NAGPUR MANDARIN CULTIVATION

1. Selection of site for Citrus nurseries and orchards:

Well-drained medium deep soils should be selected for raising nurseries and orchards. However, very shallow and very deep soils should be avoided.

2. Raising of Citrus nurseries

  1. The seeds of resistant rootstock should be obtained from authentic and certified source.
  2. Medium sized, bold, dried root stock seeds should be treated with either Vitavex or Thiram dust before sowing in raised nursery beds.
  3. A long-term stagnation of irrigation water in nursery beds should be avoided to control the root diseases.
  4. Nursery plants should be sprayed regularly at monthly interval with Bavistin (1 g/L) as a prophylactic measure.
  5. If diseases caused by Phytophthora spp. are noticed in nursery plants, the affected plants should be removed from the nursery and either Ridomil MZ 72 @ 2.75 g/L or Aliette @ 2.5 g/L should be sprayed till run off at 40 days interval.
  6. Monocrotophos @ 0.5 - 1.0 ml/ litre or Quinalphos @ 1.0 ml/litre of water should be sprayed at weekly interval to control insect pests in nursery.
  7. At secondary stage before budding in addition to leaf miner and leaf eating caterpillar, Citrus psylla and mites need to be controlled. Application of Dimethoate @ 1.0 ml/litre or Dicofol 1.5 ml/litre should be sprayed at weekly interval.
  8. Nursery should be raised away from existing orchards to avoid disease and insect pests' problem.

 

2.1 Budding operations:

  1. Budding should be done from authentic and certified source of budwood.
  2. Budding should be done at a height of 10 - 12 inches.

3. Planting of orchard:

3.1 Pit size:

Pit of 2'61" x 2'60" size with a spacing of 6M x 6M should be dug to plant citrus plants preferably without soil ball to avoid the soil borne diseases and nematode problem.

 

3.2 Pro-planting treatments:

The root system of plant should be dipped in Ridomil MZ 72 @ 2.75 g/L + Bavistin 1 g/L solution for 10 - 15 min. before planting in the pits.

3.3 Planting

Bud union should be kept at least 6" above the ground while planting in field.

 

4. Nutrition:

4.1 Doses:

Age of plant

I year

2 year

3 year

4 year or above

N/plant

150 g

300 g

460 g

600 g

P/plant

50 g

100 g

150 g

200 g

K/plant

25 g

50 g

75 g

100 g

Note: - Preferably 1/3 recommended dose of nitrogen should be applied through organic manures like FYM, Cakes etc.

4.2 Application time and method

Non bearing trees:

  1. Nitrogen should be applied in split doses during April, August and November; Phosphorus in August and November and Potassium in November.

Bearing trees:

  1. Nitrogen should be applied in three split doses during April, August and November along with 200 g Phosphorus in two split doses in August and November and 100 g Potassium in November for Nagpur mandarin grown in black clay soil.
  2. Survey of mandarin orchards of Kalmeshwar and Katol tehsils of Nagpur district have indicated that most of the orchards were deficient in nitrogen. Around 50% orchards were low in leaf P and soil available P status, while leaf K and soil available K was observed to vary from optimum to high level. During the fruit development stage, leaf K may not be in optimum range, therefore some K should be applied. The supplemental dose of P @ 200 g/plant and K @ 100 g/plant should be incorporated in the fertilizer schedule of bearing Nagpur mandarin.

5. Weed control:

Pre-emergence herbicides, either Diuron 3 Kg ai/ha or Simazine 4 Kg ai/ha should be sprayed twice at 120 days interval from the last week of May for effective and economical control of dicot and monocot weeds in the orchard.

 

6. Control of Insect posts:

6.1 Blackfly:

Monocrotophos @ 1 ml or Phosphamidon @ 0.7 ml or Acephate @ 0.8 ml or Dimethoate @ 2 ml/L of water should be sprayed at first instar nymphal stage.

6.1.1 Spray technique:

Sufficient quantity of spray solution should be sprayed to cover the whole canopy, which depends on age and size of the plant.

Spraying should be done by keeping the nozzle of the sprayer facing the under surface of the leaves at the base of the canopy and should be carried upwards slowly till the middle of the canopy from where it should be brought back to the normal position to cover the top portion of the canopy.

All the time first spray should always be followed by second spray at 15 days interval for achieving better control. However same insecticide should not be repeated in the next immediate spray.

