Phosphorus ; P deficiency can reduce tree growth and yield, 

 and in several parts of the world it has also been shown to cause 

 increased amounts of breakdown of apples during storage. However, 

 in North America there has been very little evidence for P defic- 

 iency in fruit. However, we have recently found that high levels 

 of P in apples, especially in combination with low levels of Ca , 

 greatly increased breakdown of apples during storage. 



Boron : B deficiency has occurred over much of North America, 

 causing both internal and external cork development in fruit. Ex- 

 cessive levels of B in fruit can cause earlier maturation and 

 increased amounts of watercore at harvest, and increased amounts of 

 breakdown after storage. Thus, a moderate level of B is important 

 for good fruit quality. 



B also influences Ca movement in the tree. If it is deficient, 

 less Ca is moved to the fruit and Ca deficiency can result. It 

 is therefore important to maintain adequate B levels as a part of a 

 program to avoid Ca deficiency. 



Periodic application of borax to the soil is a standard commer- 

 cial practice in many parts of North America. A widely used alter- 

 native is 1 or 2 foliar applications of a soluble form of B in sprays 

 shortly after blossoming, although it is not clear how much of this 

 B moves from leaves into the fruit. 



It is clear that deciding on a fertilizer program for an orchard 

 is no simple matter. The awareness that Ca deficiency is common and 

 that it greatly increases losses of stored fruit has caused a thor- 



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SUGGESTIONS FOR USE OF CALCIUM SPRAYS IN 1980 



Mack Drake 

 Department of Plant and Soil Sciences 



Calcium chloride (CaCl„) foliar sprays are recommended for 

 all growers, to increase the flesh Ca content of Massachusetts 

 apples. Higher flesh Ca can markedly reduce pit, cork and storage 

 breakdown . 



Apply foliar sprays of CaCl„, starting about 3 weeks after petal- 

 fall and repeat at 2 week intervals totalling 6 or 8 applications. 

 Apply 6 pounds CaCl„ per acre per spray until mid-July. After mid- 

 July apply 8 to 10 pounds/acre spray. Use a technical grade CaCl^ 

 such as Allied Chemical Flakes, 77-80% CaCl^. Other brands may be 

 equally suitable. 



