8 



to this, only three or four varieties, which apparently had little to recom- 

 mend them — beyond the fact that they were Cape seedlings — ^were 

 cultivated, and these were mostly propagated by runners. To-day I, think 

 we might estimate roughly that the value of apples grown in South Africa 

 would be about £30,000. Owing to the depredations of the woolly aphis 

 or American bhght (Schizoneura Icmigera), it soon became imperative that 

 all the introduced varieties should be on blight-proof stocks, and for this 

 purpose stocks of Northern Spy, Winter Majetin, and French Crab have 

 been almost exclusively used up to the present day. The Northern Spy 

 stock is preferred by some on account of its vigorous and erect growth, 

 with its compact, fibrous root, whereas others use the Winter Majetin, as 

 it makes a horizontal spread of branches and possesses long straggling 

 roots. Both these varieties are found to transmit their vigorous habit of 

 growth to their scions, and when this is considered non-advantageous 

 the difficulty is most frequently met by producing a dwarfing effect by 

 grafting in a Paradise Doucin scion. Then upon this intermediate bearer 

 the desired variety is grafted or budded. 



In the Western Province of Cape Colony, where the rainy season 

 comes on in winter, most of the orchards are under irrigation, and I shall 

 here describe the conditions prevailing at perhaps the largest orchards in 

 this particular part of the country, where I had an opportunity of making 

 most of my field observations on this disease, and from which most of the 

 fruit was supphed for its investigation. 



The Hex Eiver valley is situated at about 1,300 feet above sea level. 

 It runs, roughly, east and west, with mountains on each side, ranging from 

 7,500 to 4,000 feet. The soil in the valley is chiefly of a sandy nature 

 and various analyses showed that the percentage of silica varied from 

 88 per cent, to 97 per cent. The native vegetation in the valley is of a 

 decidedly xerophytic character. No fog or rains occur in the valley after 

 October. The apple trees blossom in October, and the fruit is plucked 

 in February and March. During the daytime intense heat is often ex- 

 perienced, both from the direct rays of the sun and also from the radiation 

 from the hot sandy soil. Nearly every afternoon during the sununer months 

 a breeze springs up and blows up the valley from the south-west to east. 

 The nights are always cool. The apples which first show evidence of bitter- 

 pit are frequently those which are most exposed to sun and the prevalent 

 winds. During the growth and development of the fruit, these orchards 

 are usually irrigated every ten to fourteen days. Irrigation is carried on 

 right up to the time that the fruit is ripe. The trees are planted twenty 

 feet apart, and nxunber one hundred to the acre. 



In these orchards three common troubles are found in the fruit. They 

 are sun-scald, water-core, and bitter-pit. Sun-scald is simply the result 

 of the injurious action of the intense heat set up in the apple by the direct 

 rays of the sun. Water-core, which is extremely common, is undoubted 

 evidence of water exudation under pressure. The cell sap fills the cells 

 to overflowing, but instead of bursting them, quietly diffuses through their 

 membranes or walls and then accumulates in the intercellular spaces. 

 In the majority of cases it finds its way to the exterior by exuding through 

 the cuticle, where it appears in the form of drops of a sticky fluid on the 

 surface of the apple. 



