Recent Studies on Peach Yellows and Little Peach 57 



Summary 



Peach yellows and little peach are peculiar diseases of the peach 

 that are responsible for heavy losses in eastern peach districts. 

 Yellows appeared in the vicinity of Philadelphia as early as 1791. 

 Little peach was not definitely recognized until 1898. 



Losses 



In districts where yellows and little peach prevail 1 per cent of the 

 trees are likely to develop unmistakable symptoms annually in the so- 

 called quiet periods and 3 per cent is common, while during outbreaks 

 the number is likely to reach as much as 5 to 2? per cent. 



The United States Census for 1910 reports 15,508,921 hearing and 

 non-bearing peach trees for the states of New York, Xew Jersey. 

 Pennsylvania, Delaware and Maryland. A 3 per cent loss for this 

 territory would amount to 450,000 tree-. 



Periodical outbreaks of yellows have occurred in eastern peach 

 districts about once in 10 to 15 years, and several times have reduced 

 the industry to a low point. 



Symptoms of Advanced Staj>t*> «»t Yellows 



The outstanding symptoms of advanced stages of yellow- are: 

 ( 1 ) premature ripening and red spotting and blotching of die fruit: 

 (2) development of characteristic sickly, wiry shoots upon the twigs 

 and branches. Both symptoms ma\ appear at about the same time, 

 or one in advance of the other. 



Karli Preliminary Symptoms of Yellows 



Yellows and little peach ran often he recognized in the early or 

 preliminary stage-. 



The most reliable symptoms are a characteristic drooping oi the 

 leaves toward the branches with a slighl curling downward of the 

 tips' toward the petioles and sometimes a rolling inward of the mar- 

 gins. Such leaves are common]} of a lighter and more yellowish 

 green than normal leaves. 



Sometimes the presence of these diseases is firsi indicated by a 

 rolling of the leaves from the margins inward toward the midrib. 

 Such symptoms may he caused by other factors, however, and a care- 

 ful examination should be made of each case before making a decision. 



Vigorous trees affected by either yellows or little peach are in- 

 clined to push into growth earlier and bloom in advance of normal 

 trees and then quickly slow down in growth. 



