CHAP. XI. | THE CONTROL OF INSECT PESTS OF CI 



113 



lor purposes of cleaning or repair, and the valves should 

 removable and so made that they wear down evenly. 



Barrel Sprayers are suitable for field-work on the level and for 

 special work such as is required for orchards or experimental crops. 

 They eost about one hundred rupees each. On large holdings and 

 experimental stations a Barrel Sprayer is very useful for coping 

 with outbreaks of crop-pests but for the ordinary small holdings a 

 smaller type of machine is generally sufficient. 



Forms of Barrel Sprayers (as also of Knapsack and Bucket 

 Sprayers) have been placed on the market in India in which oil and 

 water are contained in separate tanks. It is claimed that these 

 may be mixed and sprayed in definite proportions as a mechanical 

 mixture, but such machines have in practice been found unreliable 

 in practical work and their use is now generally abandoned. 



l'n,. .so. " Autospray " in parts. 

 On the left i> the pump barrel and in the foreground thi piston with 

 ment fitting into the clips seen on top of the tanl 



Pressure Sprayers oi various types have been introduced of late 



ml it seems probable th.it these will oust the old patterns. 

 especially of Knapsack Sprayers, from the markets of the future. In 



these sprayers the spray-liquid is placed in the tank and airis then 

 pumped in until a considerable pressure is obtained and this 

 compressed air is use. I for the expulsion of the spray-mat. rial 

 No pumping is required therefore whilst the spraj is being applied 

 s 



