38 BOARD OF AGRICULTURE. 



tion of it for so long, that I think I can tell with certainty, 

 if we have certain conditions of weather in summer, when 

 the potato-crop has reached a certain stage of growth, that 

 the potato-rot will take place forthwith. It requires, as I 

 have observed, a mild, warm state of the weather, after a 

 shower, — such weather as we farmers call " scalding weath- 

 er." Probably every one here understands that. When 

 the potatoes are in blossom, or have just gone by the stage 

 of blossoming, and are growing very vigorously, if we have 

 a spell of moist weather, or if, after a shower, the weather is 

 warm and close, very little air stirring, the conditions are 

 favorable for the potato-rot or fungus to take hold of the 

 plant. I believe that the air is filled with the spores, or seed, 

 of this and other varieties of fungus most of the time ; and 

 when the conditions are right for the propagation of those 

 seeds, then they take hold and grow. That, to my mind, is 

 the cause of the potato-rot. Sometimes it affects the early 

 crop. When the early crop is in a condition such as I have 

 stated, and the weather is such as I have described, the early 

 crop will be affected by the potato-rot; but, if we do not 

 happen to have such kind of weather at the peculiar stage of 

 growth of the potato, we do not have the potato-rot at the 

 early season ; but it may come later, and affect the later 

 growth of potatoes, depending upon the condition of the 

 growth of the potato-vines and this peculiar kind of weather. 

 We have another fungus that troubles our farmers very 

 much who are in the habit of raising onions. It is called, 

 among farmers "smut." This operates quite differently 

 from the potato-fungus, that affects the potato, and causes it 

 to rot. The spores of the onion-smut will infect the whole 

 soil of the onion-field. It is very rapid in its propagation ; 

 and we find sometimes the land infected with what we call 

 the " onion-smut." There is no remedy for it that I know of, 

 except to refrain from raising onions on that land for three 

 or four years, for this fungus will remain in the ground cer- 

 tainly two years, and very likely three ; and it is carried 

 from field to field by the implements that may be used. The 

 ploughs, harrows, rollers, and drags that are used on the onion- 

 field are impregnated with the spores of the onion-smut, and 

 it is transmitted from field to field in that way. It is wonderful 

 how long the spores, or seed, will retain their virtue, — three 



