Exudation of the reddish brown liquid through the growth cracks mostly at the basal part of the trunk and bleeding patches higher up in the trunk are characteristic symptoms.
One or more lesions, lying close by, may coalesce to form large patches.
The liquid that oozes out dries up and turns black.
The tissues beneath the bleeding points decay and become yellowish.
The lesions spread upwards as the disease progresses. In advanced stages, the leaf size reduces leading to reduction in crown size.
The rate of leaf production slows down.
The production of bunches is affected and nut shedding takes place.
The trunk gradually tapers towards the apex.
The progress of the disease is faster during July to November.
Severe summer followed by heavy rainfall, water stagnation, nutrient deficiencies, and increased acidity (sourness) are conditions that favor the onset of the disease.
Management
Chisel out completely the affected tissues and paint the wound with Bordeaux paste.
Destroy the chiseled materials by burning. Avoid any mechanical injury to trunk.
Apply neem cake @ 5 kg per palm in the basin along with other organics.
Swabbing the lesions on the trunk with a paste of
Trichoderma viride talc based formulation (100 g 100 ml-1) along with application of lime or dolomite @ 1kg palm-1 during April-May and application of neemcake (5kg palm-1) + organic manure enriched with Trichoderma viride (1%) during September-October.
