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MANGANESE (Mn) 



Mn is the most frequently deficient element in apple trees. Mn deficiency should 

 be corrected on trees showing considerable foliage damage. Although we have no 

 definite proof, Mn deficiency appeared to be associated with excessive fruit drop 

 on a few trees in orchard in 1977. Mn deficiency can be corrected by foliar applications 

 of manganese sulfate or of a fungicide containing Mn. Apply manganese sulfate at 

 about first cover at the rate of 3 lb per 100 gallons of water. If using a Mn-containing 

 fungicide, 2 or 3 applications are necessary with timings about petal fall, first and 

 second cover. 



BORON (B) 



B can be supplied to bearing apple trees either by foliar or soil applications. Use 

 the most economical and convenient method. However, it is safest to apply all elements 

 as a fertilizer except in emergency situations. 



Soil applications of boron should be applied to orchards every 3 years. The rate 

 of application per tree vary with tree age and size. In low density orchards, apply 

 1/4 lb of borax (11.1% actual B) or its equivalent under young trees coming into bearing, 

 1/2 to 3/4 pound to medium age and size trees and 3/4 to 1 lb to large or mature trees. 

 Be sure to note the percent actual B in the fertilizer being used to supply this element. 

 B containing fertilizers vary from approximately 11 to 21% actual B. 



In medium and high density orchards (115 trees/acre or higher), it might be best 

 to apply B on an acre basis. We suggest the following rates per acre of borax (11.1% 

 actual B) or its equivalent: (a) trees 4 to 7 years of age - 12 lbs; (b) trees 8 to 15 years 

 of age - 12 to 24 lbs; and (c) trees 16 to 30 years of age - 24 to 48 lbs. 



When the soil application of B is followed by a wet spring, it may be advisable to 

 apply 2 foliar applications of B the following year. 



Many growers now rely on annual foliar applications of B. The usual practice is 

 to add Solubor to the first 2 cover sprays. Fertilizer grades of borax may contain 

 grit and should not be used in a sprayer. Mature trees should receive 4 pounds of Solubor 

 per acre each year. Consequently, the goal is to apply about 2 pounds per acre in each 

 of the 2 applications. For young orchards, the addition of 1/2 pound of Solubor per 

 100 gallons (dilute basis) to the first 2 cover sprays meets the B requirements of these 

 trees. Reports of New York State indicate that sprays can be concentrated up to 8X 

 with satisfactory results. 



Leaf samples from orchards treated with Solubor have indicated adequate leaf 

 B levels but the fruit was deficient in this element. Whether or not B applied as a 

 fertilizer more adequately meets the B requirement of apples than foliar applied B 

 is not known to us. 



ZINC (Zn) 



Based on optimum levels of Zn established by Dr. Warren Stiles, Cornell University 

 (See FRUIT NOTES 47(2):20-26, 1982) some of our orchards continue to be low in this 



