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ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



Hampshire. It is dark brown or black 

 in color and the affected tissue com- 

 paratively firm. It is thus readily dis- 

 tinguished from the soft rots. It may 

 start on any part of the fruit, but often 

 begins at the blossom and frequently 

 follows insect stings. The disease is 

 primarily a rot of ripe fruit, but it may 

 often be found as dark brown spots one- 

 eighth to one-half inch in diameter sev- 

 eral weeks before the apples are mature. 

 These spots may develop very slowly 

 until about picking time, but after that 

 spread rapidly, involving the whole 

 apple. As the rot develops, numerous 

 minute, black elevations may be seen on 

 the apple (Fig. 1). These are spore 

 producing bodies of the fungus and are 



known as pycnidia. The rot does con- 

 siderable damage in cellar storage, but 

 is especially common on the fruit left 

 on the trees or ground. This worthless 

 fruit becomes a source of infection the 

 following spring. 



Canker is a term applied to rough, 

 imsightly wounds that are known to be 

 due to the action of fungi. The most 

 common variety of this trouble is the 

 "black rot canker," also known as the 

 "New York apple tree canker."* Both 

 large and small limbs are attacked and 



* Paddock. Wendell. The New York Apple 

 Tree Cankei'. New York Agricultural Experi- 

 ment Station Bulletin 1G3. 



Paddock. Wendell. Ibid (Second Report). New 

 York Agricultural Experiment Station Bul- 

 letin 18.5. 



Fig. 1. Black Rot o£ Apple Due to Spharropsis malorum, Showing Black Rot on Fruit, 

 Black Rot Canker on Limb, Early Stage of Leaf Spot (upper figure) and Late Stage 

 of Leaf Spot (lower figure). 



— New Hampshire Experiment Station. 



