the insect the hole should be plugged with cotton/cloths soaked in insecticides like dichlorvos (0.07%) or phosphamidon (0.05%) and then plastered with mud to have an airtight condition. Proper pruning and training are also essential to minimize the infestation.
Prophylactic smearing with lime solution (1kg/10lt. of water) along with 50ml monocrotophos and gum applied upto 1m from the base of the trees during March followed by injection of either 10ml petrol or dichlorvos 0.05% or monocrotophos 0.07% into the holes and sealing with mud and cowdung plastering for effective control of Trunk borer.
(2) Shoot borer: The shoot borer damages mostly young and new shoot of the plant. The grubs bore into the tip of the new shoot and make tunnels through the pith of the branch from top to bottom and the shoot dies due to infestation. The insect starts damaging from March to October. The insect can be controlled by pruning and burning the infested branches. Then smear Bordeaux paste with Nuvan in the cut portion. The insect can also be controlled by giving regular spraying with Monocrotophos (0.04%) i.e. 0.4ml in 1 litre of water) or phosphamidon (0.03% i.e. 0.3ml in 1 litre of water) starting from March to October at an interval of 20 days.
(3) Bark eating caterpillar: The insect damages the bark of the plant and as a result the flow of nutrients is stopped and ultimately the plant dies. It is a serious pest in neglected and old orchards. Removal of webbing followed by painting or spraying with monocrotophos 0.04% (0.4ml in 1 litre of water) on the infested portion of the bark can control the insect.
(4) Leaf miner: The larvae usually mine the undersides of new leaves making serpentine mines which are silver coloured because of entrapped air. Due to mining the leaves become distorted, curled and defoliation occurs during severe attack and the plant becomes stunted in growth. Two sprays with monocrotophos (0.4% i.e. 4ml in 1 litre of water) or phosphamidon (0.03% i.e. 0.3ml in 1 litre of water) during flushes have been found effective in controlling the insect. First spray should be given during initiation of new flush and the second after 20 days of the first spray.
(5) Lemon butterfly: The caterpillars feed on the leaves and defoliate the branches. Hand picking of larvae, with spraying with Sevin (0.1% i.e. 1ml in 1 litre of water) may be helpful in controlling the insect.
(6) Fruit sucking moth: The insect sucks the juice of the fruit and the fruits drop within few days. Destruction and disposal of fallen fruits and baiting with malathion 50 EC (0.1% i.e. 1 ml in 1 litre of water) with molasses (1%) and fruit juice help in controlling this insect.
(7) Scales, mealy bugs, aphids and psylla: These are sap sucking insects; Scales are brown tiny insects and are immobile. While sucking plant sap mealy bugs secrets honey dews on which sooty mould develops. Mealy bugs also cause fruit drop. The aphids infest the lower surface of the tender leaves, shoots and young fruits due to which the infested twigs are curled and the plant becomes sickly. The nymphs of psylla suck the cell sap from tender shoot, leaves and flowers causing curling, defoliation and drying of twigs. To control these insects spray monocrotophos (0.025% i.e. 0.25ml in 1 litre of water) or phosphamidon (0.035% i.e. 0.35ml in 1 litre of water) or malathion (0.1% i.e. 1ml in 1 litre of water). Repeat the treatment and when necessary.
(8) Gummosis or phytophtora foot rot: Phytophtora disease produces symptoms of declining health of citrus trees causing rotting of roots, girdling of the tree trunk and defoliation. The first symptoms are dark staining of the bark followed by olive brown in colour with a water soaked appearance. In advanced stage, the bark cracks, strips off lengthwise as in dries and gum starts exuding particularly in the late spring resulting into yellowing and die back. At the early stage, the affected portion should be scraped with a little extra healthy tissue without injuring the wood and then smear Bordeaux paste or Bordeaux paint (1:2 linseed oil).
(9) Wither tip: Wither tip or dry-up twigs from top to the bottom is a serious problem in citrus. Pruning followed by spraying of 1% Bordeaux mixture after harvest of the fruit control this disease. Twig blight or wither tip or dry-up twigs can be effectively managed by pruning in the month of January/February followed by two sprays with Copper oxychloride (COC) @ 3g/litre at 30 days interval or Pruning followed by one spray with COC @ 3g/litre + one spray after 30 days with carbendazim @ 1g/litre.
(10) Scab: The scab lesions appear as minute water soaked round spots which enlarge slightly, turn brownish and then corky on fruit, leave and young twigs. Removal of infected leaves, twigs, fruit and spraying of Bordeaux mixture (1%) or copper oxychloride 50WP (0.3% i.e. 3g in 1 litre of water) or Mancozeb 75 WP (2 g/l) have been found effective in controlling the disease.
(11) Canker: It is a bacterial disease. The canker lesions appear as minute water soaked round spots, enlarge slightly, turn brownish, corky which can be controlled by 1% Bordeaux mixture or Streptocyclin 100 ppm + copper oxychloride 0.3% (3 g in 1 litre of water) spraying during new flushes.
(12) Greening: The infected plant shows chlorosis of leaves, thickening of leaf blade, shortening of twigs internodes, off-season blooming, leaf shedding and die-back. To control this disease, insect vector psylla should be first controlled (see psylla control).
(13) Twig Blight: Pruning in the month of January/February followed by 2 sprays of carbendazim 0.1% and thereafter 2 sprays of Copper oxychloride 0.3% (3 g in 1 litre of water) at monthly interval can control. (14) Pre harvest stem end rot: Four sprays of carbendazim 0.1%( 1 g in 1 litre of water) at monthly interval from May i.e. after fruit set to control fruit drop due to pre-harvest stem end rot.

