588 THE PEACH. 



The soil does not appear materially to increase or lessen the liability 

 to the Yellows, though it first originated, and is most destructive, in 

 light, warm, sandy soils. 



Lastly, it is the nearly universal opinion of all orchardists that the 

 Yellows is a contagious disease, spreading gradually, but certainly, from 

 tree to tree through whole orchards. It was conjectured by the late 

 William Prince that this takes place when the trees are in blossom, the 

 contagion being carried from tree to tree in the pollen by bees and 

 the wind. This view is a questionable one, and it is rendered more 

 doubtful by the fact that experiments have been made by dusting the 

 pollen of diseased trees upon the blossoms of healthy ones without 

 communicating the Yellows. 



We consider the contagious nature of this malady an unsettled 

 point. Theoretically, we are disinclined to believe it, as we know 

 nothing analogous to it in the vegetable kingdom. But on the other 

 hand it would appear to be practically true, and for all practical pur- 

 poses we would base our advice upon the supposition that the disease is 

 contagious. For it is only in those parts of the Atlantic States where 

 every vestige of a tree showing the Yellows is immediately destroyed, 

 that we have seen a return of the normal health and longevity of the 

 tree. * 



Cause of the Yellows. No writer has yet ventured to assign a 

 theory, supported by any facts, which would explain the cause of this 

 malady. We therefore advance our opinion with some diffidence, but 

 yet not without much confidence in its truth. 



We believe the malady called the Yellows to be a constitutional taint 

 existing in many American varieties of the Peach, and produced, in the 

 first place, by bad cultivation and the consequent exhaustion arising 

 from successive over-crops. Afterwards it has been established and 

 perpetuated by sowing the seeds of the enfeebled tree, either to obtain 

 varieties or for stocks. 



Let us look for a moment into the history of the Peach culture in 

 the United States. For almost a hundred years after this tree w T as in- 

 troduced into this country it was largely cultivated, especially in Vir- 

 ginia, Maryland, and New Jersey, as we have already stated, in perfect 

 freedom from such disease, and with the least possible care. The great 



* The following extract from some remarks on the Yellows by that careful 

 observer, Noyes Darling-, Esq. , of New Haven, Ct. , we recommend as worthy the 

 attention of those who think the disease contagious. They do not seem to 

 indicate that the disease spreads from a given point of contagion, but breaks 

 out in spots. It is clear to our mind that in this, and hundreds of other 

 similar cases, the disease was inherent in the trees, they being the seedlings of 

 diseased parents. 



" When the disease commences in a garden or orchard containing a consider- 

 able number of trees, it does not attack all at once. It breaks out in patches 

 which are progressively enlarged, till eventually all the trees become victims to 

 the malady. Thus, in an orchard of two and a half acres, all the trees were 

 healthy in 1827. The next year two trees on the west side of the orchard, within 

 a rod of each other, took the Yellows. In 1829, six trees on the east side of the 

 orchard were attacked ; five of them standing within a circle of four rods 

 diameter. A similar fact is now apparent in my neighborhood. A fine lot of 

 200 young trees, last year in perfect health, now show disease in two spots near 

 the opposite ends of the lot, having exactly six diseased trees in each patch con- 

 tiguous to each other ; while all the other trees are free from any marks of dis- 

 ease. " Cultivator. 



