Rubber (Hevea brasiliensis)

Abnormal leaf fall (Phytophthora meadii)

Symptoms

  • Abnormal leaf fall occurs during June-August, while general leaf fall occurs during December-January
  • The conspicuous symptom is the formation of coagulated latex at the point of entry of the pathogen.
  • A dark brown discoloration of the petiole
  • Petiole infection results in premature defoliation.
  • The leaves may sometimes remain attached to the petiole.
  • Bronze coloured discoloration of the young foliage.
  • Circular brownish water soaked lesions appear on the leaf lamina.
  • Several of the lesions coalesce together causing rotting of the tissues
  • During south west monsoon period, the fruits rot.

Management

  • Prophylactic spraying of the foliage prior to the onset of southwest monsoon with 1 per cent Bordeaux mixture (3000-4000 l/ha) or oil based copper oxychloride (30-40 litres of COC-oil mixture per ha mixed in 1:5 proportion) is recommended.