Other Maladies:
1. Zinc deficiency: Zinc deficiency is considered as the most wide spread and damaging micronutrient deficiency of citrus. Deficiency symptom develops only in the new growth. The leaves are small sized, chlorotic crowded on shoot stems giving a bunched appearance, mottling, twig die-back and ultimately the tree starts declining. It can be controlled effectively by foliar spray of 0.4 to 0.6% (4 to 6 g in 1 litre of water) Zinc sulphate during new flushes.
2. Moss: Remove the mosses mechanically by rubbing with gunny bag.
3. Loranthus: The group of parasitic plants should not be allowed to develop on branches. It should be controlled by efficient pruning.
4. Fruit drop. Spray 10 ppm Planofix (1 ml in 4.5 lit water) or 2,4-D @ 25 g/100 lit of water immediately after flowering and again after one month. 3 sprays of 0.1% Carbendazim along with 30 ppm NAA starting from May onwards i.e. after fruit setting at bimonthly interval also can control fruit drop. Suggestions for Improvement of Citrus-Decline
1) Proper drainage should be provided to drain out the excess water from the root-zone.
2) For vegetative propagation the mother plants should be ascertained of their freeness from virus and mycoplasma diseases.
3) It is advisable to establish new orchard with budded plants on resistant root stocks.
4) Regular manuring of both non-bearing and bearing trees is essential.
5) Foliar feeding of micronutrients is essential as a regular practice.
6) Cultural practices like regular weeding, intercropping with only short duration, shallow rooted legume crops upto pre-bearing stage are suggested.
7) Pruning of dead and dried twigs, removal of plant parasites like loranthus etc. are desirable practices.
8) Soil working near root zone should confine only upto 10 cm soil depth.
9) Application of Bordeaux paste may be practised regularly to a height of about 50 cm of the trunk from the ground level.
10) Pest and disease control measures should be followed strictly.

Planting:
Before monsoon, pits of 0.75m x 0.75m x 0.75m size with a spacing of 5m x 5m are prepared and then refilled with soil-manure mixture (1: 1) and then allowed to settle.
The time of planting is May to August.
The plant is set at the centre of the pit and the soil around is compacted. Mulching with dry leaves should be done. Plants should be irrigated regularly at fortnightly intervals during dry periods.

Pruning and Training:
Schedule for rejuvenation of declining Khasi mandarin orchards:
1. Pruning and Training
Unwanted, diseased and pest infected branches and twigs are to be removed by pruning and training during January/ February.
2. Correction of soil pH
Applying of 1 kg Agricultural lime per plant for three years during January/ February and then mixed thoroughly with soil by light hoeing.
3. Integrated nutrient management
Application of nitrogen (N), phosphorous (P2O5), and potash (K 2O) @600g, 300g and 600g per plant along with 7.5 kg. Mustard oil cake in two splits is to be done during March/April and Sept/Oct. Zn @ 2.5 g, B @ 0.6 g and Mo @ 0.1 g per plant are also to be applied along with NPK. Apply foliar spay using Green Harvest Crop Booster @ 25 g with 50 g Zinc Sulphate and 100 g Urea in 10 lit water.
4. Integrated management of Phytophthora foot rot, twig blight and stem end rot

For control of Phytophthora foot rot, soil drenching and spraying of tree trunks with Mancozeb + Metalaxyl (Ridomil MZ-72) @ 0.2 %(2g in 1 litre) followed by Bordeaux mixture (1%) during Feb-March and July-August.
Following pruning and training in January, 2 sprays of Carbendazim (0.1%) i.e., 2g per lit. of water followed by two sprays of COC (0.3%) i.e., 3g per lit. of water at monthly interval for control of Twig blight.
Four sprays of carbendazim @ 0.1% i.e., 1 g per lit. of water at 60, 80 and 120 days initiating from May onward for control of Pre harvest stem end rot.
5. Integrated management of trunk borer and bark eating caterpillar
Prophylactic smearing of 50ml endosulfan + 1 kg lime in 10 litres of water along with gum up to 1 meter from the base of the trees during March every year to prevent adult from laying eggs.
Afterwards 10ml petrol is to be injected into the holes of trunk borer and holes are sealed with mud and cowdung plastering. 6. Integrated weed management
Light hoeing before application of fertilizers during March followed by glyphosate 41 SL @ 1 lit./ha spray on the resurgent weeds during May followed by hand weeding at bimonthly interval.

In the first year of planting no fertilizer is applied to the plant. For bearing plant, apply Neem cake @ 7.5 kg per plant per year.
Manures and fertilizers should be applied in two split doses, i.e. February/ March and September/October.
Fertilizer should be applied leaving about 15-45 cm space around the tree trunk and well beyond the canopy spread. Immediately after application of fertilizer, it should be incorporated into the soil by light or shallow hoeing.

Integrated Nutrient Management (INM):
75% recommended dose of fertilizers i.e. 450 g N, 225 g P2O5, 450 g K 2O and 5.625 kg Neem oil cake along with VAM 500g, PSB 100g, Azospirillium 100g and Trichoderma harzianum100 g are to be applied per plant per year in 2 splits i.e. in March/April and September/October. The required amount of biofertilizers is to be mixed together with 10 kg FYM and should be applies 15 days before the application of inorganic NPK.

Harvesting:
After 8-10 years, the seedling trees start bearing. Harvesting should be done by using ladder. Fruits should be collected in a bag and gently placed on a gunny carpet. Subsequently, they should be packed in baskets or cartoons for transportation to the market. About 800 to 2000 fruits per plant per year can be obtained from a 30-40 years old orchard.

Benefit: cost ratio:
3.30 after 7-8 years
5.60 after 10 years