212 THE DISEASES OF FRUITS. 



in the pantry quickly spoil, while those kept at a low temper- 

 ature in the ice-box may be wholesome for a much longer 

 time. 



Fungi are divided into two groups as regards the nature of 

 the substances upon which they thrive. Thus there are a 

 great many sorts that live only upon dead organic matter, as 

 in the case of the mould upon bread and cake, while others 

 grow only upon substances that are alive. These are called 

 parasites, and to this group the fungi producing the diseases 

 of plants belong. 



With this short general introduction the subject in hand will 

 be entered upon, and it is hoped that with the aid of the pict- 

 ures the text will be clear to all those who seek these pages 

 for help in coping with one of the most serious of the groups 

 of enemies to cultivated plants. 



It is the purpose to consider each of the leading fruits, giv- 

 ing a brief description of the most prominent of its diseases, 

 and follow immediately with any suggested remedies. 



The Pomaceous Fruits. 



THE APPLE : Rust. One of the leading enemies in the apple 

 orchard is the Rust caused by a fungus with a long botanical 

 name, which it is well to give here that any interested reader 

 may thereby have a means of looking up this rust in other 

 places. The rust of the leaves, stems, and even fruits of the 

 apple, is due to Gymnosporangium macropus Lk. It is not our 

 purpose to enter into a discussion of the literal meaning of 

 these botanical names. It is usually from some microscopic 

 characteristic ; but however that may be, the botanical name 

 of a fungus, like that of any other plant, is the same in all 

 languages and lands, and removes the doubt and confusion 

 that constantly arise when only the local name is used. In 

 further justification for giving the botanical name of each 

 fungus herein considered (when the species is described, and 

 therefore known to science, it may be said that the apple rust 

 in question is fully treated under its botanical name in the re- 

 port of the chief of the Section of Vegetable Pathology for 

 1888, with a colored plate, showing its forms and structure. 



The apple rust appears upon the foliage in oval patches con- 



