22 CIRCULAR 659, U. S. DEPARTMENT OF AGRICULTURE 



to become infected with blue mold and in consequence are only suitable 

 for immediate consumption. It is not so commonly recognized that 

 apples with severe bruises should be culled out. Bad bruises not only 

 detract from the sales appeal of the fruit but are also potential avenues 

 of blue mold infection to almost the same extent as are skin punctures. 



Physiological Diseases 

 bitter PIT 



Bitter pit, Baldwin spot, or stippin, as it is variously called, is a 

 physiological disease found all over the world where apples are grown. 

 It appears as brownish spongy or corky spots or pits in the flesh just 

 under the skin and usually is most prevalent at the blossom end (fig. 6, 

 C). Occasionally the pits are deep-seated and are not evident without 

 cutting the apple. The affected part often has a somewhat bitter taste, 

 which accounts for the name. Bitter pit does not impair the keeping 

 quality of the apples, but, because the affected parts have to be pared 

 away, it reduces the value of the fruit, and, of course, detracts from its 

 appearance. 



No variety is entirety immune, but bitter pit is particularly prevalent 

 in Baldwin, Gravenstein, Arkansas (Mammoth Black Twig), Delicious, 

 Yellow Newtown, Rhode Island Greening, and Northern Spy. The 

 disease is most likely to occur in light-crop years, and apples grown on 

 young trees are particularly susceptible. Susceptibility to the disease 

 is also increased when late-season growth is stimulated by heavy irriga- 

 tion or rains, fertilization, heavy pruning, or other means. Bitter pit 

 may begin to appear before the apples are picked and seems to develop 

 to the greatest extent if they are picked before they reach proper ma- 

 turity, but as the disease is seldom fully manifested by the time of har- 

 vest it is impossible at that time to sort out all of the apples which will 

 show the pitting. Ordinarily, however, the diseased apples can be de- 

 tected within a month or 6 weeks after they are picked, and if susceptible 

 crops are held until then before sorting and packing the pitted fruit can 

 be eliminated. If this procedure were more generally followed, there 

 would be less likelihood of having to repack affected lots or suffer heavy 

 market losses because of bitter pit. 



JONATHAN SPOT 



Jonathan spot is a superficial skin disease characterized by small 

 black or brown spots resembling freckles scattered over the apple, par- 

 ticularly on the well-colored part (fig. 6, D). In later stages these spots 

 may become sunken and the flesh immediately beneath becomes brown 

 and spongy as the tissue dries out. The disease affects the appearance 

 and sales value of the fruit rather than its keeping quality. Jonathans 

 are very susceptible, but the disease occurs also on many other varieties. 

 The same kind of spot or one closely resembling it often seriously de- 

 tracts from the appearance of Rome Beauty apples. Jonathan spot is 

 only skin deep except in late stages, when underlying flesh tissue be- 

 comes brown and dried. 



