MARKET DISEASES OF FRUITS AND VEGETABLES 7 



are really a soft fruit and much more susceptible to injury by 

 bruising than most varieties of apples. Most varieties of pears 

 need a special ripening temperature of 60° to 70° F., preferably 

 about 65°, after removal from storage. If Bosc, Flemish Beauty, 

 and Cornice pears are held in cold storage beyond their season, 

 they do not ripen satisfactorily when placed at 65° and may not 

 ripen at all. 



It should also be remembered that pears ripen poorly at 

 temperatures much above 70° F. The poor quality that Bartlett 

 pears sometimes have on the market may result from the fact 

 that they arrive at consuming centers in summer weather, when 

 the temperatures to which they are exposed in grocery stores and 

 markets and on fruit stands are too high for proper ripening. 



(See 83, 103.) 



QUINCES 



No recommendations are necessary for quinces beyond those 

 already made for pome fruits in general. 



Effect of Removing Spray Residue 



At various places in the publication, descriptions are given of 

 injuries that may result from washing apples or pears to remove 

 spray residues. It cannot be emphasized too often, however, that 

 if the washing is done with proper equipment and care and under 

 desirable sanitary conditions neither the market value nor the 

 keeping quality of the fruit will be impaired. 



Common Names of Diseases 



The common names of diseases used herein are for the most 

 part those that have become well established in publications on 

 plant diseases and that are in general use among persons con- 

 cerned with the growing and marketing of apples, pears, and 

 quinces. A few, such as Jonathan spot and York spot, include 

 the name of the variety on which they were first described or on 

 which they are most common. Some of the names such as bulPs- 

 eye rot, flyspeck, and scald are briefly descriptive of the diseases 

 to which they are applied. Still others contain the name of the 

 causal or inducing agent; among these are alternaria rot and 

 freezing injury. 



A few of the names imply a quality of the affected tissues which 

 is not really characteristic or typical, but they are so well estab- 

 lished by usage that it has seemed best to retain them. The 

 diseased flesh of apples affected with bitter rot and bitter pit is 

 not always bitter; black rot lesions are often only dark brown, 

 and brown rot lesions eventually become black. 



Most of the insect injuries are named for the insects that cause 

 them. 



APPLES 



Alternaria Rot 



{Alternaria tenuis auct.) 



CAUSE, OCCURRENCE, AND SYMPTOMS 



Alternaria rot of apple is caused by the fungus Alternaria 

 tenuis. In nature the organism grows on apple leaf tissue killed 

 by various agents as well as on other dead or dying plant ma- 



