210 BOAUD OF AGRICULTURE. 



Institute at Waterville. 



A second Institute was held at Waterville Town Hall, January 

 30, 1883, in connection with the winter meeting of the State Pomo- 

 logical Society', at which was given the following lecture : 



NATURAL HISTORY OF THE POTATO-ROT FUXGUS. 



{Peronospora infestans, Mont.) 



By C. H. Fernald, Professor of Natural History at the State College. 



The potato-rot has probabl}' been the cause of greater destruction 

 to the potato crops of the world than all other agencies combined. 

 Even the injury caused by the Colorado potato beetle is but slight, 

 when compared with that caused b}' the rot In j-ears past. 



The potato itself is a native of South America, found wild in 

 abundance in the mountainous regions of Chili and Peru, and the 

 rot occurred there even before its appearance in other parts of the 

 world ; in fact. South America, the home of the potato, is also, 

 without doubt, the home and center from which has been distribu- 

 ted the minute fungus which has caused such destruction to the 

 potato crops in all quarters of the globe wherever it has been culti- 

 vated. 



The disease first made its appearance with certainty in Belgium 

 in 1842, and in Canada in 1844, and also on the island of St. 

 Helena in the same year. In 1845 it spread with alarming rapidity 

 through Europe and the United States, at least the northern parts. 

 During the following four or five years it was distributed over the 

 world, wherever potatoes were cultivated, causing most distressing 

 results among those people who depended largely upon their potato 

 crops for support. During these years the destruction of the potato 

 crop b}' the rot, caused in Ireland one of the most dreadful famines 

 known in the annals of histor}', and it has been estimated that more 

 than a million persons died from starvation in that country-. 



Supposed Cause. 



Many theories were advanced to account for and explain the re- 

 markable phenomenon, as it was regarded. Some claimed that the 

 cause of the rot was a peculiar fungus, but what its nature was they 

 did not seem to have the slightest conception. Others su[)posed it 

 to be caused by insects, but by what kind and in what manner, it 



