186 THE POTATO 



ture agitated should be used. If no mechanical 

 contrivance is available, stirring should take place 

 frequently while the work is in progress. 



"The amount to be applied per acre varies with 

 the quantity of haulm in the crop to be treated, but 

 is usually from 100 to 150 gallons where the foU- 

 age is fully developed. The plants must be 

 sprayed from underneath as well as from above, 

 so as to reach the fungus on the under side of the 

 leaves. Machines can be obtained which spray 

 the plants from below. 



"The cost of a single spraying need not exceed 

 $2 per acre, and, with certain horse machines, 

 thirty acres can easily be treated in a day. Bor- 

 deaux mixture does not begin to work until several 

 days after it has been applied, and it must, there- 

 fore, be used some time before any symptoms of 

 disease are to be expected, say, toward the end of 

 June, or early in July, according to the locality and 

 season. The crop should be sprayed twice at 

 least. The first spraying should take place as 

 soon as there is a good development of haulm, the 

 treatment being repeated about three weeks later 

 when the growth is complete. If only one spray 

 ing is given it should take place about the middle 

 of July." 



POTATO SCAB 



Oospora scabies is one of the most common 

 potato diseases. 



In "Bulletin 71" of the Wyoming Experiment 

 Station it is described as follows: 



"This fungous disease is too well known to need 

 any description. All who use as well as all who 

 grow potatoes know the familiar, irregular, sore- 



