T 



CHAPTER VII. 



INSECTICIDES AND SPRAYING. 



HE essence of remedial measures is to attack the insect directly, to make 

 life unbearable to him, to do something to kill him or to drive him 

 away. Such methods are but little known in India ; the methods of 

 killing- insects on a larg-e scale, of poisoning acres of crops, of putting 

 machinery on to deal wholesale destruction, do not occur in Indian 

 agriculture. At most, simple methods aimed at frightening the insects 

 are adopted without any co-operation. With the cultivator's knowledge 

 of the medicinal value of plants, it is somewhat strange that plants are 

 not used as insecticides to a greater extent. The juice of some plants is 

 poisonous to insects, as is the infusion of the dried leaves and roots or the 

 smoke made by slowly burning the dried plant. But such plants are little 

 used ; the juice of Euphorbia neriifolia is used to smear toddy-palms in 

 Gujarat ; the leaves of iiim are believed to keep off insects ; the infusion 

 of Adhatoda vasica or of Calotropis is used in irrigation Avater, as are 

 such substances as castor cake and khurasani. Dekamali gum, asafcetida 

 and similar drugs enter into the composition of such mixtures as " Gondal 

 Fluid.''' These are examples of the use of plants, but they rest on no 

 basis but that of tradition and are not always effective. 



It is singular that the value of tobacco infusion does not appear to 

 be more widely known ; this is one of the few plants used as an insecticide 

 in Europe, with hellebore {Veratrum album) , pyrethrum {Fyrethrum 

 cinerariafolium) , quassia [Picrana excelsa). From the use of these 

 plants, European methods of checking insects have developed more in 

 the direction of mineral poisons, a branch of entomology never practised 

 in India. At the present time far more reliance is placed on mineral 

 poisons than on vegetable poisons, and even the Kentish hop-grower is 

 abandoning quassia for soft soap. This is true also of America, where 

 the use of purely mechanical methods of checking insects is also being 

 developed to a high pitch. It has yet to be shown how far "Western 

 methods are applicable in the East. To the Western mind it is far 

 simpler to poison the plant by spraying on lead arseniate than it is 

 laboriously to pick off the individual caterpillars. The Eastern mind has 

 not yet fully grasped the idea that insects could be or should be killed by 

 hand-picking, far less by such a method as poisoning the plant with 



