Diseases of the Potatoe. 29 
the Potatoe Plague, which will be fully described in Part 
II, of this treatise : 
“The cause of the rust this season, (1839) we believe to 
be ihe extraordmary humidity, combined with a peculiar 
state of the atmosphere, at some period in the high heat of 
summer. It was remarked that the rust struck universally 
on the 27th of August. Early planted potatoes were not so 
much injured by itas the later crop. Last year, it will be 
remembered, the severe drought in that part of the country 
south of a line drawn east and west, at the distance of fifty 
to seventy miles north of Boston, generally lessened the crop 
of potatoes, affecting those early and late planted in a similar 
manner that the rust has this year injured them. It was too 
dry last summer, and the uncommon wetness of the present 
summer has been alike injurious. More than half the days 
in June, and two-thirds the days in July, and one third in 
August were rainy days. In a season so uncommonly wet 
we could not but anticipate quite as much injury to some 
crops as we have suffered. The benefits to the grass crop 
and small grains, have amply compensated for every thing.” 
In 1841, a correspondent of the Maine Farmer wrote as 
follows : 
“ Almost all persons with whom I have conversed on the 
subject ascribe the failure of the potatoe crop to rust; and I 
know very- well the tops have a rusty appearance, while some 
few have mentioned other causes. I have had ample time 
and opportunity to examine numerous fields under all the 
different circumstances of soil and culture, and time of plant- 
ing, which could be found, and the result in my mind was 
satisfactory that no single cause assigned could alone pro- 
duce it. In one field, planted partly with the pink-eyed 
variety, and partly with the long reds, the pink-eyes were so 
dead, the tops, on pulling, broke off, withont pulling up the 
potatoes, and the owner had commenced digging. The long 
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