Jan. 21, 1918 Irrigation Experiments on Apple-Spot Diseases 119 



A study of the table shows that nearly all of the disease developed 

 during the first month of storage. The contrast between the plats, 

 however, makes it evident that the development of the disease was 

 largely determined by orchard conditions. The apples from the heavily 

 irrigated plats were in all cases more susceptible to bitter-pit than those 

 from the lightly irrigated ones. The amount of disease was much greater 

 on plats 4 and 6, which were irrigated heavily only late in the season, 

 than on plat i, which was heavily irrigated throughout the season. It 

 was less on plat 5, which had heavy irrigation followed by light, than it 

 was on plat 3, which received light irrigation throughout the season, or 



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Fig. 6. — Diagram showing the relation of the amount of bitter-pit to the size of apples. The bars show 

 the amount of disease on the different plats and are grouped according to size of apples. It will be noted 

 that heavy irrigation increased the disease as much on the small fruit as on the large. For the irrigation 

 of the different plats see figure 4. 



on plat 2, which received medium irrigation throughout the season. 

 The results indicate that the character of the irrigation during the last 

 weeks in which the apples are on the trees largely determines the amount 

 of bitter-pit developed in storage. 



The total amount of bitter-pit for the season is shown in graphic 

 manner in figure 5. All of the percentages are based on the original 

 number of apples. 



In the note taking of October 18 the apples were graded according to 

 size, and the record on bitter-pit made accordingly. The results are 

 given in Table V and figure 6. 



