0)1 the Prevention of Curl and Dry-Rot in Potatoes. 
163 
nearly transparent. Wherever the top was curled I found the 
stalks unsound and the set diseased. In some cases the disease 
carried the day, and the set reaching an advanced stage of decom- 
position, and the stalks below-ground becoming quite brown, the 
top died away. In a subsequent season (1844) most of the sets 
attacked perished ; but on this occasion a very great majority of 
the plants threw out strong roots, and finding an abundant supply 
of food, maintained a constant struggle with the disease, and 
eventually yielded a good half crop. A few green healthy plants 
stocxl prominently out amongst the brown half-withered tops of 
the rest ; and on examining these I found them to be plants of a 
white potato (known by the name of " Cheshire white"), a few 
chance sets of which had been accidentally mixed with the rest. 
These white potatoes had been previously in use for the table, 
but were very inferior, in point of mealiness, to the red ones se- 
lected for seed. The experience of this season convinced me that 
curl, dry-rot, and wet-rot, are one and the same complaint ; that 
curl is a mild attack of the disease, which, when violent, destroys 
the set before it can germinate; and thai it assumes the form of 
dry or wet rot according to the degree of moisture of the soil or 
season. I have repeatedly seen potatoes affected with dry-rot in 
a few days assume the appearances by which wet-rot is usually 
described ; and this change was evidently attributable to heavy 
rain which had fallen in the interval. The autumn of 1840 was 
remarkably fine ; and being anxious to take advantage of it I 
began to take up my potatoes as early as the 2nd of October, 
before they were ripe, and when, f jr the most part, they would 
not bear handling without what is provincially called " slipping 
their skins." 
1841. — As I still considered the red potatoes above-mentioned 
to be of good kinds, and that the occurrence of curl was acci- 
dental, I determined to give one of them another trial ; and 
accordingly, in 1841, 1 planted about an acre and a half with sets 
from the crop of 1840 which had suffered so much from curl. 
They were planted as late as the 8th of June, the land having 
been previously sown with lucerne, which had failed ; the weather 
dry and unfavourable ! yet, in spite of these disadvantages, they 
came up perfectly well, grew luxuriantly, and produced an excel- 
lent crop. Side by side with these potatoes two other kinds were 
grown : one a black kidney, a very superior potato for the table ; 
the other a cattle potato called the mangold wurzel. These were 
bought sets, nor do I know how they had been previously treated. 
Both, however, were failing crops. The experience of this season 
is valuable, running, as it does, directly counter to what has been 
so frequently asserted by the best authorities, viz., that curl is 
sure to increase, and that curled sets are to be avoided like the 
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