260 Peach-Growing 



Peach-yellows (Cause unknown) 



This disease has long been a serious menace to the peach 

 industry. The regional progress of the disease has been 

 gradually southward, now having reached as far as North 

 Carolina and Tennessee, and w^estward to the Mississippi 

 River. In all of the important peach-growing districts 

 within the area thus indicated, this disease has in the past 

 wrought unmeasured havoc, entire orchards and the interests 

 in whole communities having been destroyed thereby. 

 This, however, was before its infectious or contagious 

 character was understood and methods of control established. 

 The cause of the disease and the means by which it is spread 

 have never been determined. 



Course of development 



Usually the first evidence of yellows in a bearing tree is 

 the premature ripening of the fruit ; ripening may occur from 

 a few days to possibly two weeks or more in advance of the 

 normal time. Usually this occurs first on a part of the tree, 

 frequently on only a single limb, while the fruit on the 

 remainder of the tree appears perfectly normal in all respects. 

 The premature fruit usually shows characteristic small 

 red spots on the surface which mark the location of red 

 streaks that extend to the pit. jMoreover, such fruit, es- 

 pecially if it ripens considerably in advance of its normal 

 time, is usually small, insipid, sometimes bitter and al- 

 together undesirable. 



Other symptoms follow in succession. The next year 

 the entire tree may ripen its fruit prematurely and begin 

 to show lack of vigor and thrift. Adventitious buds develop 

 on the trunk and larger limbs from which grow slender, 



