INSECTS AND DISEASES OF THE PEACH 1111 



yellows 



The cause of this disease is unknown. From the characters of 

 the disease it appears to be one of bacterial origin. It is con- 

 tagious to such an extent that whole orchards, or, as past records 

 show, the orchards of a whole section will become diseased and 

 gradually die out. This was the case in western New York about 

 thirty years ago, and at the present time it is true in the case of 

 certain districts of other states. 



The early character* of the disease is a premature peach, desig- 

 nated by bright-red dappled spots on the skin of the fruit. Such 

 specimens often develop in larger size than does the unaffected 

 fruit of the same tree, and they ripen earlier, showing the charac- 

 teristic blotches from two weeks before up to the 'day on which they 

 are ready to pick. The blotches appear to be concentrations of 

 juice just under the skin and form very slight pimples. The 

 quality is usually poor being a stringent insipid acid. It is inter- 

 esting to note the characteristic blotches and comparative size at 

 the time the premature fruits appear (Plate 3). A single 

 fruit on a branch or the fruits of an entire limb may show the 

 disease at the same time. In case the whole branch shows the 

 disease, the foliage becomes yellow as the season advances (Plate 

 1). During the second season the disease usually appears on 

 other limbs of the tree or over the entire tree. In the third year 

 less fruit sets, but both fruit and foliage have the colorations. 

 Terminal growth is checked and often wirelike shoots with nar- 

 row leaves appear on the large limbs and frequently on the small 

 branches (Plate 2). In the fourth year foliage is very scarce, 

 and death follows. Compare the normal streaking of the fruit 

 with the characteristic dapple (plates 3 and 4). 



Control. Trees in which the disease appears are doomed, as no 

 treatment has ever been found to improve their condition. The 

 only means by which the disease can be controlled is by systematic 

 examination and eradication of diseased trees in the orchards of a 

 community. The results obtained in the Niagara district between 

 1902 and 1913* illustrate the value of destruction of diseased 

 trees. The growers who practice removing the tree when the 

 disease first appears are the most successful in controlling the 

 disorder. 



* Bull. 61, 1014, X. Y. Dept. of Agr., Peach Yellow and Little Peach. 



