Winter McGtin^. 305 



diseases appear from time to time in addition to the old diseases 

 that have been known in different parts of the United States ever 

 since peach culture was begun. With simple gathering of the fruit 

 crop and no further attention until the next is ready to pick, the 

 diseases, like the crops, are a matter, of course. They express na- 

 ture's supposed method of growing these things. But man is an active 

 agent in the procedure. He introduces other conditions than the natural 

 ones, and by importation of stocks, etc., scatters the diseases or insects 

 found in centers of older culture to the newest and remotest portions 

 of the earth. Man has learned likewise to be a factor of another sort. 

 He has devised methods of prevention, which are very much needed 

 to maintain an equilibrium of forces. 



PEACH YELLOWS. 



The yellows is an American disease, which has been known for about 

 one hundred years. It attacks almond, apricot and nectarine trees as well 

 as the peach, and has been recorded upon Japanese plum trees. 



In the United States, Yellows is found in all the states east of the 

 Mississippi and north of the northern boundaries of Tennessee and North 

 Carolina, excepting Wisconsin and possibly some of the northern New 

 England states. It has not been found in the southern states. 



As yet, the specific cause of Yellows is unknown. The symptoms 

 are: First, premature ripening of the fruit, which is highly colored 

 and spotted, and has the flesh marbled with red ; second, premature 

 opening of winter buds. This may extend to fruit buds as well as 

 leaf buds, and has been observed as early as June and as late as No- 

 vember ; third, new buds develop on the trunk and branches and 

 grow into sickly looking shoots. 



The fruit may ripen as much as six weeks earlier than the normal 

 period, and oblique slices from the colored side will show the red 

 marbling of the flesh. The quality of the fruit is affected, being in- 

 sipid or mawkish. The symptoms may occur upon a single branch, 

 but when only a small portion of a tree shows the symptoms, the 

 whole tree is hopelessl}^ diseased, and should be treated as any other 

 tree that shows further development. Free blooming of yellows trees 

 may occur as late as November, though it is less frequent than the 

 unfolding of leaf buds in autumn. 



The branches from prematurely developed buds show many charac- 

 teristic forms of growth. The primary shoots may branch again and 

 again, to produce a broom growth of slender wiry twigs. A general 

 yellow color of the leaves is not a characteristic symptom of yellows, but 

 indicates more commonly some lack of vigor in the tree. In sandy soils 



H-20 



