Recent Studies on Peach Yellows and Little Peach 13 



The authors are led to believe that some nurserymen and many 

 budders employed by nurserymen are unable to recognize the early 

 symptoms of the disease. All who are responsible for the propaga- 

 tion and growing of peach stock should be familiar with the early as 

 well as the advanced symptoms of these diseases. 



Workers who have made a study of peach yellows and little peach 

 fully appreciate that in order to make a positive diagnosis of these 

 diseases in trees before they come into bearing necessitates a close 

 study of the subject. Observations at the New Jersey station have 

 led to the determination of certain early symptoms that indicate the 

 probable presence of these diseases before the well defined or ad- 

 vanced symptoms appear. The results of this work were published in 

 Bulletin 226 of the Agricultural Experiment Station in January, 

 1912. Previous to 1912, all of this work was under the supervision 

 of the senior author, but beginning with 1912, the work has been car- 

 ried on cooperatively by members of the departments of horticulture 

 and plant pathology. 



Symptoms of Advanced Stages of Yellows 



Before entering into a discussion of the investigations with these 

 diseases it may be well to note the symptoms attributed to them. The 

 following symptoms have been commonly regarded as indicating that 

 a tree is unquestionably affected with yellows. 



Premature Fruit 



The fruit on diseased trees may ripen from a few days to three 

 weeks in advance of the normal time of ripening of the variety. 

 Such fruit is commonly more or less red spotted and blotched with 

 color, rather than normally blushed, marked and washed with red as 

 shown in figure 5. These spots and blotches of color may occur 

 largely in the skin of the fruit or through the flesh to the pit. The 

 flesh also is more prominently marked with red around the pit than 

 is the case with normal fruit. The flavor of the diseased fruit may 

 vary from nearly normal to insipid or bitter. The fruit may be 

 larger or smaller than on normal trees, depending upon the condi- 

 tions which will be described later. The premature fruit is very 

 susceptible to attacks of brown rot, probably because the skin of such 

 premature fruit is less resistant than that of normal fruit. 



