Dec, 1909.] 



SOME APPLE DISEASES. 



121 



shows 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 14 inch of the surface (Fig. 16). The 

 brown streaks are likewise abundant in this portion of the apple 

 (Fig. 15). 



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

 has often been found on limbs and trees that have been weakened 

 by canker or by overbearing. Nothing definite can be given as 

 to prevention. 



SOOTY BLOTCH AND FLY SPECK. 



Leptothyrium Pomi (Mont. & Fr.) Sacc. 



The Sooty Blotch and the Fly Speck of the apple were for- 

 merly thought to be caused 

 by two different fungi, but 

 the recent work of Floyd^ 

 indicates that both are due 

 to the fungus indicated 

 above. The names given 

 these two effects character- 

 ize their appearance. The 

 former produces blotches 

 Ys 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 de- 

 preciates its market value. 

 The fungous growth is en- 

 tirely on the surface of the 

 fruit, and hence the disease 

 is especially 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. 



Fig. 17.—" Sooty Blotch " of apple. 



> B. F. Floyd in Duggar's Fungous Disea.ses of Plants, p. 367 



