68 Report of State Board of Horticulture. 



will spraying prevent all plant diseases? 



Several plant diseases, of which "peach yellows" is an example, 

 are not, so far as known, produced by organisms, and these diseases 

 can be neither prevented nor controlled by fungicides. 



Other plant diseases are produced by bacteria that live in the 

 tissues of diseased plants. These minute organisms seldom appear 

 on the surface of the host-plant, and consequently would not usu- 

 ally be reached by spraying. Such a disease is the pear blight. It 

 is often the case that a disease attacks only the underground por- 

 tion of the plant. It is clear that a disease of this nature could not 

 be prevented or controlled by spraying. Potato scab is an example 

 of diseases of this kind. In short, it is only those fungous diseases 

 that originate from spores on the above-ground portions of plants 

 that may be prevented by spraying. 



VV^ILL IT PAY to SPRAY? 



AA^hether it w^ill or will not pay to spray must depend upon cir- 

 cumstances. It is of prime importajice to know whether the plants 

 under consideration are subject to diseases that may be prevented 

 by spraying. If so, and the crop is worth raising at all, it is worth 

 bringing to the highest possible state of perfection, and it is now 

 well known that spraying, if properly done, is one of the important 

 factors in perfect crop production. However, unless one makes up 

 his mind to use all possible pains in the preparation of fungicides, 

 to begin spraying early, and to carry it on persistently, the time, 

 labor, and money expended will be lost. On the other hand, if the 

 fungicide is properly prepared, and the work is timely and thor- 

 ough, it is probable that no equal amount of labor and money ex- 

 pended will yield larger returns, taking it year in and year out. 

 This statement has been demonstrated many times by farmers, 

 gardeners, and fruitgrowers in nearly every section of the State. 

 It is true that certain seasons ai-e unfavorable for the development 

 of fungi, but it rarely happens that they do not develop to some 

 extent; hence it will be an advantage to spray even during such 

 seasons. Experience has shown that it pays to spray systematically 

 and thoroughly, year after year, regardless of the season. 



