52 VEGETABLE GARDENING. 



Varieties. The best varieties of potatoes to 

 grow are those that produce heavy crops of sound 

 tubers, and are at the same time of good table 

 quality. The following may be selected as fulfilling 

 these requirements, with this reservation, that cer- 

 tain varieties behave differently on different kinds 

 of soil : 



Early Varieties. May Queen, Midlothian Early 

 or Duke of York, Ninetyfold, Harbinger, Sir John 

 Llewellyn, Sharpens Express. 



Second Early Varieties. British Queen, Edzell 

 Blue, Macpherson, Burnhouse Beauty, King George, 

 The Ally. 



Main Crop Varieties. King Edward, Great Scot, 

 Arran Chief, The Lochar, Majestic, Abundance. 



For varieties immune from warfc disease, see page 57. 



POTATO DISEASES. 



Potato Blight (Phytophthora infestans). This dis- 

 ease, caused by a parasitic fungus, is the one which 

 commits so much havoc among the potato crop in 

 wet seasons, and against which spraying with a 

 fungicide is usually adopted as a preventive. The 

 first signs of attack are the presence on the leaves of 

 brown spots, which gradually increase in size and 

 become darker in colour. In damp, sunless weather 

 these diseased patches rapidly extend, until in a 

 severe attack almost the whole of the foliage col- 

 lapses and blackens, giving off an offensive odour. 

 On examining the under-surface of an affected leaf 

 a fine white mould may be seen, which consists of 

 the spore-bearing or reproductive part of the fungus, 



