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MANUAL OF FRUIT DISEASES 



the number of peach trees destroyed by yellows between the 

 years 1874 and 1890 is estimated at more than one-half 

 million. 

 Symptoms. 



The marked symptoms of peach-yellows consist (1) in a 

 premature ripening of the fruit (Fig. 76) ; (2) a red spotting 

 on the surface of the fruit ; (3) the development of secondary 

 shoots in great numbers (Fig. 77), these being dwarfed and 



unhealthy in appear- 

 ance; (4) the de- 

 velopment of short 

 shoot-axes with 

 sickly foliage of a 

 yellowish or red- 

 dish brown color, 

 having a tendency 

 to roll sidewise. 

 These symptoms be- 

 gin to develop in 

 the middle of the 

 summer. Subsequent developmental stages are observed at 

 various seasons of the year. 



Certain evidences of yellows are apparent the first year that 

 the orchard is affected. (1) There is a premature ripening of 

 the fruit (Fig. 76) ; this, will likely be the first noticeable symp- 

 tom. This premature ripening may take place a few days 

 to several weeks prior to the time of normal ripening. It may 

 occur on but one or two branches, in which case the peaches on 

 the rest of the tree ripen normally, or all peaches on an affected 

 tree may exhibit this abnormality. This phenomenon should 

 never be confused with the work of the peach-tree borer ; trees 

 severely injured by this insect may ripen their fruit prematurely, 

 but the flesh is never red spotted and shoots are not put forth 

 as in yellows. (2) Diseased fruits are always reddish or pur- 



FIG. 76. Peach-yellows ; on the right small 

 healthy peaches, on the left large prematurely 

 ripened fruit. 



