CALCIUM SPRAYS FOR THE CONTROL OF BITTER PIT 



Recent reports from other areas have indicated partial control of bitter pit 

 with the application of calcium sprays. 



For the past two seasons we ha-v^e conducted rather extensive trials with 

 calcium sprays for bitter pit control of Red Spy. 



In 1960, 5 pounds of calcium chloride in 100 gallons a^jplied as a foliage 

 spray about mid-June appeared to reduce the incidence of bitter pit. Two sprays 

 of calcium chloride applied in June and July did not reduce pit as much as the 

 single spray. This inconsistency along with the failure of the calcium sprays to 

 increase the calcium content of the foliage led us to question the apparent con- 

 trol of the single application of calcium chloride. Single and double applications 

 of 7.5 pounds of calcium nitrate per 100 gallons of spray were not effective in 

 reducing pit. 



In 1961, 4 sprays of calcium nitrate at 6, 4, and 2 pounds per 100 gallons 

 of spray and calcium chloride at 4, 2, and 1 pounds per 100 gallons were applied 

 August 31, September 9 and 22, and October 5. None of these treatments were 

 effective In reducing pit and one of the treatments had more pit than the control 

 trees. Chemical analysis of the fruit indicated that the calcium sprays had not 

 Increased the calcium content of the flesh or the peel over fruit from the control 

 trees. 



The failure of the calcium sprays to Increase the calcium content of the 

 fruit no doubt accounts for lack of control of the bitter pit. We have not given 

 up the possibility that calcium has a relationship to bitter pit development but 

 until we can show an increase in calcium content of the fruit from calcium sprays 

 and a significant decrease in the incidence of pit, we question the application 

 of calcium sprays as a practical method of control. 



Walter D. Weeks 



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