New York Agricultural Experiment Station. 2G0 



suckers tied up were heavily infected and yet few of them died in 

 less than three years. 



Spraying. — In regions where black rot is serious the first appli- 

 cation of spray for that disease, when the shoots are eight or ten 

 inches long, should prove very effective in preventing new infec- 

 tions on the shoots. Here, as in the case of black rot, it is absolutely 

 essential that the spray be applied before periods of prolonged rain. 

 The method employed in determining these periods in actual vine- 

 yard practice are detailed in a number of places, all of which are 

 available to the vineyardist who must spray for black rot. 



The black rot disease has rarely caused damage in the Chautauqua 

 belt and the writer knows of only one person who does any spraying 

 with the view of warding off this disease. Therefore, if any early 

 spraying is done it must be with the idea of controlling the infection 

 of the dead-arm fungus on the shoots. Since the majority of growers 

 cannot persuade themselves of the necessity of making the two 

 sprayings required to control the root worm, even though it has been 

 known since the work of Professor Slingerland (1906) that spraying 

 is effective, and in view of the fact that a relatively small number of 

 growers own spray machines it seems nearly useless to recommend 

 this method of control. Nevertheless there are a number of vine- 

 yards in which the early application of bordeaux mixture would prove 

 well worth while. 



The nurseryman who has a vineyard in connection with his estab- 

 lishment from which to obtain cuttings should make the early ap- 

 plications by all means. If he obtains cuttings from growers he 

 should insist that the vineyard be sprayed, unless a careful inspec- 

 tion reveals the fact that the canes are free from the disease. Such 

 vineyards are relatively scarce. Even though the cost of the cut- 

 tings were increased either on account of spraying or inspection, the 

 initial cost would be recompensed by reduced mortality. 



In certain years weather conditions are such that practically no 

 infection occurs. The year 1910 was of this character. Such 

 conditions cannot be forecast, however, so that the spraying cannot 

 be omitted. 



INFECTION EXPERIMENTS. 



In order to test the pathogenicity of this organism and to determine 

 in what manner the fungus might gain entrance to the tissues a num- 

 ber of inoculation experiments have been performed. 



