640 POTATO ROT. 



Some frnit trees are affected with the canker, especially the 

 apple tree, Mr. Knight asserts, from his own experience and 

 observation within the last twenty years, that this disease 

 becomes progressively more fatal to each variety, as its age 

 increases beyond a certain period, and that all the varieties of 

 the apple which he has foimd in the catalogues of the middle 

 of the seventeenth century, are unproductive of fruit, and in a 

 state of debility and decay. Those are most exposed, which 

 had an excessively vigorous growth in their early years. 



The potato disease appears in three forms. The first, a 

 shrinking internally, leaving a hollow in the centre, called gan- 

 grene. Another, where the tuber becomes soft, pulpy and 

 moist, like a rotten apple. This is the moist gangrene. This 

 is the disease which has caused such loss to the farmer, such 

 detriment to the State, and deprived both man and beast of 

 much wholesome food, which was formerly a source of much 

 wealth. A third form is distinguished by a collection of black, 

 dry matter, in the body of the tuber. This prevailed to some 

 extent, a few years since, but whether a distinct disease, may 

 admit of doubt. 



Remedy. At an early stage of the disease, when its ravages 

 were more confined to old subjects, in a state of debility and 

 decay, Mr. B. thinks it might have been arrested by resorting 

 to seed, instead of raising from the tuber. Such a practice, 

 even now, he thinks might be of great benefit, and, if gener- 

 ally followed, would reduce the disease from an epidemic to a 

 sporadic character, and might possibly effect a cure. And this 

 is the remedy, which it was the writer's purpose to propose. 

 Two auxiliaries are suggested by him. 



Planting- the potato in the fall has been considered in 

 England and France a useful practice. It was adopted in 

 England at the begiiming of the present century, when the 

 disease called the curl was very prevalent. It has been lately 

 recommended in France, as a cure for the present disease. 



The application of salt is the other auxiliary. This has 

 been used with effect as a preventive and cure of the mildew ; 

 and if the disease in the potato is in part owing to fungus, it is 

 reasonable to suppose it may be fatal to this also. The mode 



