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Manganese Deficiency (Mn). This element is found deficient in several orchards each 

 summer. As shown in Figure 9, apple leaves having Mn deficiency have interveinal 

 fading of chlorophyll with the veins remaining green. In the past we have analyzed 

 Mcintosh apple leaves from trees showing Mn deficiency and found the leaf of this 

 element to be 9 to 14 ppm. Mn levels of this magnitude are critically low in comparison 

 to the desired standard of 50-100 ppm set by other states for apple trees. 



Manganese Toxicity (Mn) is implicated with the problem of "apple measles" shown 

 in Figure 10. The twig from Delicious at the top of the photograph shows severe 

 symptoms of measles while the twig below has normal bark. Measles can severely 

 injure or kill young Delicious trees. An over-application of a dormant-oil spray can 

 induce symptoms similar to that shown in Figure 10. 



Figure 9. Symptoms of manganese toxicity on apple leaves. 



