- 9 - 



(Photograph by Russell Mariz, Photo 

 Center, UMass. ) 



will 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 resem- 

 bles 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. 



Cortland continued to be troublesome in some orchards because o£ 

 its susceptability to bitter pit, and a few orchardists were concerned 

 this fall about this disorder on Mcintosh. 



It is very difficult to increase Ca content of apple trees 

 and fruit. Although foliar sprays of Ca solutions have been shown 

 to reduce bitter pit, they have not eliminated it. A major problem 

 is that Ca in the soil moves very slowly into the tree and most 

 of it is quickly tied up in an insoluble form. We suggest the 

 following measures to increase Ca content of apple leaves and fruits. 



A. Continue to apply 3 tons of limestone per acre every 2 

 to 3 years. Where high magnesium lime was used in the last 

 application, the use of a more soluble high Ca, low Mg lime 

 (5-71 MgO) will act more rapidly and will provide more Ca. 



B. Use calcium nitrate as the source of nitrogenous ferti- 

 lizer. Calcium nitrate increases the level of soluble soil 

 Ca more quickly, increases the downward movement of Ca and 

 raises the pH of the soil. 



C. Apply foliar sprays of calcium chloride (CaCl2) starting 

 about 3 weeks after petal fall and repeat at 2-week inter- 

 vals, totalling 6 to 8 applications. Apply 6 to 8 pounds 

 CaCl2/acre/spray until mid-July. After mid-July, apply 



10 pounds/acre/spray. Sprays may be applied dilute or on a 

 trial basis up to 6X concentration. Growers desiring to 

 paCl2 with their cover sprays should do it on a tri al 

 When combining with cover sprays , add CaCl2 last to 



com bine 

 ba sis 

 the 



only, 



spray 



