NOTES ON THE ROTTING OP POTATOES. 5 



in the latter case the potatoes were subjected to the much severer 

 test of three months storag^e. 



CONCLUSIONS. 



From experiments on the keeping of potatoes and upon the 

 development of rot due to the late blight fungus, the following 

 conclusions appear warranted : 



The infection of the potatoes with the fungus occurs chiefly, 

 if not entirely, in the field before digging. 



The infection is usually the result of diseased vines. 



The disease is transmitted, in the majority of cases, not 

 directly through the vine, but indirectly through the soil. 



Potatoes may be infected directly in the field from spores 

 introduced in the manure, or from rotten potatoes spread upon 

 or left in the land the preceding year. 



Jones and Morse* conclude that the mycelium which produces 

 the rot normally passes into a dormant stage after infesting the 

 potato, but that abnormal conditions of moisture or temperature 

 may cause abnormal activity in the fungus, and hence the rotting 

 of the tubers. 



Whatever may be the explanation, these experiments all agree 

 in showing that, whether the vines have or have not been pro- 

 tected with Bordeaux mixture, there is far less liability of loss 

 from rotting in the cellar in the case of late dug potatoes. 



* Loc. cit. 



