Report of diagnostic field visits of Khasi mandarin orchards in East Khasi Hills District

Pankaj Baiswar, D.M. Firake and H.D. Talang

 

A team of Scientists (Dr. Pankaj Baiswar, Dr. D.M. Firake and Dr. H.D. Talang), ICAR Research Complex for NEH Region, Umiam and Officers from Department of Horticulture, Govt. of Meghalaya visited Khasi Mandarin orchard at Nohwet and other adjoining villages of East Khasi Hills district on the 13th November 2017. The purpose of the visit is to know the condition of the Khasi Mandarin orchard maintained by the farmers themselves. The major finding are as follows:

  1. Orchards status: The orchards were poorly maintained by the citrus growers. Average age of orchard was 10 to above 25 years old. On the basis of the questioners it revealed that the frequency of visiting the orchards by the farmers was very less; only once in a year, i.e. during the month of October – November, before the harvesting. 
  2. Lack of training and pruning: Most of the plants have multiple shoots, crisscrossed braches and so much of water suckers because no training and pruning are being adopted by farmers. Not even the disease infected branches were pruned from the tree. 
  3. Planting materials are of unknown source: In all the existing orchards, seedlings used as planting materials were procured from market or nursery without any certification. When budded or grafted plants were used, no removal of the shoots arising out of the rootstock was done which hamper the growth of the plants and ultimately fruit quality.
  4. No fertilizers and manures application: Fertilizer and manuring was not completed in orchards
  5. No soil and water conservation measures adopted: Most of the roots of fruit trees were exposed because no soil and water conservation techniques were undertaken. Moreover, orchards are located in the steep hill and rocky slope with shallow soil.
  6. No weed management: The orchards were infested with several types of weeds such as climber weed, Mikania scandens

Recommendations: on the basis of the above observations, following are the recommendation for improving the Khasi mandarin orchard

  • In the first year, all branches growing upto 50-70 cm above the ground must be removed. The stem must be kept clean and straight with 4-5 well arranged branches in all direction of the tree. All the undesirable branches including water suckers emerged from the seedling and rootstock should be frequently removed as and when they appear on the tree. In bearing trees, pruning was required to remove undesirable growth such as water shoots, criss-crossed, dried, diseased branches. This should be carried out once in a year after harvesting of fruits during December-January. The cut end portion of pruned part must be pasted with bordeaux paste (in case not available, simply paste with cowdung).
  • Disease free (seedlings, grafted or budded) planting materials should be procured from the recognized/ registered nurseries.
  • Manure and fertilizers should be applied to the Khasi mandarin orchard and following schedule may be followed.
Manure/ Fertilizers Time of application

Age of tree (year)
1st 2nd 3rd 4th 5th 6th
FYM (kg) Feb-March - 5 10 15 20 25
Urea (g) March 100 150 200 250 300 350
SSP (g) March 100 200 300 400 500 600
MOP (g) March 50 100 150 200 250 300
Lime (kg) Feb. - 1 2 3 4 5

The time of manure and fertilizers application is June-July and September – October. Fertilizers and manure must be apply around the basin under the canopy of the tree, keeping 20-25 cm space from the main stem and mix by light hoeing. About 2-3 sprays of Zinc Sulphate (0.4%) + magnesium Sulphate (0.2%) + Copper Sulphate (0.3%) or Multiplex (mixture of multimicronutrient @ 0.25%) may also be given during flushing period.

  • Half-moon terrace may be prepared at the basin of the trees to minimize soil erosion during rainy season. Similarly organic mulching should be done at the basin of the trees which will conserve moisture and maintain the nutritional status of the soil.
  • The orchards may be kept weed free, particularly the tree basin to avoid competition for space, nutrient, water etc. to the Khasi mandarin plants.

Diseases:

  • New flushes should be protected from scab and powdery mildew by spraying Bordeaux mixture (1%) during Feb-March, June-July, Sept-Oct.
  • Clean the gum oozing wounds on the trunk and main branches and apply Bordeaux paint for managing Gummosis/foot rot.
  • Multiply Trichoderma in FYM (mix 1 kg of Trichoderma formulation in 100 kg of well decomposed FYM, keep it for 10 days under polythene cover, mixture should be turned every three days - this will be sufficient for around 1 acre) and use this FYM in the orchard. This will help in managing soil borne pathogens.

Diseases:

  • New flushes should be protected from scab and powdery mildew by spraying Bordeaux mixture (1%) during Feb-March, June-July, Sept-Oct.
  • Clean the gum oozing wounds on the trunk and main branches and apply Bordeaux paint for managing Gummosis/foot rot.
  • Multiply Trichoderma in FYM (mix 1 kg of Trichoderma formulation in 100 kg of well decomposed FYM, keep it for 10 days under polythene cover, mixture should be turned every three days - this will be sufficient for around 1 acre) and use this FYM in the orchard. This will help in managing soil borne pathogens.

Insect-pests:

  1. Clean cultivation: regular removal of weeds and alternate host plants of citrus pests in and nearby the orchards
  2. Regular clipping and destruction of infested plant parts.
  3. Regular monitoring and killing of larva of borers and bark eating caterpillar by inserting wire inside the tunnel or insert cotton, swabbed with kerosene or petrol, in the hole and seal the hole with clay.
  4. Spray of neem oil @2ml/litre with sticker or surfactant @0.5ml/litre, as and when infestation of aphids started.
  5. Use of liquid formulations of biopesticide, Verticillium leccani @ 5 ml.litre water twice at fortnightly interval during Feb.- March, June- July and Sept.- Oct. effectively reduces aphids, black flies, leaf miners, scales and psylla.
  6. Ant colonies in the orchard should be destroyed as they are the carrier of mealy bugs and scales to their feeding sites.