Plat 



No. 



The Black Rot of the Grape and Its Control. 409 



Result of Black Rot Experiments in 1908. 



Treatment 



Bordeaux 4-4-^0, 6 appli 



cations 



Bordeaux 5-5-50, 4 appli 



cations _ 



Bordeaux 5-5-50, 6 appli 



cations 



Sprayed according to 



weather conditions 

 Cvdtivated but not 



sprayed 



Neither cultivated nor 



sprayed 



Seven check rows 



(i acre) 



Rotten 

 Per cent 



I . I 

 1-3 

 1 -4 

 o . 9 

 15s 

 17.1 

 9 5 



These figures show the efficiency of spraying from a commercial 

 standpoint. They give the total weight harvested, and the total weight 

 of the first grade as compared with the wine and the rotten berries. From 

 a scientific standpoint, however, they do not show the real value of 

 the spray because a rotten berry will weigh only about one-fourth as 

 much as a perfect berry. The only scientific method of determining 

 how effectively any spray protects the grape from the Rot is to count 

 the perfect and the rotten berries of every cluster. To do this on a large 

 area would be impossible. An attempt was made in the packing house 

 to secure these comparisons. From the grapes picked on the different 

 plats eight crates were taken. The perfect clusters were separated 

 from those containing rotten berries and these clusters counted and 

 weighed. The first four columns in the table on page 406 give 

 these data. Column 5 shows the per cent of imperfect clusters which 

 had only one rotten berry and the last column gives the average num- 

 ber of rotten berries on the imperfect clusters. This number of course 

 would be much smaller if all clusters were included. 



It must be remembered, however, that these figures do not represent 

 absolute conditions since many of the berries rotting early in the season 

 have dropped from the clusters. 



