OBSERVATIONS ON SOME VINE DISEASES IN SONOMA COUNTY. 



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The above consideration of the relations of the Red-leaf disease leads 

 one to conclude that the Red-leaf and the Rougeot are the more closely 

 related. If this conclusion is proved to be correct, then the grower 

 need not feel greatly alarmed even when a considerable percentage of 

 his vines are affected with the Red-leaf disease. 



RESULTS OF WINTER AND SUMMER SPRAYING EXPERIMENTS. 



Toward the end of January, 1904, the active help of three growers, 

 who were anxious to find a remedy for the Red-leaf disease, was 

 obtained. The vineyards of these growers are situated respectively in 

 the south, in the north, and in the east of Sonoma County. 



Those portions of their vineyards supposed to be most affected with 

 this disease were selected for experimental purposes. It had been our 

 intention to divide the plots off and to spray them after the manner 

 shown in the following diagram, but owing to inclement weather the 

 spraying with the iron sulfate was not completely carried out, except 

 at the East Sonoma experiment plot. 



1. Arrangement of Experiment Plots. 



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The TVor^/t Sonoma experiment plot was not sprayed with the iron 

 sulfate at all, and the diagram of the plot as sprayed would be: 



Bordeaux mixture 



Witness 



Bordeaux mixture 

 Witness 



Bordeaux mixture 



