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



extends inward in roughly triangular patches as far as the 

 vascular bundles or a little beyond; next to this is another zone 

 of healthy flesh, and in the flesh at the core is a second area of 

 brown. The condition just described is especially common in 

 Jonathan and Delicious. The riper side of the apple is affected 

 more often than the greener side and the calyx half more often 

 than the stem half. The skin of affected fruits may be normal 

 in appearance, but it is often duller and darker than normal and 

 in later stages of the disease it sometimes becomes cracked. 



Apple flesh affected with internal break-down is usually mealy 

 rather than wet and soggy. (See Soggy Break-Down, p. 51.) 



Internal break-down is at times mistaken for freezing injury 

 (p. 33). In distinguishing the two, it is helpful to bear in mind 

 that a large part of the browning in frozen apples occurs at 

 bruises extending inward from the surface and that freezing in- 

 jury may occur anywhere in the apple without relation to 

 maturity or morphology; and that, on the other hand, browning 

 from internal break-down at a bruise rarely assumes a radial 

 direction, is usually accompanied by a greater degree of mealiness, 

 and includes more of the surrounding tissue. 



Internal break-down occurs most often on large-size, over- 

 mature apples and on those that have been forced late in the 

 season. It sometimes results from holding the fruit on the trees 

 too long, waiting for color, and can often be traced to delay in 

 cooling the fruit after it has been harvested or to the fact that 

 the fruit has been held in storage at too high a temperature or 

 beyond its proper season. Internal break-down also often follows 

 water core, as previously stated, and for this reason it is usually 

 considered hazardous to store water-cored apples. The amount 

 and seriousness of internal break-down vary from year to year, 

 apparently being dependent to a large extent upon growing 

 conditions. 



The little that can be done to control internal break-down after 

 picking is best done by placing fruit promptly in cold storage at 

 30° to 32° F. ; but fruit with a decided tendency toward break- 

 down cannot be relied on for late keeping even in cold storage. 



(See 12, 59, 92, 98, 105, 108, 1U, 136.) 



Internal Browning 

 (See Brown Core and Internal Browning, p. 18.) 



Jonathan Spot 



Jonathan spot occurs on apples grown in all parts of the United 

 States and is also known to occur in other parts of the world. The 

 variety most commonly affected is the one on which the disease 

 was first described, Jonathan; other varieties showing spots so 

 similar that they are generally classed as Jonathan spot are 

 Esopus Spitzenburg, Wealthy, Yellow Newtown, Grimes Golden, 

 Rome Beauty, Gravenstein, Ortley, Arkansas Black, Twenty 

 Ounce, and Wolfriver. The spotting is apparently not caused by 

 either fungi or bacteria. It is common after a dry season and in 

 some years is more common on large apples than on small ones. 

 It is occasionally found on ripe apples before picking, but it is 



