SUGGESTIONS FOR USE OF CALCIUM SPRAYS IN 1982 



Mack Drake and William J, Bramlage 

 Department o£ Plant and Soil Sciences 



Calcium chloride (CaCl2) foliar sprays are recommended in 

 Massachusetts for all apple growers to increase the flesh cal- 

 cium (Ca) content. Higher flesh Ca can markedly reduce bitter 

 pit, cork spot and fruit breakdown during storage. 



Apply foliar sprays of CaCl^, beginning 3 weeks after petal 

 fall and repeat at 2 week intervals totaling 6 to 8 applications. 

 Apply & pounds CaCl-, per acre per spray until mid-July. After 

 mid-July apply S-lO^pounds per acre per spray. Continue foliar 

 CaCl2 until fruit are ready for harvest. Use a technical grade 

 of CaCl2 such as Allied Chemical Dow Flake, 77-801 CaCl2. Other 

 brands may be equally suitable. 



Experience in Massachusetts has shown that CaCl^ can be 

 combined with pesticide sprays. However, some growers have 

 observed that the combination of Cantan or Guthion [azinphos 

 methyl) 50 WP and CaCl^ may increase foliar burn. DO NOT MIX 

 CaCl2 AND SOLUBOR SPRAYS I ALWAYS DISSOLVE CaCl2 IN A PAIL OF 

 WATER and add this last, when the spray tank is nearly full, 

 to insure that the CaCl^ is completely dissolved before spray- 

 ing begins. 



Foliar CaCl^ sprays may be applied dilute (300 gallons/acre) 

 or up to lOX concentration (30 gallons/acre). In our research, 

 apple flesh Ca was increased more by concentrated than by dilute 

 sprays. In 1977, 6X and lOX foliar CaCl2 sprays were equally 

 effective in increasing Mcintosh flesh Ca. 



CaCl^ sprays can cause burn of leaf margins. Foliar injury 

 has been more serious on Mcintosh than on Delicious or Cortland. 

 Apple leaves are less susceptible to CaCl2 burn after mid-July. 

 Mcintosh growing on M7 may be more susceptible to foliar burn 

 than those on standard rootstock. Weak or injured trees may be 

 more susceptible to CaCl^ burn than heathy trees. To reduce the 

 chance of leaf burn, DO NOT REPEAT A FOLIAR CaCl^ SPRAY UNLESS 

 1 INCH OF RAIN HAS FALLEN SINCE THE LAST APPLICATION. 



In 1981, 3 different materials were used to supply foliar 

 Ca at the University of Massachusetts Horticultural Research 

 Center. Rate of application was that recommended by the manu- 

 facturer. Control, CaCl2, Carrier 1, and Carrier 2 supplied 

 a total of 0, 86, 64 and 16 grams Ca per tree in 8 applications. 



