I. THE FUNGUS THAT CAUSES BLACK-ROT OF GRAPES. 



BY DONALD REDDICK, 



While black-rot has been present in New York for a long time, 

 during the past few years losses from this source have been in- 

 creasing. In the period from 1 904 to 1906 they were very heavy, amount- 

 ing to an entire failure in many localities. Recognizing the serious 

 nature of the trouble and giving heed to the earnest request of certain 

 large growers, a thorough investigation of the nature of this disease has 

 been instituted at this Station. These pages are in the nature of a pre- 

 liminary report on the progress of the work. The facts here recorded 

 have been observed during the past year, at the special field station 

 located at Romulus, N. Y., and have been confirmed by observations in 

 other localities. No claim is made to originality for indeed most of the 

 observations recorded here have been published at some time 

 by various investigators in other State Experiment Stations, notably by 

 Scribner and later Galloway, U. S. Department of Agriculture; Chester 

 in Delaware; Price in Texas; Selby in Ohio; and others. 



It is a function of all plants to reproduce themselves and thus per- 

 petuate and propagate the species. This function is performed by the 

 plants with which we are best acquainted, by means of seeds. The seed 

 is a resting stage and serves to carry the plant through the winter. 



There are, however, a very large number of plants known to the 

 casual observer only by the effect they produce. This is because of their 

 small size and the necessity of a microscope to examine and study them. 

 They, however, are similar to other plants in that they produce a winter 

 or resting stage, the unit of which is called a spore. Among this large 

 number of microscopic plants is a group known as fungi. It is to this 

 group (many of them parasites), that we may attribute a large number 

 of the diseases of cultivated plants as well as some of those of 

 animals. 



Nature of black-rot. 



The black-rot of grapes is caused by a fungus which lives as a para- 

 site on the green parts of the vine and fruit, thus sapping the vitality of 



the vine and often destroying all the fruit. This fungus (Guignardia 



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