48 . FRUIT AND POTATO DISEASES 



unsightly. This disease is characterized by dirty or sooty'spots 

 on the skin of the apple. Tiie spots are roundish in outline; 

 varying much in size, they often run together, covering nearly 

 or quite the whole surface of the fruit. If drops of water con- 

 taining soot or lampblack were allowed to evaporate on the 

 surface of the apple, they would produce an appearance resem- 

 bling this disease. Its fungous nature, however, is clearly 

 revealed by the microscope. It is entirely superficial and, as 

 in case of the spot disease, the principal damage produced by 

 it is disfigurement. This disease is frequently observed on 

 Greenings and Northern Spies, but in 1S96 it attacked_many 

 other varieties, among them the Baldwin. 





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I'm. 2. — Apple affected with sooty disease. 



The sooty disease frequently attacks pears ; it is especially 

 bad on Beurre de Anjou and Lawrence. In case of the latter, 

 the favorable etiect of spraying with Bordeaux mixture has 

 been reported on in a previous Bulletin of this station (No. 27). 



In 1S96, although no exact count was made, it is safe to say 

 that the sprayed apples showed 75 per cent, less of the disease 

 than the unsprnyed. 



BLACK KNOT OF PLUM 



It is probable that plums might be raised with profit in many 

 parts of New Hampshire, if it were not for the disease known 

 as black knot. Until recently it has been thought that the only 



