THE USE OF BORON ON APPLE TREES IN THE 

 CHAMPLAIN VALLEY OF NEW YORK 



Arthur B. Burrell, Peru, N.Y. 

 Emeritus Professor of Plant Pathology, Cornell University 



The symptoms now recognized as those of boron deficiency evi- 

 dently have occurred here since the 1860's. Outbreaks of boron 

 deficiency symptoms usually have been related to drouth with losses 

 being minor in years of good moisture supply. However, on certain 

 sites, boron deficiency symptoms occurred every year and no orchard 

 of the area totally escaped losses from boron deficiency before 

 boron treatments were made. 



Now every fruit grower applies boron as crnsistently as he 

 applies nitrogen. This is regarded as insurance. The usual prac- 

 tice is to include Solubor*at the rate of one-half pound per 100 

 gallons in two sprays soon after petal-fall. When this is done 

 annually, the exact stage of development of the trees is not im- 

 portant. Usually one boron spray is applied about ten days after 

 petal-fall and the other at 20-30 days after petal-fall. The Solu- 

 bor is added to whatever pesticides are being used. No incompati- 

 bilities have been identified but deliberate experiments with some 

 of the newer pesticides have not been made. The grower usually at- 

 tempts to avoid extremely hot weather and to avoid applying it just 

 ahead of a heavy rain, but no critical tests of these factors have 

 been made. 



Pesticide spraying in this area usually is at 4X 

 tration. Burrell Orchards have used 8X for 14 years, 

 is correspondingly concentrated and the gallonage per 



to 6X concen- 

 The Sol ubor 

 tree reduced 



The aim is to apply about 

 cations. This results in 

 chards. When the tank is 

 (dilute spray basis), the 

 Pesticide sprayings seems 

 this is far below 4 pounds 



2 pounds per acre at each of the 2 appli 

 4 pounds per acre per year on mature or- 

 mixed at one-half pound per 100 gallons 

 amount received by young trees in normal 

 to meet their needs for boron, although 

 per acre on a very young orchrd. 



Mild i n jury 

 blast sprayer is 

 up mainly as white 

 extends a short distance 

 veins. This evidence of 

 mon if we were to put on 

 plication. 



to a few leaves close to the outlet of the air- 

 common but of no apparent significance. It shows 

 areas along the midrib. The white occasionally 

 out from the midrib along the principal 

 over-dose doubtlessly would be more com- 

 the required 4 pounds per acre in one ap- 



1 



Editors' note: Symptoms most frequently recognized by growers are 

 found in or on the fruit-- internal cork, pebbled surface of fruit, 

 open calyx or abnormally dark red color of red-skinned varieties 

 as they mature. Symptoms on the vegetative parts of the tree are 

 die-back of shoots and shoots with leaf rosettes. 



*Trade name 



