DISEASES AND PESTS 45 



infected trees be burned, and that apparently healthy 

 trees in infected districts be treated with Bordeaux 

 mixture. A considerable force of men was employed in 

 the immediate restriction of the disease in this locality. 

 As a result of experience under the local conditions, 

 the use of fungicides was given up, and the work con- 

 centrated in the cremation of the sources of infection. 



A report of Mr. Macrae, Entomologist of the 

 Government of Madras, reports that in spite of all that 

 it has been possible to do to restrict this disease, it is 

 up to the present time continuing to advance at the 

 rate of a little over a mile a year. With minor excep- 

 tions the area affected remains continuous. The advance 

 has naturally been impeded for a time by such barriers 

 as river channels and palmless areas, but on the whole 

 has progressed in all directions at a remarkably even 

 rate. The campaign against it has resulted in a con- 

 siderable decrease in the mortality. The intensity of 

 the disease varies. Along water channels, on the side 

 of paddy lands, and on heavy or wet soil in general, 

 the mortality is greater and more rapid than in drier 

 situations. There is enough evidence now available to 

 show that the disease spreads : 



1st. Chiefly by palm climbers. 



2nd. To a smaller extent by insects (palm weevils 

 and rhinoceros beetles). 



3rd. Occasionally by the wind and by birds. 



The disease continues to attack the Palmyra palm 

 chiefly, the coco-nut being comparatively immune and 

 the Areca still more so. The coco-nut is rarely tapped 

 for toddy and the Areca never, and this is probably 

 the reason for their comparative immunity. There is 

 no doubt as to the share which is played by insects also 

 in carrying this disease. The rot has been found 

 especially prevalent near certain fishing villages, where 

 there were piles of decaying refuse, in which the coco- 

 nut beetles could multiply freely. Getting rid of coco- 

 nut beetles is one of the methods of restricting the 

 spread of the disease. 



