March 1907.1 



Plant (Sanitation, 



Another experiment consisted inlaying straw down the rows, surrounding 

 each pruned bnsh, and a train of straw connecting bush with bush. The straw Avas 

 fired at the lower end of each line and ran up the row, slightly scorching each bush. 

 This proved to be quite as effective as the torches, but can be employed economically 

 only on sloping fields and in the neighbourhood of patna or grass-land. The cost 

 of straw or of the lengthy transport of grass would be prohibitive, or would— at any 

 rate— be more costly than the fibre and oil torches. Dried prunings might also be 

 employed in the same manner as straw or grass. This sorching system would be 

 found particularly useful on places where only a single field is attacked and — in con- 

 junction with the destruction of the prunings— should be effective in the extermin- 

 ation of the pest on such limited areas. 



The idea that dense shade is inimical to the borer was also investigated on 

 this estate and was partly confirmed and partly negatived. Tea that was growing 

 under a fairly thick shade of Dadap trees ( Erythrina) was found to be remarkably 

 free from the pest. Tea under Grevillea shade was less exempt, and some bushes 

 growing under dense shade of Cacao (but without other shade trees), was as badly 

 affected by the borer as any of the more open fields. These facts suggest that 

 exemption may be dependent upon the nature of the shade. It is well-known that 

 tea grown under Dadaps produces a much freer and more sappy growth, while 

 the bushes grown under Cacao alone were stunted and hard of wood. 



