52 MISC. PUBLICATION 168, U. S. DEPT. OF AGRICULTURE 



to be distinct as to both characteristics and cause. Jonathan, 

 Northwestern Greening, Grimes Golden, Wealthy, and Golden 

 Delicious are very susceptible to the disease. 



Soggy break-down is first evident as light-brown areas in the 

 cortical region of the apple. The discoloration may continue until 

 a large part of the cortex is involved and a complete ring of soft 

 brown tissues has formed (pi. 9, A, B). The affected flesh is 

 sharply delimited from the normal and is typically moist and 

 soggy, although sometimes it becomes mealy when the disease is 

 in an advanced stage. Adjacent sound tissue usually has a char- 

 acteristic fermented taste. The skin of the apple may appear 

 normal except in the later stages of the disease, but affected fruit 

 can be detected by a characteristic sponginess due to the under- 

 lying soft tissue. 



Soggy break-down is akin to soft scald in the conditions respon- 

 sible for its occurrence. It is more prevalent on apples stored at 

 30° F. than on those held at 32° and is usually completely pre- 

 vented by storage at 36° to 40°. It is generally increased greatly 

 by delaying storage. 



Holding apples in an atmosphere containing 20 to 30 percent 

 of carbon dioxide for 2 days during the cooling period has largely 

 or entirely prevented the later develooment of soggy break-down. 



(See 16, 17, 104, 107, 108, 109.) 



Sooty Blotch 

 (Gloeodes pomigena (Schw.) Colby) 



Sooty blotch is marked by sooty patches or spots, very irregu- 

 lar in size and shape, which may occur on any part of an apple 

 (pi. 1, F). They are easily removed by scraping or by moistening 

 and wiping the apple. On Kieffer pears the blotches are often 

 surrounded by a russet zone. The causal fungus does not cause 

 decay or even browning of the tissues under the spots, but 

 affected fruits are sometimes badly wilted. The chief loss is due 

 to blemishing by the fungus and consequent reduction in the 

 market value of the fruit. 



Sooty blotch is common throughout the central and eastern 

 apple-growing sections of the United States, but is rare in the 

 Northwest. All late-summer and winter varieties may be affected. 



The disease does not develop or spread in transit or storage 

 and is of minor importance on the market. It is controlled by 

 spraying with bordeaux mixture or ferbam as recommended by 

 the local agricultural experiment station. 



(See 59, 65, 11 1*.) 



Spongy Dry Rot 

 (Colletotrichum fructus (F. L. Stevens & Hall) Sacc.) 



Spongy dry rot has been reported to cause loss in North Caro- 

 lina, Massachusetts, New York, West Virginia, Pennsylvania, and 

 Indiana, usually on fallen fruits. It is rare on the market. 



In early stages the disease appears as small black spots scat- 

 tered over the surface of the fruit. Later, as these enlarge, they 

 coalesce and form black sunken areas, */2 to 1 inch or even more 

 in diameter, which eventually become roughened by the fruiting 

 bodies of the fungus. Affected areas resemble those produced 



