11 - 



base of the leaf blade. In severe cases, 

 loss of chlorophyll is more extensive than 

 shown in the picture; marginal leaf scorch 

 develops, leaves absciss, and wood injury 

 can occur. 



B def 

 toxicity, 

 deficiency 

 characteri 

 shaped les 

 The dead c 

 corky befo 

 the disord 

 (particula 

 open calyx 

 they matur 

 first reco 

 cessive pr 



iciency is more common than B 

 The most common symptom of B 

 is found in the fruit being 

 zed by brown, round or irregular 

 ions of about 1/4 inch diameter, 

 ell masses become dry, hard and 

 re harvest. Fruit affected with 

 er will have a pebbled surface 

 rly noticeable on Cortland) , 

 and abnormally dark color as 

 However, frequently the 

 gnition of the problem is ex- 

 eharvest drop. 



e. 



B can be supplied to 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 

 m emergency situations . 



Soil applications of boron should be applied to orchards 

 every 3 years. The rates of application per tree vary with tree 

 age and size. In low density orchards, apply 1/4 pound of borax 

 (11.11 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 pound 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 fol- 

 lowing 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 



