33 6 Diseases of Truck Crops 



carried over with the seed. The importance of clean, 

 carefully selected seed cannot be too strongly em- 

 phasized. Selecting seed from resistant and highest 

 yielding hills is preferable to selecting from the bin. 

 In cutting the tuber into pieces for planting, none 

 should be used that show the least blemish or rot 

 on the outside, or decay or discoloration within. 

 By observing this precaution carefully, we shall 

 prevent our seed from carrying scab, rosette, and 

 many of the blights and wilts. Selected clean seed 

 alone will not give the desired result if it is planted 

 on infected soil. Less disease may be expected 

 when clean seed is planted on lands rotated with 

 alfalfa or grain, than when it is planted on virgin 

 land. 



Seed Disinfection. The object of disinfecting seed 

 is to destroy disease-producing organisms which may 

 be adhering to the exterior of the seed coat. After 

 the seed pieces are cut, they should be soaked for one 

 and a half hours in a solution made up of four ounces 

 of corrosive sublimate dissolved in thirty gallons of 

 water. It is desirable to disinfect the seed immedi- 

 ately before planting. Doing it a week to ten days 

 before planting leaves the risk of the seed undergo- 

 ing heat and having its germination injured. For 

 disinfecting large quantities of seed, the dipping 

 process is too tedious, and a preferable method is 

 that of the formaldehyde gas. This method re- 

 quires care, or else we are apt to injure the seed 

 badly. In this case, it is essential to have 167 

 bushels of potatoes for each one thousand cubic feet 



