24 MISC. PUBLICATIOX 16 8, U.S. DEPT. OF AGRICTJLTUEE 



temperature in the orchard. Although these forms of injury cause 

 appreciable loss at times in the orchard, they are only occasionally 

 found on the market. 



Control of the diseases depends, obviously, on preventing drought 

 conditions whenever possible and. maintaining a healthy, vigorous 

 root system, capable of supplying the moisture required by the tree. 

 {2o, 100, 150.) 



DROUGHT SPOT 



Drought spot is known to occur in many parts of the United 

 States, but has been seen on the market chiefly on apples from the 

 Xorthwest. The varieties most often affected are Winesap, Stayman 

 Winesap, and Delicious. Ben Davis, White Pearmain, and certain 

 other varieties, if exposed to the same drought conditions, will wilt 

 or shrivel instead of becoming affected with drought spot. 



The disease is exhibited in oblong to roughly circular areas, usually 

 not more than a fourth of an inch across and always somewhat 

 sunken below the surrounding fruit surface (pi. 7, A, E). The 

 skin color in these areas either is not changed or is somewhat darker 

 than that normal for the variety. Browning may occur beneath the 

 skin but rarely extends to a depth of more than a sixteenth of an 

 inch ; occasionally brown streaks follow the water-conducting vessels 

 deeper into the pulp (pi. 5, D). 



In early stages (practically never seen on the market) the disease 

 ajDpears as large, irregular, water-soaked spots that often have a 

 reddish margin and are usually covered with drops of oozing sap 

 which is sweetish, yellow, and sticky at first, later becoming hard 

 and brittle. 



Drought spots may occur on any part of the fruit surface; they 

 differ in that respect from bitter pit, which usually occurs on the 

 blossom half of the fruit, and from hail injury, which is almost 

 always restricted to one side or one end. The roughly circular outline 

 of drought spots distinguishes them from the creases produced by 

 the pressure of twigs or small limbs while the fruit is developing. 



The disease is caused by sudden and severe drought and obviously 

 is to be controlled by preventing the occurrence of drought condi- 

 tions whenever possible. {22, 25, 100, ISO, 195.) 



FLYSPECK 



{LeptofJiyriuni pomi (Mont, and Fr.) Sacc.) 



Flyspeck (pi. 3, C) is well described by its name. The specks 

 occur in areas usually not more than half an inch in diameter 

 and are as easily scraped off as sooty blotch. The two diseases are 

 usually associated, but are caused by different fungi. 



Flyspeck is of importance on the market only because of its effect 

 on the appearance of the fruit. It can be controlled by the treatment 

 recommended for scab. {100, lU, 161, 183.) 



FREEZING INJURY 



Freezing injury is a common source of loss in apples during the 

 winter months. The greater portion of it occurs in transit, especially 

 in fruit shipped from the Pacific Coast States, which must pass 



