48 POTATO DEVELOPMENT WORK IN WISCONSIN. 



of potatoes, was brought over and scattered throughout the 

 United States before it was detected. It is carried over by plant- 

 ing infected tubers, and as it does not seem to be killed by disin- 

 fection, a certificate that a given lot of potatoes was free from sil- 

 ver-scurf would add materially to their value. 



8. Powdery-dry rot is a disease of stored potatoes that has 

 caused great losses from Wisconsin westward. It is carried over 

 in the soil where diseased potatoes are planted and the evidence 

 shows that whole new sections of Idaho have been thus infected, 

 and unnecessarily, but will now have to practice preventive mea- 

 sures, perhaps as long as potatoes are grown. 



9. The common late-blight dry-rot, carried south on seed pota- 

 toes, results in defective stands where the infected tubers fail to 

 grow, and not infrequently an outbreak of the blight itself is 

 charged to this use of infected seed. 



10. Curly-dwarf, a physiological trouble, and allied weak- 

 nesses, often classed as " running out," occur on some farms, 

 much more than others. Farmers have lost thousands of dollars 

 through buying unaware, such weak strains. 



11. Finally, leaf -roll, the new disease which has already cost 

 Colorado growers millions of dollars, is transmitted through seed 

 from diseased plants, and 1he best advice we can give is to get 

 healthy seed. To insure this, there has been successfully prac- 

 ticed in Germany a seed certification plan similar to the one we 

 are recommending. 



I have now given you a few examples to show why potato 

 growers in other sections need certified seed. If there were any 

 such seed in existence a demand for it could readily be aroused. 



Will not Wisconsin take the leadership and inaugurate the 

 plan to build up selected strains and maintain a high standard? 

 We can assure you that the U. S. Department of Agriculture will 

 heartily support the University at Madison and your association 

 in this important work, particularly in those phases which in- 

 volve trials in other states. 



