14 KANSAS Academy of Science. 



THE BLACK ROT OF THE GRAPE. 



BY CHAS. R. CARPENTER, M. D. 



Of the diseases of the grape, probably none is more destructive than that which 

 is known as the Black Rot, where it occurs in a pronounced form. And in this State, 

 where it occurs in its most destructive form, it is important to viticulturists that 

 they understand the causes of the disease, the conditions under which those causes 

 become operative, and the intelligent method of treatment. 



After the investigations of Scribner, Trelease, Ellis, and others in this country, 

 and Viala and Ravaz in France, it would seem almost superfluous to discuss the 

 question whether the rot is a parasitic or a trophic disease. Nevertheless it is being 

 discussed, and good arguments being adduced on both sides; both good, for the rea- 

 son that both are correct. 



No profound result is accomplished in nature by the action of a single isolated 

 cause; and it is no more to be expected here than elsewhere. To argue that the 

 jjhoma uvicola, or as its mature form is now called, the x>hysalospora Bidivellii, does 

 not operate as a cause in this disease, is to invite the suspicion of a limited knowl- 

 edge of the character and natural history of this fungus. To argue that the trophic 

 condition of the vine does not operate also as a cause, is to argue that a man who 

 is starved, whose blood is vitiated from the absence of proper food, whose tissues 

 are imperfectly sustained, and whose entire functional organism is impaired, is not 

 more susceptible to the advent of disease than a man who is strong, well-nourished 

 and healthy at the time of exposure. The hard and fast rules of common sense are 

 to be applied to the physiology and pathology of vegetable organisms in the same 

 manner as they are applied to the physiology and pathology of animal organisms. 



To one accustomed to study the causes of things it seems almost inevitable that 

 an imperfect nutrition of the individual, whether animal or vegetable, and a corre- 

 spondingly low condition of vitality, should invite disease. Disease may be defined 

 in general terms as any interference with the natural process of waste and repair in 

 an organized body, and the mechanical results of that interference. If nutrition is 

 withheld entirely, dissolution is the result. If it is withheld partially, dissolution is 

 favored, because the conditions are furnished which are necessary for the operation 

 of those causes which produce an entire interruption of the process of waste and 

 repair. 



We may have an interference with the process of waste and repair which does 

 not affect the entire organism. It may affect a very small portion of the organism, 

 and hence we have hundreds of trivial diseases which produce no tendency to disso- 

 lution whatever in the general organism. The black rot is a grave disease, tending 

 to direct and immediate dissolution in that part of the organism affected, the fruit- 

 And hence any condition which favors dissolution favors the operation of any cause 

 that is capable of producing the disease. Deficient nutrition manifestly favors dis- 

 solution; it therefore operates as a predisposing cause of the black rot. But defi- 

 cient nutrition operates as a cause of disease in general, because it is a general 

 condition. It predisposes to any and all diseases, systemic as well as local. 



What then determines the advent in one case of the black rot, in another the 

 grape mildew, in another the powdery mildew, and so on through the whole list of 

 the grape diseases'? 



Some would argue that a deficiency in the supply of some particular element or 

 elements might give character to the different diseases, and that the three species of 

 fungus that occur so evidently in the three diseases mentioned are simply three ac- 

 cidental growths; that they do not act as a cause, but are simply a result. 



