434 Brooks : The Fruit Spot of apples 



It would be difficult to decide from the earlier descriptions 

 given in the bulletins of the New Hampshire station (17) whether 

 the Fruit Spot or the Fruit Pit was under special observation. 

 The descriptions are better if taken as applying to the two diseases 

 than if considered as applying to either to the exclusion of the 

 other. The spraying experiments (17) were undoubtedly made 

 upon the Fruit Spot. So far as the writer has been able to learn, 

 a distinction between these two diseases has never been made. 



An associated fungus. — As a result of spraying experiments 

 made in the summer of 1906 the writer obtained data that agreed 

 with those of Lamson (17) as to the value of fungicides in pre- 

 venting the spotting of apples. Such results could be explained 

 only by assuming that the disease was of fungous origin or that 

 Bordeaux had some remarkable and undescribed effect upon the 

 skin of the apple. The former supposition seemed far the more 

 probable. As an initial test of the hypothesis, blocks of browned 

 tissue were removed from beneath the epidermis of the apple and 

 placed in sterile culture media. Agar and gelatin cultures in 

 which the nutrient substance was furnished by a decoction of beets, 

 beans, beef, or apples were tried with little but negative results. 

 The growths upon the different bouillons were too varied to give 

 any indication of a common fungus. It was noticed, however, 

 that after sections of spots had been left in water for a few days 

 they were overgrown by a fungus and matted together. The 

 fungus was always the same and always started from the center 

 of the spots. As a result of these observations liquid media were 

 given a more thorough trial. Browned tissue was transferred to 

 sterile distilled water and in four or five days the blocks were 

 fastened to the bottom of the test-tube or Petri dish. In fourteen 

 days a fungous mass six to ten millimeters in diameter had de- 

 veloped. Similar results were obtained with various bouillons, an 

 while the growth was quite unlike in the different media, trans- 

 fers from one to another proved that the fungus was the same in 

 all. It was also found that the fungus had not been obtained m 

 the agar and gelatin cultures because their surfaces dried too 

 quickly to give it time to develop. Placing the cultures in mo* 

 chambers remedied this trouble, but the development was slower 

 than that in liquid cultures. 



