54 REPORT OF THE AGRICULTURAL RESEARCH INSTITUTE 



to a depth of about 3 feet and the outer corky tissues are 

 cut away with a knife it is found that the phloem has been 

 destroyed leaving nothing but the bast fibres; in the disin- 

 tegrated tissue between the strands of fibres white rhizom- 

 orphs occur and a fungus mycelium is everywhere common. 

 In dead and badly affected trees this condition is found 

 to extend up the trunk sometimes as much as 2 feet above 

 the soil. In such cases a fructification of a bracket fungus 

 (probably Fomes) is often found on the stem. In every case 

 examined in which this fructification was present the 

 phloem showed the diseased condition described above. 

 Thus while all unhealthy trees show a diseased condition 

 of the phloem, with the presence of a mycelium with rhiz- 

 omorphs, the most advanced cases of disease also bear a 

 sporophore. From field observations therefore there is a 

 strong presumption that the disease is due to the attack of 

 a basidiomycete of the genus Fomes; the fact that this 

 fungus is one of a group which is responsible for most 

 diseases of timber strengthens the evidence and moreover 

 the presence of rhizomorphs in the diseased phloem is what 

 would be expected in association with a Fomes fructifica- 

 tion on the exterior of the trunk. 



The fungus has been obtained in pure culture and will 

 be tested by inoculations. While it is not unlikely that the 

 fungus is the direct source of damage it will probably be 

 found that the conditions under which the sal trees are 

 living are such as favour the presence of a fungal parasite 

 and decrease the vitality of the sal tree. When the factors 

 which are necessary for the fungus to gain entrance into a 

 healthy sal tree are known it may be possible to control the 

 disease by altering the hygienic conditions under which the 

 trees live and thus lessening the chances of a successful 

 infection. It is improbable that it will be possible to apply 

 any remedial measures in dense jungle such as occurs in 

 Buxa; treatment might, however, be possible in the case of 

 plantations. 



(5) Rhizoctonia. Work on this fungus was continued 

 and the results are published as a memoir of the Depart- 



