52 HATCH EXPEEIMENT STATION. [Jan. 



The Causes of the Failure of the Potato Crop of 



1897. 



The disastrous effect upon agricultural crops of the exces- 

 sive rainfall of the past season has been especially marked 

 upon the potato. The small yield and large amount of rot- 

 ting of this staple may be easily attributed to this source. 

 In all sections of the State, as well as beyond our borders, 

 the report has been general of a small potato crop and ex- 

 cessive rotting. This rotting has been generally regarded 

 as resulting from the well-known and ordinary "potato 

 rot" fungus, Phytophthora tnfestans. In fact, however, we 

 have to describe a series and variety of agents, which, 

 under the favorable influence of the excessive rainfall, — 

 an influence unfavorable to the vitality of the plant, — have 

 brought about the diminution and destruction of the crop. 



At planting time the ground was extremely wet. The 

 crop, however, started well, and the plants appeared above 

 ground in a promising manner. Continuous rains kept the 

 soil saturated with moisture, and before the plants had 

 reached a height of more than six inches it was noticed in 

 many places — usually the lowest and wettest portions of 

 the field — that many of them were dying. Such plants did 

 not collapse suddenly, but gradually turned yellow and faded 

 away, most of them dying eventually, though here and there 

 one would 1)e seen which maintained a feeble, stunted growth 

 through the season. This was the case not only in this 

 vicinity, but it was also reported from various parts of the 

 State. 



Investigation of affected plants showed that the trouble 

 was due to a rotting of the stem of the young plant below 

 ground, Avhich rotting evidently [)roceeded from the seed 

 potato, which was found in every case to be a putrid mass, 

 while the decay was gradually extending up the young stem. 

 Careful search for the cause of the rotting failed to reveal 

 any particular organism to which it could be ascribed. That 

 it was of bacterial origin seemed quite certain, as the de- 

 cayed tissue swarmed with organisms of this class, while no 

 fungus which could be considered the cause of the rotting 



