JEHANGIR FARDUNJI DASTUR 231 



the tapping round trees affected with " Streepjeskanker." According to McRae 

 and Sundararaman^ in Mundakayam (Travancore) the rot of renewing bark 

 can be checked by putting with the thumb a thin smear of a mixture of tar and 

 tallow over the affected portion. When this paper was in the press the 

 author's Bulletin was reviewed in the Planters' Chronicle^ in which it is 

 stated that the " Black Thread " disease is exactly similar to " Bark Rot " 

 of Hevea in South India and that it has been found that a combination of 

 cessation of tapping on attacked trees with the application of a thin smear 

 of a mixture of tar and tallow to the diseased spot has proved very 

 effective. The mixture is applied with the finger and then rubbed with a 

 small piece of gunny so as to get only a smear confined to the bark area 

 attacked and its action appears to be two-fold. The tar acts as an anti- 

 septic while the tallow forms a waterproof covering and thus deprives the 

 fungus of the moisture so necessary for its growth and welfare. After the 

 monsoon the treated areas gradually shed a thin scale of tar coated bark 

 and expose a clean healthy surface beneath. Mr. Anstead, Deputy Director 

 of Agriculture, Planting Districts, Madras, has very kindly called my atten- 

 tion to the following extract from the Minutes of a Meeting of the Ceylon 

 Committee of Agriculture. " The Acting Government Mycologist has 

 instituted a series of experiments with a view^ to prevent further development 

 of the bark rot disease of Hevea rubber. All other trees under tapping 

 experiments have had the newly tapped surface covered with a thin coating 

 of a mixture made by boiling one ounce of sulphur in half a kerosine tin of 

 water and adding equal parts of fresh cowdung and clay till a thick paste 

 is obtained. A pinch of salt added will tend to keep the paste moist and 

 prevent cracking and peeling off the trees. The object is to protect the 

 exposed delicate cambium layer from sun and drying winds, as a precaution 

 against bark rot and to encourage good bark renew^al. This should be applied 

 monthly during dry weather within a quarter of an inch of the tapping 

 area." 



With regard to this last method it is difficult to see how^ this monthly 

 application within a quarter of an inch of the tapping cut will completely 

 prevent bark rot or " Black Thread " as the infection generally begins just 

 on the newly opened cut and very possibly the renewal of the bark on this 

 cut will have commenced before it gets covered with the mixture and then 

 the chances of its getting infected are considerably reduced. In South India 

 this mixture has also proved beneficial but it is applied all over the tapped 



' McRae, W. and Sandararaman> S. luc. cit. 



2 Anonymous. Bark Rot of Hevea, The Planters' Chronicle, XI, No. 31, 1916, p. 382, 



