MARKET DISEASES OF FRUITS AND VEGETABLES 11 



attack Delicious, Mcintosh, Winesap, and Yellow Transparent 

 apples, producing dwarfing, distortion, and an internal condition 

 which affects more of the fruit tissue than apple-cedar rust does. 

 Aecia are not usually produced. Only occasionally do affected fruits 

 reach the market. The affected surface tissue is deeper green 

 than the normal skin color (pi. 2, B) instead of yellow like that 

 affected with apple-cedar rust. 

 (See 88.) 



Bitter Pit 



Bitter pit occurs in all the important apple-growing regions 

 of the world. In the United States it may be found on practically 

 all varieties of apples, but it is not of commercial importance on 

 all. Baldwin, Northern Spy, Rhode Island Greening, Grimes 

 Golden, Tompkins King, Yellow Newtown, York Imperial, Rome 

 Beauty, Winter Banana, Stayman, Arkansas (Mammoth Black 

 Twig), Arkansas Black, Delicious, and Gravenstein are among 

 the more susceptible varieties. 



In its usual form the disease is characterized by sunken spots, 

 about y 16 to Ys inch in diameter, distributed over the calyx half 

 of the apple. The spots resemble small bruises and are some- 

 times wrongly ascribed to hail injury. In the early stages they 

 have a water-soaked appearance, but later they become more 

 highly colored than the surrounding fruit surfaces, taking on a 

 deep-red color on blush areas and remaining bright green on 

 green or yellow surfaces. They finally become brown, gray, or 

 sometimes black and are somewhat sunken (pi. 4, A). When the 

 apple is peeled or cut, numerous spots and streaks of brown 

 spongy tissue become evident just beneath the skin (pi. 4, B). 

 Bitter pit spots, though closely associated with the terminal 

 branches of the vascular bundles, or food- and water-conducting 

 system, of the apple, are not confined to the region immediately 

 beneath the skin, but may occur deep in the flesh. The affected 

 tissue often has a bitter taste. 



On apples of the Yellow Newtown variety the spots may be 

 more prevalent on the cheek than on the blossom end and are 

 usually rather sharply sunken. In addition, they are more nearly 

 circular in outline than those of the common form just described. 

 The skin covering the depressed areas usually varies in color from 

 gray to dark brown or black. Occasionally such spots have a more 

 or less complete border of blackened skin that is only slightly 

 depressed, if at all, below the level of the healthy skin. 



Bitter pit spots on the Winter Banana are frequently large 

 and sharply sunken, and in such cases they have the appearance 

 of having been formed by the coalescence of several smaller 

 spots; sometimes they comprise areas % to 1 inch long and of 

 varying width. 



A condition on York Imperial apples in the Shenandoah-Poto- 

 mac valley districts known as York spot is here considered to be 

 a form of bitter pit. It develops while the fruits are on the trees 

 and results in an appearance different from that of the usual 

 bitter pit on other varieties. While York spot is not definitely 

 known to be bitter pit, there seems to be good evidence that it 

 is; namely, it is induced by the same conditions in the orchard 



