SPRAYING 



229 



practiced on the late crop. It is well suited to wet seasons, as 

 much loose soil is thrown up to the row in which the tubers may 

 develop without growing into the deep soil when there is too 

 much water. Ridging is done by use of cultivators so adjusted 

 as to throw the soil toward the row a little at each cultivation. 

 Extreme ridging is not commonly practiced in most sections. 

 Where conditions are favorable level culture usually brings larger 

 yields. 



Irrigation is practiced with profit in the growing of potatoes. 

 The crop requires much water. In dry seasons potatoes suffer 

 for lack of enough soil moisture and the yield is greatly reduced. 

 Where irrigation is practiced, 

 even in humid climates, the 

 potato yield may be enor- 

 m o u si y increased. Two 

 methods are well suited to 

 this crop: (1) Furrows are 

 run between the rows and 

 the water from the head ditch 

 or head furrow is let into the 

 row furrows until the ground 

 is saturated. (2) The over- 

 head pipe system is used to 

 a considerable extent. 



Spraying. In all parts of 

 the country where potatoes 

 are grown commercially, 

 spraying is necessary to con- 

 trol the potato beetles. The 

 beetles feed upon the plants ging 

 and are readily killed by such poisons as Paris green, arsenate of 

 lead and arsenite of soda. Arsenite of zinc is also used. Paris 

 green is used in either the form of a spray or as a dust. In the 

 latter form it is diluted by being mixed with ashes or lime and the 

 mixture is dusted upon the plants when they are wet with dew. 

 A spray mixture is prepared by mixing from eight ounces to one 

 pound in fifty gallons of water. Strong solutions are usually 

 injurious to the plants. The addition of one-half pound or one 

 pound of lime to this mixture will help to hold the poison on the 

 plants, will help mark the area sprayed, and will help to prevent 

 injury to the plants by the arsenic. 



FIG. 103. Where potatoes are grown abund- 

 antly machines drawn by horses are used for dig- 



