42 EEPOET OF THE COMMISSIONEE OF AGRICULTURE. 



from the same sources as other "trees which have been destroyed by the 

 disease. 

 Trees grown under a glass roof have every opportunity to finish and 



perfect their growth ; the leaves assume the various tints of autumn 

 coloring and drop in a natural manner as their duties are brought to u 

 close, and wherever peach trees, when in a normal condition, whether 

 North or South, evidence a completion and maturation of growth by n 

 gradual change of their foliage from green to other colors, varying in 

 diOerent varieties, there the peach tree will remain healthy and no 

 danger need be apprehended of yellows. 



Duriug the summer and fall of 1858 I had occasion to pass, several 

 times each month, through a part of the county of Middlesex, New Jer- 

 sey, and the course of my journey led me past a very beautiful peach 

 orchard of some 20 acres or more in extent and apparently about three 

 years planted. The soil was good and the culture seemed perfect; the sur- 

 face was clean and no weeds to be seen. The deep green color of the fol- 

 iage over the whole orchard, so far as could be seen, was well calculated to 

 arrest attention, and this lively color was retained until it was suddenly 

 struck with frost. I had i^assed it the evening before the frost occurred ; 

 next morning, at a place some 12 or 15 miles further north, I observed 

 that the themometer indicated IL degrees of frost. Three days after- 

 wards I again passed this orchard ; some few of the leaves had dropped, 

 but they mostly remained on the trees somewhat blackened in color, 

 thougli all hanging down in a wilted condition and showing unmistak- 

 ably that their functions had been suddenly arrested. 



I observed that orchard for some years afterwards. The second sum- 

 mer after this freezing the trees were badly affected with the yellows ; 

 the branches were covered with the small wiry shoots so characteristic 

 of this disease, which gradually extended, and, five years from the time 

 that the trees were so promising, the entire orchard had been rooted 

 out and the field set to another crop. 



It has always seemed to me that, if this orchard had been properly 

 pruned immediately after the freezing, it would have passed through 

 uninjured. If all the young shoots had been pruned back to hard and 

 solid wood, all probabilities of contamination from the diseased portions 

 of the shoots would have been prevented — and it is a commendable 

 l)ractice, for other reasons besides the above, to shorten in the points of 

 the strongest young growths of peach trees, this being one method of 

 thinning the crop of fruit. A heavy peach crop usually means much poor 

 fruit, for which there is no demand. There seems reason for the asser- 

 tion that, if the rule were strictly observed to promptly shorten back 

 t ho shoots of all peach trees which have been overtaken by a cutting 

 frost while such shoots are still in a growing condition and while the 

 leaves are unchanged from their green color, we should probably hear 

 less of the destruction of peach orchards by yellows. 



PEAR-TREE BLIGHT AND CRACKING OF PEARS. 



Forty years ago it was customary to ascribe all pear-tree blights and 

 cracking of the fruits, as well as most fruit diseases, to the absence of 

 eertain mineral matters in the soil. Wood ashes was a popular ]>re- 

 scri])tiou; a good dressing was considered a remedy; and where this 

 application failed to prove effective, it was then claimed that there was 

 a deficiency of iron in the soil, and a dressing of iron filings was pre- 

 scribed ; even hanging up among the branches of trees such articles as 

 lid horseshoes, old sickles, and scraps of iron was seriously recom- 



