1922.] Increasing the Commercial Value of Apples. 



the grower to buy his materials beforehand, when they are 

 generally cheaper than if purchased at the last minute. 



Apple Scab. — By far the most serious of the skin blemishes 

 are those caused by the fungus disease apple scab, or black spot. 

 This trouble is much more virulent in some seasons than in 

 others, but it is always present to some extent, and annually 

 causes an enormous loss to the growers of this country. Far 

 too often the crop of varieties that are liable to scab, which in- 

 clude some of our best dessert kinds, contains many more than 10 

 per cent, of apples blemished by the disease, and in bad cases it 

 is difficult to find an apple that is quite clean. It is therefore of 

 the utmost importance to growers who wish to make the most 

 of their crop by improved packing that they should be able to 

 control scab. Unfortunately our present knowledge does not 

 enable us to prevent it altogether, but we can control it to an 

 extent that is quite worth while. 



Mycologists seem rather to have lost faith in the value of win- 

 ter spraying to prevent scab, but many growers find it distinctly 

 valuable. In the writer's opinion spraying in early March, when 

 the buds have just begun to move, with a simple solution of 

 copper sulphate, 10 lb. to 100 gallons of water, is an excellent 

 start in the year's campaign against scab, brown rot, and other 

 fungus diseases. The chemical must be 98 per cent, pure, and 

 should be in powder form to facilitate dissolving. Lime-sulphur 

 at winter strength is also useful, provided that it is not applied 

 until the outside leaves surrounding the bloom clusters are on 

 the point of opening out. Further delay is dangerous, but slight 

 scorching of the outside leaves apparently does no ultimate 

 harm. If used too early lime-sulphur is of little value against 

 scab, and in any case copper sulphate is to be preferred for the 

 purpose. The latter scorches foliage badly, and must not be 

 applied when the buds are at all advanced. 



In some seasons this delayed winter spraying may do all that 

 is necessary against scab, but it is never safe to rely upon it. 

 The orthodox summer spraying is done within a fortnight after 

 the fall of the bloom ; and it ought to be repeated about a month 

 later. Bordeaux mixture is the most effective wash to use at 

 this time, but it is so liable to russet the fruit and to scorch the 

 foliage of certain varieties, that it has been given up by many 

 growers in favour of lime-sulphur used at summer strength. 

 This is rather less effective against scab, and there is some 

 evidence that it causes a proportion of the Drop to drop before 

 reaching maturity; but it does not russet the fruit, and is harm- 



