Regeneration Status and Identification of Heart Rot Disease of Pasur (Xylocarpus Mekongensis) Tree in the Sundarbans of Bangladesh

Abstract

Regeneration status differs place to place and species to species in the Sandaracs. It depends on the different ecological conditions of the Sundarbans. The locations are Baniakhali, Chunkuri, Kalabogi, Kasiabad, Bojboja and Supati. Number of trees, seedlings up to 3 years and saplings above 3 years of all major species were recorded in each plot. The highest regeneration were recorded at Baniakhali 76997 per/ ha, 37333per/ ha at Supati and lowest at Chunkuri 34666 per/ ha. Pasur (Xylocarpus mekongensis) is a valuable timber yielding and highly useful tree species in the Sundarbans. It has great commercial value. It is found mainly in the saline areas on the North-Western part of the Sundarbans in association with other mangrove species. Pasur, a commercially valuable deciduous multipurpose tree species is affected by heart rot problem. As a result, it is characterized by the gradual death of the crown starting first with small twigs and then gradually larger branches die and lignin portion of the stem becomes useless. Heart rot is generally regarded as a condition locally known as “dhor.”. The fruit body, gall and cankers are developed on the different portion of the standing trees. It was observed and enumerated heart rot infestation status of different locations in the Sundarbans. It is affected (Less than 50% top dead and more than 50% top dead or heart rot (Dhor observed) severely at Kalabogy, Baniakhali and Bozbosa are heavily affected in the moderately saline water zone. The result shows that the percentage is 64%, 62% and 60% respectively. Then followed by Kasiabad 54% and Chunkuri 48%. Very low number of trees are affected at Supati covering 17% in the fresh water zone of the Sundarbans. The factors which causing the diseases are very difficult to identify. The International Mycological Institute, UK, confirmed two fungal pathogens. They identified two fungal pathogens for causal organism namely Phaenerochaete subglobosa and Schizophyllum commune and locally identidied Ganoderma applanatum. But some biotic and abiotic factors are responsible for the causes. The wood loss becomes a very high rate which shall impact the total loss of economy and the Sundarbans ecosystem. So, to overcome the disorder and disease special monitoring, care, multidisciplinary research and management system are to be required to formulate and eradicate the problem in the Sundarbans.