180 MAINE STATE COLLEGE . 



Vermorel nozzle sold by Thos. Sommerville & Sons, Washington, 

 D. C, price $1.50 will be found the best, if recipe No. 3 is used. 

 The Nixon Nozzle, (Nixon Nozzle & Machine Co., Dayton, 

 Ohio,) or any other nozzle giving a fine spray will answer the 

 purpose, to apply the others. Make the application immediately 

 after a rain, or when fair weather is expected. Repeat if the mix- 

 ture is washed off by a hard rain. Apply about the time the 

 disease usually appears or anticipate it, or watch the field and 

 spray immediately on the slightest appearance of the disease. 



Preventive Methods. 



The following preventive measures are equally applicable, 

 whether the theory of winter spores is adopted or rejected. 

 The presence of the mycelium in decaying potatoes, or in the 

 stems, leaves and tubers left in the field, would make it advisable 

 to destroy all potato refuse. 



1. Burn the tops and leaves in the fall after the crop is 

 gathered. This is based upon the belief that winter spores are 

 developed in the stems and leaves, or that the mycelium may 

 possibly hybernate in them. 



2. Gather all the small potatoes. As the mycelium hybernates 

 in stored tubers, and possibly winter spores also occur in them, 

 they would no doubt survive in potatoes left on the ground. 



3. Select seed for planting, from fields or localities exempt 

 from the disease the previous season. Great care should be 

 exercised in selecting good seed. It is believed by some that 

 diseased tubers are the principal means of infection. 



4. Rotate the potato crop. This is based upon the belief that 

 the means of infection survives the winter in the potatoes, stems 

 and leaves left in the soil. 



5. Burn all decayed potatoes taken from the cellar, or bins and 

 all other potato refuse, do not throw them on the compost heap, as 

 the fungus retains its vitality and is spread far and wide with the 

 manure. 



6. Plant early in the season and those varieties that mature 

 early. This is based upon the belief that the fungus does not 

 mature until the warm summer months, and therefore early plant- 

 ings and early varieties would escape the disease from outside 

 infection. 



