FUNGI IMPERFECTI 341 



48-60 x 2 fj.. They germinate readily, and evidently require but a 

 few days' incubation after infection for the production of the char- 

 acteristic shot-holes upon susceptible hosts. 



No ascogenous stage of this fungus is known, and there is some 

 doubt as to the ordinary method of wintering over. Stewart, how- 

 ever, has found the pustules of this fungus on the twigs of cherry, 

 and it is quite probable that this is one method of insuring its 

 transmission from season to season. 



Control. This, as well as other shot-hole-producing fungi, may 

 be controlled by the use of neutral or alkaline dilute Bordeaux mix- 

 ture, although the use of Bordeaux may be accompanied by in- 

 juries to the foliage. Weather conditions seem to affect greatly 

 its relations to foliage injuries, and this is particularly true with 

 respect to the peach and Japanese plums. In any case, however, 

 thorough spraying with strong Bordeaux should be given in the 

 early spring, whereas proper cultivation should be expected to de- 

 stroy leaves harboring the fungi from the previous year. 



XL. FRUIT SPOT OF APPLE * 



Cylindrospoiium Pomi Brooks 



Brooks, Charles. Fruit Spot of Apple, a Morphological and Physiological 

 Study. Built. Torrey Bot. Club 35 : 423-456. pis. 29-33. 1908. 



Occurrence and symptoms. This disease is of common occur- 

 rence in New England and is found in New York, Michigan, 

 Ontario, and probably in other sections of the United States and 

 Canada. The Baldwin is especially susceptible, but nearly every 

 New England variety is more or less affected. 



The disease appears about the middle of August as minute spots 

 or specks on the surface of the apple. At first these are indicated 

 merely by a deeper red color of the skin, if situated upon the 

 colored part of the fruit, or by a green color, if situated upon the 

 lighter portion. As the apple ripens the spots enlarge and many 

 of them become brown and sunken, giving the fruit an unsightly 



1 This account of the fruit spot was kindly prepared by Professor Charles 

 Brooks, New Hampshire College,- Durham, N.H. 



