64 HATCH EXPERIMENT STATION. [Jan. 



ease needs no description to those who have ever tried to 

 raise any of the above-mentioned fruits. It appears in the 

 summer, some time after the fruit has set, often just as it 

 comes to maturity, or even earlier in the season, the time 

 of its appearance depending a great deal upon the weather, 

 a warm, rainy period being liable to bring it on at any time. 

 Indeed, it does not always wait for the production of fruit 

 upon which to make its attacks, but often develops upon the 

 blossoms, causing them to abort, and spreading thence into 

 the young twigs upon which they are borne, results in their 

 death. Upon the fruit the rotting is almost always found 

 to some extent at the time of ripening, and, as already 

 mentioned, often occurs earlier in the season when the 

 weather is favorable, i. e., warm and moist. At such times 

 the greater part of the crop is sometimes destroyed. In 

 cherries the chief damage is done upon the ripe fruit. In 

 peaches and plums, which have a longer season of ripening, 

 the young fruit is more frequently affected. Early peaches 

 are considered more susceptible to the disease than the later 

 varieties. 



The cause of this disease is a mould-like fungus (a true 

 parasite, nevertheless), which spreads its vegetative fila- 

 ments through the affected fruit and thus causes its decay. 

 Wet weather brings about the rotting of the fruit by favor- 

 ing the growth of the fungus, not by its direct effect. Fruit 

 which is affected begins to discolor and soften, and gradu- 

 ally dries up and shrivels into a shrunken mass about the 

 stone. It often remains on the tree for months, especially 

 in the peach. In the early stages of infection the surface 

 becomes covered over with little grayish spots of a powdery, 

 dusty nature. These are clusters of the spores of the fun- 

 gus, produced in countless numbers on the ends of filaments 

 from the inside of the fruit which have pushed out through 

 the surface. These spores, which serve to reproduce the 

 fungus, are extremely minute in size, so that en masse they 

 appear as a fine dust. Being easily carried by the wind, 

 they are spread far and wide, and may thus infect a large 

 district in a few days, under favorable conditions. After 

 becoming dry and hard the affected fruits cease producing 



