-in- 



Tree requirements for K. K„0* needed to meet the K requirements based on potential 

 yields are as follows: (a) less than 15 bushels: 1.3 lbs/tree; (b) 15 to 25 bushels: 1.3 

 - 2.7 lbs/tree; and (c) more than 25 bushels: 2.7 - 4.3 lbs/tree. The K„0 requirements 

 can be supplied by applying muriate of potash, a "complete" fertilizer or Sulpomag**. 

 Increasing the K level in the trees will further reduce IVIg. Therefore, Sulpomag is 

 suggested when trees are low both in K and Mg because the elements must be kept 

 in balance. This fertilizer contains not less than 21% of potash (K2O), nor less than 

 53% of sulfate of magnesia. Mature trees below normal in K will require 200-300 

 of K or 600 lbs of Sulpomag per acre. FERTILIZERS SIMILAR TO SULPOMAG MAY 

 BE AVAILABLE AND EQUALLY SUITABLE. 



CALCIUM (Ca) 



If Ca is below normal, continue to apply 3 tons of limestone per acre every 2 to 

 3 years. Where high magnesium lime was used in the last application, the use of a 

 more soluble high Ca, low Mg lime (5 - 7% MgO) will act more rapidly and will provide 

 more Ca. 



Apply foliar sprays of CaCl2, beginning 3 weeks after petal fall and repeat at 2 

 week intervals totaling 6 to 8 applications. Apply 6 pounds CaCl2 per acre per spray 

 until mid-July. After mid-July apply 8-10 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, 77-80% CaCl2. Other brands may be equally suitable. 



Experience in Massachusetts has shown that CaCl2 can be combined with pesticide 

 sprays. However, some growers have observed that the combination of Captan or 

 Guthion (azinphosmethyl) 50 WP and CaCl2 may increase foliar burn. DO NOT MIX 

 CaCl2 AND SOLUBOR SPRAYS! ALWAYS DISSOLVE CaCl2 IN A PAIL OF WATER 

 and add this last, when the spray tank is nearly full, to insure that the CaCl2 is 

 completely dissolvedbefore spraying begins. 



Foliar CaCl2 sprays may be applied as 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. 



CaCl2 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 

 CaCl2 burn than healthy trees. To reduce the chance of leaf burn, DO NOT REPEAT 

 A FOLIAR CaCl2 SPRAY UNLESS ONE-HALF TO ONE INCH OF RAIN HAS FALLEN 

 SINCE THE LAST APPLICATION. 



We also urge growers to seriously consider supplementing CaCl2 sprays with 

 post-harvest CaCl2 dips or drenches especially fruit intended for long-term storage. 

 A postharvest Ca application is viewed as a food-additive process by the Food and Drug 

 Administration. That agency has stipulated the "Brining Grade" CaCl2 containing 94% 

 CaCl2 is acceptable for postharvest use. The technical flake CaCl2 commonly used 

 for tree sprays is still acceptable for tree sprays, but it may not be used for postharvest 

 treatments. Therefore, anyone wishing to use postharvest CaCl2 treatments must obtain 

 the Briner's Grade material, which is now readily available from suppliers. 



* 

 Potassic fertilizers are usually guaranteed in terms of their content of the oxide of 



potassium (K2O). The commonly used potash salts are the refined muriate or chloride 



containing 50-60% K2O. 

 ** 



Trade name 



