Nutmeg (Myristica fragrans)

Leaf fall in nutmeg (Phytopthora sp.)

Symptoms

  • The symptoms first appear as dark brown water-soaked lesions on the midrib of the leaves which enlarge and spread to leaf lamina resulting in blighting.
  • Affected petioles show black discolouration.
  • On young shoots, black lesions were observed which enlarged in size resulting in rotting and drying up of shoots from tip downwards.
  • Sometimes severe defoliation of green leaves could be observed in the affected gardens.
  • Immature fruit rot and fruit drop are highly prevalent in nutmeg gardens in Kerala.
  • Immature fruit split and shedding are found in some trees without any apparent infection.
  • Half matured fruits are most susceptible to this disease.

Management

  • Remove and destroy all fallen leaves and fruits.
  • Maintain proper spacing between plants at the time of planting.
  • Provide proper shade
  • Ensure proper drainage facilities during monsoon
  • Spray Pseudomonas fluorescens (20g/l) at monthly intervals during onset of monsoon.
  • Add trichoderma enriched cowdung as basal dose at the rate of 5-10 kg per tree