76 Subtropical Vegetable-Gardening 



secticides is almost countless. Machines have been de- 

 vised for meeting the needs of almost any contingency. 



For dry materials. 



The simplest device to apply powders is a bag of coarse 

 woven fabric, in which the material is placed and then the 

 bag held over the plant to be treated. By shaking or 

 tapping the bag the powder sifts out and is more or less 

 equally distributed. Hand bellows to accomplish the same 

 purpose have been in use for a considerable time. Ma- 

 chines variously spoken of as powder guns and dust 

 sprayers are also on the market. Some of these are con- 

 structed so as to cover a very large area in a small time, 

 and under certain conditions become very efficient. 



Where it is practicable to use the dry material, it is 

 usually found more economical than the liquids, owing 

 to the weight of the water which is used in making the 

 liquid sprays. 



For liquids. 



The simplest forms for applying liquids are the hand 

 atomizers ; these work extremely well for small plants 

 and when a small area is to be covered, such as in seed- 

 beds, greenhouses and coldframes. 



The bucket sprayer and knapsack sprayer are quite in- 

 dispensable to the average general trucker, and in some 

 cases the knapsack sprayer only can be used for destroying 

 aphis on cucumbers and watermelons, as well as other gar- 

 den vegetables. When the work is to be done on a large 

 scale, the labor expense in using a knapsack sprayer be- 

 comes too great to make this form of machine profitable. 



