190 ARID AGRICULTURE. 



The white varieties (Pearl and Eural) 

 take the lead. It is important that a community 

 of farmers who are just becoming established, at 

 least, plant only one or two varieties in order 

 that they may supply a uniform product to the 

 market in sufficient quantities. 



Plate XXXIV. Potatoes on the YU. Ranch, Big 

 Horn County, Wyo. 



Photo by Stimson. 



THE The root rot (See chapter 18, Plant Dis- 



TREATMENT eases) and blight are very common potato dis- 

 eases and the first of these,, at least, can be meas- 

 urably controlled by properly handling and 

 treating the seed before planting, by change of 

 seed and by rotation of crops. Seed potatoes 

 may be kept from sprouting in the spring by fre- 

 quently changing their position in the root cellar. 



