APPLE DISEASES 



465 



project from the tumor itself. The in- 

 terior of the tumor is white. 



It is not linown what other leguminous 

 crops are susceptible to crown gall. It 

 is believed, however, that there is reason 

 to suspect all of the clovers. 



(See Circular TIJ, Bureau of Plant In- 

 dustry.) 



*C}iiiidrosporioiini Fruit Spot 



CyUndrosporium pomi. Brooks 

 Occurrence and Symptoms 



The disease is of common occurrence 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 simk- 

 en. giving the fruit an unsightly api)ear- 

 ance which often greatly depreciates its 

 market value. The tissue beneath the 

 spots is dry and brown. 



The Funerus 



The first studies upon this disease seem- 

 ed to indicate that it was not produced 

 by a fungus, but recent studies have dem- 

 onstrated the causal relation of a fungus 

 which seems to be properly a species of 

 Cylindrosporium, as the title suggests. 



Infection probably takes place in July 

 or August when the stomata are being 

 torn open and the protecting layers of the 

 lenticles are not yet formed, a season 

 when the metabolism of the apple is ex- 

 tremely great and the transpiration 

 stream necessarily large. 



Control 



The disease is readily controlled by 

 spraying with Bordeaux, and weaker fun- 

 gicides are often very effective. Sprayings 



made as late as July have been found to 

 entirely prevent the disease. 



Charles Brooks 

 C()Li..\R Rot. See Sun Scald. 



f'oryneum or Orange Leaf Spot 



Coryneiim foUicolum 



Has a central, erumpent pustule with an 

 immediate border of orange yellow; this 

 yellow area shades off into dark color 

 toward the green tissue. Hartley has re- 

 ported, upon investigations of the fungus 

 in this case, that it is not actively 

 parasitic. Possibly we have this fungus 

 following something else, after the man- 

 ner that another fungus follows the black- 

 rot leaf spot. 



See R^ist of Apple. 



Die Back. See Rosette. 



A. D. Selbv. 

 Wooster. Oliio. 



• See Duggar, Fungus Diseases of riants, p. 

 341. 



Dropping of Apple Leaves 



Many leaves drop from apple trees in 

 summer and cause anxiety to fruit grow- 

 ers. Probably the three most important 

 reasons why the leaves drop are: First, 

 that the tree may regain a proper balance 

 between top and root. There is often a 

 great leaf development, owing to moist 

 conditions, and when drier weather comes, 

 there are too many leaves for the tree to 

 support, hence some of them drop off. 

 Second, that under certain conditions, 

 especially when there has been a wet sea- 

 son, leaves will scald and drop off. Spray- 

 ing sometimes causes this scalding. Third, 

 that the leaves are affected with a leaf 

 spot disease. The development of this 

 disease may, however, come after they 

 become weak from lack of moisture to 

 support them, or when the leaf is weak- 

 ened by sun scald. As a rule, under good 

 cultivation, there are quite sufficient 

 leaves left to develop the fruit properly. 



Dry Rot 



This is a disease which affects the 

 fruit and is indicated on the exterior of 

 the apple by small circular depressions. 

 When the skin is removed, dryish, brown 

 tissue is found at the diseased spots, and 

 when the fruit is badly affected, this 

 brown and pithy condition may be seen 

 extending through much of the fruit. The 



