Wednesday, July 22, 2009

Rejuvenating an orchard infested with Nematodes

Rejuvenating an orchard infested with Nematodes.

After applying almost all synthetic insecticides (Carbofuran, Carbendazim, Ridomill, Contaf and Bourdeux Mixture,.. to name a few) and with no remedy to cure root rot and yellowing of leaves in his orchard, a farmer friend approached me for advice, even though I am not a professional agriculture consultant. Top soil and sub soil at second feet were sent for soil test analysis. Test revealed heavy infestation of Nematodes.

About Nematodes:
They are migratory endoparasites which can survive in soil for 13 months without host plants. So, a minimum of 3 summer ploughs effectively suppresses the nematode population.

Nematodes complete their life cycle in 20 -25 days in the roots of the host plants. They invade at any portion of the root causing severe root damage resulting in poor water and mineral uptake by the plant.
  • Usage of biological agents such as Paecilomyces a bionematicide, Trichoderma Viridi and VAM are recommended to control nematodes.
  • Use of press mud @ 2 tons/acre in the field and application of Neem cake 500 gms per plant helps in suppressing the nematode population.
  • Crop rotation with Paddy, Sugarcane, green gram, sunhemp, cotton Etc., helps inreducing nematode population.
  • Growing antagonistic plants namely Tagets erecta (Tamil: Sendu malli, Sevanthi and Thulukka Samanthi) Crotalaria juncea (Sunhemp) as an inter crop in the field drastically reduces the nematode population.
Observations at our friend's orchard: Soil is lateorite and without organic matter. Root zone is affected by Nematodes and fungal pathogens. There is defoliation, debility, and dieback of leaves. Basin management is not proper. Micronutrients deficiency. Stray population of Mealy bugs noticed.

Remedial Measures suggested:

  1. Soil and phytosanitory management.
  2. Formation of bund around the plant. Apply adequate quantity of peat soil. Ensure that there should not be any water stagnation around the plant.
  3. Apply well-composted cow dung 4 Kgs + 250 gms of Neem cake + 250 gms of Pungan cake around the basin.
  4. Mix Pseudomonus 25 gms/plant + Trichoderma Viridi 25 gms/plant + Paecilomyces 25 gms/plant and apply it around the root zone of the plant.
  5. Spread leaf mulch around the basin.
  6. Growing Sunhemp as intercrop.
Then, after 15 days,
  1. Prepare 1 Litre Pseudomonus + ½ Kg Starter + 200Litres of water and mix it daily for 5- 6 days for fermentation.
  2. Prepare P.G.P.R 1 Kg + ½ Kg Starter + 200Litres of water and mix it daily for 5- 6 days for fermentation.
From the above preparations:
  • Take Sl.No.1 – 1 Litre and Sl.No.2 – 1 Litre and apply around the root zone of the affected plant every 15 days. Repeat the same for 3-4 times.
To control sucking pests and White flies:

  • Neem Kernals 5 Kg crushed and choked in 5 Litres of water for 2 days. From the above prepared solution take 2 ½ litres and mix it in 400 Litres of water and add 1 Kg Beauvarium + 1 Kg Verticillium + 1 Kg Jaggery stir them well and spray it (Foliar) on the plant.
To overcome Zn and Mn deficiency apply ZnSo4 and MnSo4 6 Gms each / plant.

Our friend strictly followed all the above suggestions, endured the agony of waiting for 3 months to see the final encouraging results.

Yellowing of leaves stopped, fresh green shoots appeared, root rot disappeared, consecutive soil test revealed a significant reduction of nematode population, and finally with a smile on his face, our friend who used to criticize organic cultivation practices, is now an organic farmer.

Vishnu Sankar

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