Mahali (Koleroga or Fruit rot)(Phytophthora palmivora)

Symptoms

• The disease results in rotting and excessive shedding of immature nuts from the trees during south west monsoon.
• The water soaked dark green or yellowish spots initially develop at the stalk end or base of the nut.
• The lesions gradually spread covering the entire nuts which rot and shed in large numbers.
• A felt off white mycelial mass envelopes on entire surface of the fallen nuts.
• Fruit stalks and rachis of inflorescence are also affected.
• Nuts show large vacuoles and are lighter in weight.
• Dark brown radial strands on kernel make them unfit for chewing.
• Under severe infection the top of the affected trees dries up resulting in withering of leaves and bunches leading to bud rot symptoms

Management

• Adopt clean cultivation.
• Destroy completely affected trees.
• Collect and burn fallen nuts.
• Remove and destroy all completely affected inflorescence and immature bunches.