-6- 



has cork spot. Bitter pit is most frequently associated with the calyx end of the apple 

 and its severity may increase in storage. Cork spot is not localized and will appear 

 anywhere on the apple. The spots are more pronounced than bitter pit, being much 

 deeper and wider. In some cases the cork spot resembles the inner cone of a miniature 

 volcano, with the depressed skin area containing green or dark red pigment. Cork 

 spot does not increase in severity in storage. 



Magnesium (Mg) Deficiency. Mg deficiency of apple and pear trees has been more 

 prevalent in orchards the last 2 years probably due to excessive rainfall early in the 

 growing season. These visual observations were supported by leaf analysis which 

 indicates that Mg is exceptionally low in some instances. 



Mg symptoms are characterized necrotic (brown) areas between the veins (Figures 

 2, 3). The older basal leaves on shoots and spurs are usually affected first and as the 



Figure 2. Magnesium deficiency symptoms on apple leaves. 



