MAEKET DISEASES OF APPLES, PEARS, QUIITCES 29 



a uniform brown color, it will be hard to determine whether the 

 condition is freezing injury or internal breakdown. Reliance should 

 then be placed, not on any one symptom or the examination of one 

 apple, but on all the symptoms that can be found, in as many apples 

 as can conveniently be examined. 



Water-soaked bruises are not a sure sign of freezing injury, as 

 will be seen by reference to Bruises, page 15. (^^, 36, 62, 86, 129, 198, 

 240.) 



FREEZING INJURY WHEN APPLES AND PEARS ARE YOUNG 



When freezing temperatures occur at blossoming time or soon 

 afterwards, the fruits that remain on the trees may nevertheless 

 have suffered sufficient injury so that as they come to maturity they 

 show various abnormal conditions. One of these conditions is the 

 familiar " frost russet ", which on apples may appear as narrow 

 bands extending from the blossom end to the stem end of the fruit 

 (pi. 6, D), or as a russeted ring lining the calyx cavity and occa- 

 sionally extending outward from the cavity for a half inch or more. 

 On pears it most commonly takes the form of bands encircling the 

 fruit about half-way between the two ends. In addition, frost russet 

 on both pears and apples sometimes has the diffuse irregular form 

 characteristic of spray injury and rain russet. 



A second condition, seen less frequently and then only on apples, 

 is a persistence of the green color at the blossom end on mature 

 fruits which over the rest of their surface have the color normal to 

 the variety (pi. 10, E). The greening varies greatly in intensity 

 and in the amount of surface covered. It may or may not be accom- 

 panied by russeting. Affected areas are occasionally so flattened and 

 so dark green that they look like apple-cedar rust spots, but they do 

 not, of course, show the pustules characteristic of rust. Badly dam- 

 aged specimens are nearly always distorted at the blossom end, may 

 have only a few poorly developed seeds or none at all, and usually 

 show in cross or longitudinal section a blotchy or streaked browning 

 in the flesh underlying the green areas (pi. 10, E, F). 



FRUIT SPOT 



(MycospJiaerella •pomi (Pass.) Lindau) 



Fruit spot (" Brooks' spot ") in the United States is most common 

 in the region east of Michigan and north of North Carolina and 

 Tennessee, but it is occasionally serious in southwestern Missouri and 

 northwestern Arkansas. It causes the greatest losses in New Eng- 

 land, where 50 to 90 percent of the fruit may be affected in years 

 when the disease is bad. In late years it has been one of the most 

 important diseases in New Jersey. The disease also occurs in Can- 

 ada and has recently been reported from Germany and South Africa. 

 Varieties most seriously affected are Baldwin, Jonathan, Kome 

 Beauty, Tolman Sweet, Grimes Golden, and Stayman Winesap, 

 although many others have been reported as susceptible. 



The spots are one eighth to one fourth of an inch in diameter and 

 are deep red or black on red areas and dark green on gTeen or yellow 

 areas (pi. 3, A). The center of the spot is flecked with black, which 



