April, 1912.] SOME APPLE DISEASES — TREATMENT. 



15 



that these are in reality numerous bands of diseased tissue that 

 follow the irregular course of the food-conducting vessels. These 

 vessels are abundantly distributed in the portion of the apple 

 that is within 1-2 inch of the surface (Fig. 16). The brown streaks 

 are correspondingly^ abundant in this portion of the apple (Fig. 15). 

 The brown streaks may occur without the pitting on the surface. 

 This condition is particularly common on apples in cellar storage. 

 The disease is reported to be worst in warm, rainy seasons. 

 It is especially common on large apples and on the fruit from 

 trees that are in an unhealthy condition. It may occur, however, 

 on trees in almost every condition of age and vigor. It is not 

 due to fungi or bacteria. Nothing definite can be given as to 

 prevention. 



SOOTY BLOTCH AND FLY SPECK. 



Leptothyrium Pomi (Mont. & Fr.) Sacc. 



The Sooty Blotch and the Fh' Speck of the apple were for- 

 merly thought to be caused by two different fungi, but a recent 

 writer^ claims that one fungus 

 is responsible for the two dis- 

 eases. The names given these 

 two effects characterize their 

 appearance. The former pro- 

 duces blotches 1-8 to 1-2 

 inch in diameter on the fruit 

 (Fig. 17) and the latter 

 numerous minute specks. 

 They give the apple a sooty 

 appearance that depreciates 

 its market value. The fun- 

 gous growth is entirely on the 

 surface of the fruit, and 

 hence the disease is espe- 

 cially dependent upon moist 

 weather for development. 



Treatment. The disease is 

 readily controlled by spraying. Thoro pruning is important, and 

 if light and air have free access to the fruit the disease usually 

 gives little trouble. 



IB. F. Floyd in Duggar's Fungous Diseases of Plants, p. 367,1909. 



Fig. 17. — Sooty Blotch of apple 



