302 MISSOURI STATE HORTICULTURAL SOCIETY. 



ture. Peiliaps the moniiiig glories protected the potatoes from mois- 

 ture of light rains and dews. 



Mr. Durlces. — Potatoes on northern slopes rotted but little. 

 Mr. Tracy. — The rot propagates by means of spores which will 

 germinate in a few liours. A lialf day will give you the second gener- 

 ation. None of them can germinate without moisture. So long as 

 they are kept dry they are entirely harmless. The more vigorous the 

 potato the less liable they aie to the rot. The spores germinate uiore 

 rapidly upon heated or weakened potatoes. Heated potatoes near the 

 surface of the i)round are wet by a heavy dew and are liable to rot. 

 Tlie rot attacks the potato by the eye, and rarely penetrates deeper 

 than the skin. When tliat is destroyed the potato decays from other 

 causes. Where potatoes are rotting badly the stem sometimes appears 

 velvety as if covered with a light frost. Vigorous growth in the plant 

 is one of the best preventives. There is no adequate remedy. 



Mr. iSpeer.—ls it safe for us to i)lant apparently sound potatoes 

 from last year's crop which rotted badly ? 



Prof. Tracy. — I think it will make but little difference. The spores 

 are all over the country and are ready to grow when the conditions are 

 favorable. Vigorous growth will do more than any otlier one thing to 

 prevent disease. A cool climate is also favorable. The spores will 

 germinate on the tuber or on the stem and then run down to the tuber. 

 When it germinates in the cellar the spores must liave been upon the 

 tuber before it was taken into the cellar. 



l*rof. Oshorn. — This season I have had experience it two States, 

 Missouri and Kansas, with potatoes. In Missouri they were worthless 

 from the rot. I think it owing to the fact that the vitality was sapped 

 by the excessive heat. In Kansas we had the drouth also, but I had 

 a large crop of prairie hay with which we mulched the potatoes live or 

 six inches deep. We had a fine crop, the mulch saving the moisture 

 and protecting them from the great heat. Some of us are old enough 

 to remember the potato famine in Ireland, when the crop from year to 

 year was a total failure. I think the cause was the degenerate condi- 

 tion of the potato. We obviate the difficulty by going back to seed 

 and getting new varieties, with new vigor, able to resist the disease. 

 This teaches us the lesson that no one variety of potato will last for 

 any great length of time; so it is necessary for us to keep growing 

 new. 



Mr. Ragan. — A great potato grower, who 'raised 40,000 or 50,000 

 bushels said the Early Rose rotted worse than anything else, while 