Precautionary measures:

  1. Water logging should be avoided in the orchards.
  2. Proper drainage should be maintained.
  3. Close spacing between plants should be avoided while establishing new orchards. In case of already established orchards, the intermingling branches should be pruned.
  4. Collateral host plants of blackfly such as guava, sapota and pomegranate should as far as possible is avoided in the vicinity of citrus orchards. In case of already established orchards, chemical control measures should also be carried on these plants along with citrus orchards.

6.2 Mites:

Dicofol @ 1.5 ml/L of water should be sprayed followed by wettable sulphur @ 1.5 g/L of water at weekly interval.

6.3 Psylla:

Phosphamidon @ 0.3 ml or Quinalphos @ 1 ml or Thiometon 0.1 ml/L of water should be sprayed at weekly interval.

6.4 Leaf miner:

Monocrotophos @ 1 ml or Quinalphos @ 2 ml or Phosalone @ 1. 5 ml/L of water should be sprayed at 10 days interval as soon as the leaf miner infestation is noticed. At every 45 days interval one spray of synthetic pyrethroid like fenvalerate @ 0.5 ml/L of water may be given.

 

7. Management of orchard diseases

7.1 Twig blight:

Pruning of dead/dried twigs after harvest of crop about 2 cm below the dead portion and two sprays of either Bavistin or Benomyl (1g/L) at monthly interval to cover the whole canopy at run off stage controls the problem.

7.2 Gummosis /root rot /collar rot

  1. The diseases caused by Phytophthora should be confirmed through any research station.
  2. The affected plants should be sprayed and drenched with Ridomil MZ 72 (2.75g/L) or Aliette (2.5g/L) followed by another treatment after 40 days.
  3. As a prophylactic Measure, orchard should be sprayed by the above fungicides every year twice before the start of monsoon and after 40 days of first spray covering trunk and basin of the plants.

 

Precautionary measures:

  1. Flood irrigation should be avoided.
  2. Irrigation water should not be allowed to stagnate for a long period and contact of water with the trunk should be avoided. Double ring type basin should be made.
  3. Infestation of bark eating caterpillar should be controlled to avoid injuries to the trunk.
  4. Deep under - canopy ploughing should not be practiced to avoid injuries to root system and subsequent infection.

8. Management of Post-harvest diseases

8.1 pre-harvest fungicidal sprays:

Three pre-harvest sprays of either Bavistin or Benomyl (1g/L) at 15 days interval before harvest can control more than 70% post- harvest decay up to three weeks at ambient condition and 54% pre- harvest fruit drop in the field.

8.2 Post-harvest fungicidal treatment

Post-harvest dip of Nagpur mandarin in the solution of either Bavistin or Benomyl (1g/L) for 5 min. can control 70% post- harvest decay up to three weeks at ambient condition.

Precautionary measures:

  1. Bearing plants should be kept healthy by following the recommended schedule of plant protection measures.
  2. Smooth handling of the fruit after harvest to minimize the injuries and bruising is must in order to get desirable results.
  3. Copper fungicides should not be sprayed as pre-harvest treatment.

 

9. Harvesting, handling and storage:

  1. Harvest the fruit by clipping or snapping smoothly without injuring neck/collar of the fruit or making buttonhole. If clipped, keep small button close to the peel. Spot - picking is recommended for the fruit with minimum 3/4 surface yellow-orange colour having TSS: acid ratio not less than 14 for Ambia crop and 20 for Mrig crops. TSS content should be minimum 10% for both the crops. Don't delay harvesting for colour development once the TSS acid ratio is achieved. Otherwise fruits may get puffy.
  2. Avoid handling of fruit on orchard ground covered with straw and don't expose fruit directly to the sun.
  3. Packing is recommended as soon as after the harvest.
  4. If fruit is to be waxed, the packing line is recommended for washing, waxing (Stayfresh high shine wax 2.5% + Bavistin @ 4g/L wax) and size grading for large -scale operation.
  5. For small quantity (1 to 1.5 ton), short term (20-25 days) storage at farm, evaporative cool chamber is recommended for better returns.
  6. For on-tree storage to extend harvesting and marketing period, trees should be treated with two sprays of gibberellic acid (10 mg /L) at 15 days interval commencing from colour break stage (development of yellow-orange spot on green fruit).
  7. For long term refrigerated storage, maintain 6- 7˚C temperature and 90-95% RH. Don't lower temperature to 4˚C due to likelihood of chilling injury. Avoid storage beyond 45 days.