346 



(STATE BOARD OF AGRICULTURE 



gave an average increased yield of approximately 42 bushels per acre over 

 seed with which it was compared. 



The inspection and certification of seed potatoes in Michigan is conducted 

 by the Michigan Potato Producers' Association in co-operation with the 

 Michigan Agricultural College. Information concerning sources of the cer- 

 tified seed and detailed information on the inspection and certification work 

 may be secured by writing to the Secretary of the Michigan Potato Producers' 

 Association, East Lansing, Michigan. 



Fig. 10. Harvesting a field of Certified seed potatoes in ScTioolcraft County. 



SEED TREATMENT 



Control of Scab and Black Scurf {Rliizoctonia) 



Seed potatoes should be carefully graded, and all ill-shaped, mechanically 

 injured, and partially rotted tubers should be removed before the seed is put 

 in the disinfecting solution. Potatoes should be comparatively free from 

 dirt before they are treated. 



Potatoes should be treated while they are dormant and before they are cut. 



Soak the potatoes for 30 minutes in a solution of corrosive sublimate 

 (bichloride of mercury), the strength of which is 4 ounces of corrosive subli- 

 mate to 30 gallons of water. 



Dissolve the 4 ounces of corrosive sublimate crystals in 2 quarts or so of 

 hot water, and then add it to the 30 gallons of unheated water. 



Corrosive sublimate corrodes metals. It should be used in wooden ves- 

 sels. A 50-gallon wooden barrel is a satisfactory container in which to soak 

 the potatoes. By using two or more barrels, a large quantity of potatoes can 

 be treated in a day. 



Where 100 bushels or more of potatoes are to be treated, the work can be 

 done more conveniently if a wooden trough or tank that will hold 8 or 12 

 potato crates is used. The potatoes in bushel crates are immersed in the 



