MARKET DISEASES OF FRUITS AND VEGETABLES 55 



when the fruit is cut open, small winding tunnels extending deep 

 into the flesh are usually found (pi. 15, A). 



The rosy apple aphid (Anuraphis roseus Baker) also causes 

 a form of stigmonose. The insects feed on the newly formed, small 

 apples and cause apples to be very much stunted, knotty, distorted, 

 usually with a characteristic puckering of the surface around 

 the calyx end (pi. 2, H). The rosy apple aphid can be controlled 

 by any one of several different treatments applied during the 

 dormant or the "delayed dormant" period. Several of the so-called 

 DN compounds and tar-distillate oils are effective in killing the 

 aphid eggs. 



Since these materials are likely to cause injury to growing 

 plant tissue, the applications must be completed before the buds 

 start to swell. Rosy apple aphids may be controlled also by 

 application of a "delayed dormant" spray at the time when the 

 bud tips show green. The most effective spray consists of % to 

 1 pint of nicotine sulfate (40-percent nicotine) in 100 gallons of 

 water. The nicotine sulfate solution may be added to concen- 

 trated lime-sulfur if it is being used at this time for control of 

 San Jose scale. The oil sprays, which have to a considerable 

 extent replaced lime-sulfur for dormant spraying, are less de- 

 pendable for aphid control, but with the addition of nicotine they 

 are usually effective when applied in the "delayed dormant" 

 period. 



Current recommendations of the Bureau of Entomology and 

 Plant Quarantine or of State agricultural experiment stations 

 should be used as a guide in working out a control program for 

 this pest. 



Sunburn, Sunscald, and Delayed Sunscald 



"Sunburn" is the name applied to the condition of apples the 

 skin of which has become golden or bronzed on the side that has 

 been most exposed to the sun. This abnormal color detracts from 

 the appearance of the fruit, but normally the skin is not killed 

 and the tissues show no sign of break-down (pi. 3, E). 



True sunscald is found occasionally as white or tan-colored 

 spots, especially on apples that after being protected for some 

 time have been suddenly exposed to the sun. In severe cases, as 

 when an apple lying on the ground has been really scalded, the 

 skin and flesh present the appearance of having been held to a 

 flame (pi. 3, F). Such apples are, of course, rare on the market. 



Occasionally in storage apples are found with brown, somewhat 

 shriveled and sunken areas that were not in evidence when the 

 fruit was stored. Such conditions developing after harvest are 

 known as delayed sunscald and afford entrance points for decay 

 organisms such as the fungus causing alternaria rot. 



(See u.) 



Washing Injuries 

 (See Chemical Injuries, p. 23.) 



Water Core 



Water core occurs in practically all apple-producing sections 

 of the United States, but it is of greatest importance in those hav- 



