372 Diseases of Truck Crops 



ing, an ordinary knapsack or barrel sprayer (fig. ^l a) 

 will answer the purpose. For trucking on large 

 areas the use of power sprayers (fig. 71 b) becomes 

 necessary. It is difiSciolt to recommend the use of. 

 any one type when there are so many models on the 

 market. After consulting various catalogues and 

 examining types of spray machines at the county 

 fairs and other esdiibits, the grower will be in a posi- 

 tion to determine the kind of apparatus best adapted 

 for his conditions. A good power sprayer should be 

 capable of maintaining a pressure of at least one 

 htmdred pounds while the nozzles are open. The 

 sprayer should also have a convenient attachment for 

 spraying four rows or more, and should also possess 

 a device by which each row can be sprayed with 

 ' either single or double nozzles. Moreover, all the 

 working parts must be -easily accessible, simple, and 

 solidly built. 



Care of the Spraying Machine 



After each sprajring the outfit should be emptied 

 and carefully cleansed with water. Failure to do 

 this wiU restilt in the corroding of the tank, rods, and 

 nozzles. " 



Crop Rotation 



Many of the soil diseases, such as root knot, Fusar- 

 ium wilts, etc., may be economically controlled by 

 crop rotation. If a certain disease gains a foothold 

 in the soU, it is likely to become progressively serious. 



