PAPERS ON BOTANY 159 



fungus. However, it has been the writer's experience 

 in dealing with sooty blotch, that in a season of consider- 

 able rainfall during the late summer, especially in 

 orchards poorly pruned, the trouble was generally pres- 

 ent on the fruit of nearly all varieties. For example, in 

 one Illinois orchard in 1917, he found sooty blotch on the 

 fruit from practically every tree and secured material 

 from apples of twelve varieties, which are not specifi- 

 cally mentioned in the literature as those on which the 

 fungus appears. 



III. COXTEOL 



Sooty blotch, being superficial, comparatively slow 

 growing, and appearing rather late in the season, is com- 

 monly well controlled in orchards properly located as re- 

 gards air and water drainage, where correct methods of 

 orchard management are foUoAved. 



On the other hand, it is practically impossible to ex- 

 clude it from orchards, on sites poorly located (Howitt 

 1911). Fletcher (1912), Selby (1900), and Sheldon 

 (1905) recommend the selection of an elevated site, where 

 the trees will secure sufficient air and sunshine. In Illi- 

 nois, in 1916, 1917, and 1918, according to my ovm obser- 

 vations, the trouble was much more commonly found in 

 unpruned than in pruned orchards, and in vigorous 

 yomig trees than in older more open-headed ones. The 

 year 1917 was comparatively rainy during the latter part 

 of the gro'^'ing season. The conditions were reversed 

 during 1918. Orchards under observation at Farming- 

 dale and Clinton, Illinois, fairly well pruned to admit sun- 

 shine and air, and located on elevated sites, were not 

 sprayed for the control of fungi in 1918. Scab (Ven- 

 turia inaequalis). blotch (PliyUosticta solitaria), and 

 black rot {Physalospora Cydon'iae) were common. Not 

 an apple, however, was found with sooty blotch. In the 

 Farmingdale orchard, moreover, during the previous 

 year, which was one of moderate rainfall during the latter 

 part of the growing season, the trouble had been found 

 wide-spread and abundant. It thus appears that the 



