Dalbergia sissoo die back-probable suspects
Dalbergia sissoo die back-probable suspects
Muhamamd Arif Chaudhary and Ejaz Ahmed
ABSTRACT
The number of dry patches, beneath the bark in the sapwood were maximum (5) in thinned canopy followed by top die (3) and vertically half dead (1). The continuity of such patches towards crown and root was confirmed by making the cross sections of stem logs and excavating root system of top die tree. Besides, there were recorded 9 dead roots in top die, 7 in thinned canopy, 6 in vertically half dead and none in healthy. A maximum number of termite royal chambers with fungal garden were noted in thinned canopy followed by completely dead, top die and healthy tree. White or black fungal material and decay of roots were recorded on all the tree roots except completely dead. However no Rahizobial nodules were noted on any of the tree root system. All cross sections depicted the presence of white powdery streak at center or at periphery of damaged central part. Small out growths directed from heart wood into sapwood were noted in first 3 cross sections of first 3 consecutive logs.
Presence of i) white or black fungal material both on stem and root ii) exudation either of black or red blood colour iii) dry patches in stem/root and drying of roots and iv) white powdery streak in cross sections are leading to the conclusion that there have been the possibility of some fungal attack resulting in blockage of conducting tissues, causing heart wood rot followed by termite attack and elimination of Rahizobial nodulation. Therefore, it is suggested to carry out an intensive field survey; study the biology, physiology and ecology of the suspected fungi and Rhizobial nodulation pattern.
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