Advisory for hailstorm affected citrus orchards

Nagpur: In recent weeks (during second week of February 2018.) several Vidarbha districts were lashed by hailstorms and rains. Several villages across Vidarbha are severely affected with unseasonal rains and hailstorm. Nagpur, Wardha, Amravati, Washim, Yavatmal, Akola, Buldhana where citrus viz. Nagpur mandarin (Santra) Mosambi sweet orange and acid lime (nimbu) are grown are worst affected. This hailstorm has occurred in Marathwada areas also where Mosambi orange is badly damaged.
Due to hailstorms trees have been defoliated and hails have hit hard on the twigs and branches thus causing injuries. These injuries may invite secondary infection in coming days. Citrus growers are advised to take following steps immediately.

1) Apply copper oxy chloride / Blue copper (3 gram per litre of water) or Bordeaux mixture (1%) to thoroughly drench the trees (Approximately 10-15 litre solution per grown up tree).

2) If injuries are big on stems and branches prepare a Bordeaux paste and apply on the injuries.

3) After a week, apply second spray of carbendazim (1 gram per litre) + Aliette (2.5 gram per lit) to thoroughly drench the trees.

4) Foliar application of gibberellic acid (GA) @ 1 gram and urea 1kg per 100 litre of water may be given at earliest in this month i.e. March.

5) This is also a time to apply fertilizers to trees (200g N + 200g Phosphate + 100g Potash) because new growth or flush is emerging in spring season. As per recommendations, apply fertilizers, mix in the soil and watering should be done immediately.

6) Readily available mixture of micronutrients may also be applied to trees in April last week when new leaves almost fully develop as per prescription given on packets. Otherwise, take micronutrient powders such as zinc sulphate, manganese sulphate, ferrous sulphate (2 grams each separately in one lit water) + borax (1 gram) + urea (10 gram) + slaked lime (5 grams) and dissolve in one litre of water. Sufficient spray should be applied to cover entire tree.

7) Now summer has started, apply sufficient water to trees through irrigation.

8) It is also a right time to remove dry twigs in Mrig crop trees if crop is harvested. These dry twigs harbour pathogens. Therefore, take 2-3 centimetres of green portion below the dry portion and prune these dry twigs and branches. Immediately after that, apply copper oxy chloride spray or Bordeaux mixture (1%) as given above. After 1 week follow spray of carbendazim + Aliette as given above.

9) Remove rotten and fallen fruits and debris, twigs and leaves from the orchard floor immediately and bury them in a pit and cover with soil.

10) Method to prepare Bordeaux mixture (1%) : Take one kilo each of copper sulphate and lime separately. Soak in five litre of water overnight in two separate plastic containers. Stir thoroughly with a wooden stick so that copper sulphate and lime are dissolved completely. Take third separate plastic container and pour copper sulphate and lime solutions and mix thoroughly. Filter the mixture through two layers of fine muslin or any other cloth. Check copper content of the spray solution by dipping blade/knife. If copper deposit appear on blade then add little more lime solution in to Bordeaux solution. Lime is added to make Bordeaux mixture neutral. Make the total volume 100 litres by adding about 90 litres of water. This is 1% Bordeaux mixture which is used for spray.

11) Bordeaux paste can be prepared similarly as given above except addition of 90 litres of water.

This paste is thick in consistency because there is not much water and hence applied with brush on cut/ injured surface of the trees.