POTATO DISEASE. 107 



and author of a valued work on the diseases of agricultural plants, 

 has for many years employed the following mode of culture with 

 success : The potatoes at planting are covered lightly two or 

 three inches and without raising the ground over them. So soon 

 as the tops begin to appear above the surface, the soil is thrown over 

 them loosely and deeply as possible, by a shovel-plow or other suit- 

 able instrument. A light wooden harrow is now made to traverse 

 the ridges lengthwise, so as to break down clods and fill up cavi- 

 ties, but not to reduce the height of the ridges much. In a few 

 days the sprouts appear again with renewed vigor, and the culti- 

 vation is then continued as usual to the end of the season. It is 

 important that the sprouts should be covered before they get much 

 above ground, otherwise they turn yellow and suffer. It is stems 

 and not leaves that must be buried. This method is not practica- 

 ble on heavy tenacious soil, but may be employed on all lands that 

 are well adapted to potato culture. It is well known that hilling 

 the potato increases the crop, for the reason that the tubers are 

 produced on stalks which issue from that part of the stem which 

 is between the surface of the ground, and the true roots. The 

 longer the vertical subterranean stem is, then the more numerous 

 will be the tubers formed. 



The French gardener. Hardy, has proposed a method to destroy 

 the fungus, (which he supposed, but did not prove to cause the 

 disease,) that has been much advocated in the south of England. 

 The potatoes are planted as usual, and as soon as the blight ap- 

 pears, the tops are pressed over with a roller, and kept flat. His 

 idea was that by this treatment spores would be washed off the 

 plant by the rain, and rendered innocuous. It is found that while 

 potatoes thus treated are not entirely saved, they are generally 

 less, and sometimes far less damaged than when the rolling is 

 neglected. The obvious explanation is that the spores that are 

 carried by rains from the tops into the ground, mostly, or in a great 

 degree penetrate the soil between the rows, and thus come less into 

 contact with the tubers. 



Still more efficacious is the method of Hornsey, which consists 

 in laying off the potato tops half right and half left along the rows, 

 and throwing soil upon the ridge among the stems and roots. If 

 the potatoes are well hilled up and treated in this manner, in most 

 cases a great saving may be expected, according to the testimony 

 of English farmers who have employed it. 



