i INTRODUCTION 9 



one most regularly used by the Chinese, in the Malay 

 Peninsula, for treating their vegetable and other 

 crops. 



The plant known as tuba (Derris elliptica) is a 

 woody climber propagated by cuttings. It will grow 

 in any corner of the garden and soon develops into a 

 fairly large mass of stems, lying on the ground. The 

 roots are pounded up in water and the decoction poured 

 or sprayed over the crop, where it will kill all cater- 

 pillars, grasshoppers, and other insects. It is perfectly 

 harmless to any plants. The decoction is poisonous to 

 human beings, but only when taken in large quantities, 

 and risk from it in the case of any of our spice plants 

 is infinitesimal. 



FUNGICIDES 



The best of all these is the preparation known as 

 Bordeaux mixture. This consists of a mixture of copper 

 sulphate and lime in water. The best formula is : 



Copper sulphate (bluestone) . . 4 Ib. 

 Quicklime (in lumps) . . 4 Ib. 



Water 50 gallons. 



No estate should be unprovided with a bag or two 

 of copper sulphate in case of an outbreak of any kind 

 of fungus. I have arrested many outbreaks of different 

 kinds of fungi on roots, stems, and leaves of plants by 

 the use of this excellent mixture. 



It is sometimes complained that under .certain 

 circumstances it burns the leaves of young plants. I 

 have never seen this occur. 



A very complete account of the making and use of 

 Bordeaux mixture was published by Mr. E. S. Salmon 

 in the Journal of the Board of Agriculture, vol. xvi. 

 No. 10. I reprint the following extracts from his 

 article : 



In purchasing copper sulphate, an article of 98 per cent 

 purity should be demanded; substance described as " agricultural 



