78 THE COMPLETE GARDEN 



the plants in the form of a very fine powder which is largely dependent 

 upon atmospheric moisture to make it stick to the plant. Dust sprays 

 are used more often in a commercial way than by the average amateur 

 when protecting ornamental plants, and this form of spray is not 

 adapted to all the chemicals used, as, for instance, the oil and tobacco 

 extract sprays. Sometimes poisons are mixed with bait and spread 

 upon the ground near the plants to be protected, but this again is not 

 spraying in the generally accepted sense of the word. 



Outfits for Spraying. There are various spraying outfits adapted to 

 the various requirements dependent on the amount of work to be done 

 and the physical difficulties to be overcome. Probably the best small 

 outfit for the amateur is the knapsack sprayer which can be easily 

 transported and even carried up into the tops of trees if necessary. 

 This consists of an airtight receptacle for the spray mixture, which 

 may be strapped to the back in such a way as to easily allow the 

 pressure to be kept up with one hand while the nozzle attached to a 

 short length of hose is manipulated in the other hand. The best 

 knapsack sprayers have a copper tank holding about four gallons of 

 liquid, a brass pump, and an air pressure chamber which insures a 

 steady stream. They weigh fifty pounds when full of liquid. A 

 cheaper pump of about the same type but small capacity is the bucket 

 pump which can be used with any bucket or pail. This is harder to 

 transport about and not so satisfactory in other ways as a knapsack 

 sprayer. There are various types of hand-operated barrel outfits. 

 Sometimes the barrel is mounted on large wheels so that it can be 

 easily moved about with a pump installed in the head of the barrel, or 

 sometimes a larger hand-operated pump is mounted on a cart beside a 

 barrel or tank. Such an outfit will take care of all but the tallest 

 trees and is about the largest suitable for amateur spraying. It has 

 enough capacity to take care of considerable spraying and enough 

 pressure to insure a fine spray reaching all parts of even large plants. 

 For occasionally spraying small shrubs and such plants as perennials 

 and annual flowering herbs a small hand force pump is a very con- 

 venient one to have. These small pumps hold a quart of liquid in a 

 glass or copper retainer. 



The power sprayers are operated either by a gearing or sprocket 

 and chain connecting the wheels of the outfit to the pump or by a 

 gasoHne engine mounted on a platform together with a pump and 



