The aerial branches get infected at any point. At the site of infection of branch, the discoloration occurs and rotting progress upwards and downwards resulting in die-back symptoms.
The lateral branches of the affected vines break off at the nodes and fall off.
b. Foot rot or Collar rot:
The stem near the ground level get infected and the rotting and death of vine occurs within 2-3 weeks.
The affected portion emits bad odour. The necrosis progress down wards to the underground stem and to the root system.
c. Root rot:
The infection starts at main root or at feeder root. The leaves become yellow and defoliate.
Management
Selection of healthy nursery material.
Provide good drainage.
Soil drenching with 1% Bordeaux mixture after removal of the affected plant.
Spraying with Copper oxi chloride @ 4 gram per litre of water.
Soil application of neem cake and Trichoderma viride or P. fluorescens
Dept of Agriculture Development 
SFAC Kerala