92 Diseases of Economic Plants 



be set in the places from which diseased trees have been 

 removed. 



Recognition marks, which leave no uncertainty as to its 

 identity, are described by Smith as follows: "Prematurely 

 ripe, red-spotted fruits, and premature unfolding of the 

 leaf buds into slender, pale shoots, or into branched, broom- 

 like growths, are the most characteristic 

 symptoms of yellows. The time of ripen- 

 ing of premature fruit varies within wide 

 limits; sometimes it precedes the nor- 

 mal ripening by only a few days, and at 

 other times liy several weeks. The red 

 spots occur in the flesh as well as on the 

 skin, making the peach more highly col- 

 ored than is natural. The taste of the 

 Fig 47. — Mildew ^^""^^ ^^ generally inferior and often in- 

 upon peach fruit, sipi^l, mawkish, or bitter. Often this 

 After Bailey. premature ripening is the first sjanptom 



of yellows. The peaches are then of good 

 size and quite showy, and occur on trees in full vigor, upon 

 limbs bearing abundant green foliage, and sometimes also 

 other fruits which afterward ripen normally. 



"Often during the first year of the disease this kind of fruit 

 is restricted to certain limbs, or even to single twigs, which, 

 however, do not differ in appearance from other limbs of the 

 tree. The following year a larger part of the tree becomes 

 affected and finally the whole of it, the parts first attacked 

 now showing additional symptoms, if they have not already 

 done so. These symptoms are the development of the 

 winter buds out of their proper season. Like the prematur- 

 ing of the fruit, the date of this also varies within wide limits. 

 The buds may push into shoots only a few days in advance 

 of the proper time in the spring, or may begin to grow in 

 early summer, soon after they are formed, and while the 

 leaves on the parent stem are still bright green. This is a 

 very common and characteristic symptom, and is especially 

 noticeable in autumn when the normal foliage has fallen. 



