Bud rot caused by the fungus Phytophthora palmivora is a disease prevalent during the monsoon season. High relative humidity and temperature favour the disease.

Palms of 10-20 years age are most susceptible while those above 40 years are not usually infected.

First visible symptom

In seedlings, the spear leaf turns pale and comes off with a gentle pull. In adult palms, the first visible symptom is the colour change of the spear, which becomes pale and breaks at the base and hangs down.

The tender leaf base and soft tissues of the crown rot into a slimy mass emitting a foul smell. The rotting slowly progresses downwards finally killing the palms. This is accompanied by drooping of successive leaves.

The development of young nuts ceases but the older ones may mature.

The disease proves fatal if not checked at the early stages, before damaging the bud.

Pest management

In the early stages of the disease, when the heart leaf starts withering, cut and remove all affected tissues of the crown.

Dress with Bordeaux paste and protect it from rains using a mud pot till normal shoot emerges. (To make 1 litre of Bordeaux paste, dissolve 100g of copper sulphate and 100g of quick lime each in 500 ml of water separately and mix together).

Burn all disease affected tissues. Give a spraying with 1 per cent Bordeaux mixture on spindle leaves and crown of disease affected neighbouring palms.

Provide adequate drainage in gardens and adopt proper spacing so as to avoid overcrowding of palms.

P. M. AJITH & P. MANJU

Department of Plant Breeding and Genetics,
College of Agriculture,
Velayani, Thiruvananthapuram