960 THE COMPLETE GRAZIER. BOOK x. 



, The POTATO (Solanum tuberosum, L. ; nat. ord Solanacese). 

 Although, as a matter of convenience, included under the general term 

 of " root crops," it is necessary to remember that the potato of com- 

 merce is really an underground stem, that swollen modification of the 

 subterranean stem which botanists call a tuber. The " eyes " of the' 

 potato-tuber are leaf-buds, and, under suitable conditions, these begin 

 to grow in the same way as the buds on a slip, or cutting, from an apple 

 tree, or a geranium plant. 



The dreaded potato disease, which first appeared about 1845, with 

 most deplorable results in Ireland, is due to a fungus, Peronospora 

 infestans, or Phytophthora infestans, the spores of which are capable 

 of spreading from plant to plant with fatal rapidity, and of speedily 

 reducing a healthy crop to a repulsive state of putrefaction. In 

 dealing with this pest it is advisable to pay regard to the old adage, 

 " Prevention is better than cure," for it is well-nigh impossible to save 

 a crop that is once smitten. The attack is spread by the germination 

 of free spores upon the leaves of the potato plant, and it is to the 

 destruction of these spores that measures should be directed. For 

 this purpose the haulms should be sprayed with a mixture consisting 

 of 6 Ib. of quick lime and 6 Ib. of sulphate of copper (blue vitriol, or 

 bluestone) in 10 gallons of water. This is the bouillie bordelaise 

 (" Bordeaux stirabout ") of French cultivators ; it should be applied 

 (see fig. 292) before the crop shows signs of attack, and repeated in 

 close, humid weather which favours the development of the fungus. 



For the following valuable details on the cultivation of the potato 

 we are indebted to a grower of extensive practical experience, Mr. 

 George Maiden, formerly of Cardington, Bedford, though we have 

 modified references to varieties to bring them up to date. 



As in some years the production of potatoes is greatly in excess of 

 the demand for the table, and large portions have to be used as food for 

 live stock, no land should be planted with the crop that is not naturally 

 adapted for its growth. This would at once exclude all .-heavy soils 

 where the expenses are greater, and the yield and qualities worse than 

 on light land ; and, as potatoes are, or should be, a bulky crop, all land 

 where the expenses of transit to a station or local market are high. 

 Good drainage and cleanliness, particularly from willow weed and 

 thistles, are essential, as is also a sufficient depth of soil to form a free 

 tilth in which the rootlets can work and the tubers form. 



Heavy dressings of manure should be applied in the autumn or early 

 winter and ploughed in ; if not manured at that time, manure that has 

 been thrown up and heaped should be put on before planting in prefer- 

 ence to raw manure, which has a tendency to cause potatoes to grow 

 rank. The main object is to have the land in as light and loose a con- 

 dition at the time of planting as is possible. Though dung must be the 

 mainstay of the crop, top dressings of artificial manures are often 

 advisable, and the great favour in which superphosphate of lime is held 

 is shown by the large number of growers who use it to the extent of 

 from 3 cwt. to 6 cwt. per acre : it should be applied very early in the 



