CUnLED LEAF ON THE PEACH TREE, 



3'ear by year, both before and since the advent of the curled leaf, have stood the winter 

 well, and have been uniformly covered with flowers; and yet they have suffered peculiar- 

 ly from the ravages of the curled leaf for two j^ears past. The '" Teton de Venus" also, 

 though its fruit buds have not stood the winter well, is a very strong grower, and drops 

 its leaves in good suason in autumn, yet it has been almost ruined by the curled leaf. 



3. In all cases where the center leaves of the bud when it lirst opened, exhibited the 

 cu)l, the shoot beneath never elongated at all, or not more than an inch or two, and then 

 the whole withered and died under the curl, 



4. In those cases where thi center of the bud did not exhibit the curl, the shoot elon- 

 gated regularly, although as it grew there might be curled leaves at the base, and along 

 the sides of it. Such branches flourished, being a little dwarfed until they cast ofl" the 

 diseased leaves. 



5. In a kwf cases the points of the shoots, and at other times the side and base leaves, 

 were found diseased with the curl in mid-summer. In all such cases there was a clear 

 connection between these diseased manifestations and the state of the weather. 



6. Each one of my tnes, (I have five or six hundred,) so far as I have observed, haa a 

 definite proportional liability to thi curled leaf; that is, the tree that suffered severely, 

 slightly, or not at all last year, suffered similarly this year. 



7. I think also, (althougli my attention has not been so definitely directed to that point 

 as to some others,) that those trees that are most liable to be heated in a calm warm day, 

 and subsequently to be severely chilled b3-cold wind, are also most liable to be affected by 

 curl. All this is consistent with another fact, that half hardy trees, of which the 

 peach is one, do undoubtedly succeed best when their position, on the whole, is a cool one, 

 and as little exposed as possible to clianges of weather. 



8. So also, sickly trees are found in succeeding years, to be particularly exposed to the 

 curl. This results obviously from the foct that its whole vigor is reduced. 



9. When first beginning to curl, the whole leaf, but particularly the foot stalks, ribs, 

 and glands, exhibit a high degree of transparency, and usually a redness. This, on ex- 

 amination with the microscope, exhibits no insect, egg, puncture, or other irregularity, 

 often not even the curl, in the very young state of the leaf. Its growth, also, for a few 

 days, seems nominally rapid. What strikes the observer is the transparency which seems 

 to reveal almost the whole interior circulation of the leaf; the wax-like smoothness of the 

 surface of the young leaves; the reddish tinge; the early disposition to cuil. This last 

 disposition is sometimes seen in the tendency of the two opposite halves of the leaf to ad- 

 here to each other, and at others, in the edges of the leaf to corrugate, just as in that form 

 of the potato disease that is caused by chills at a later period in the summer. The pro- 

 gressive enlargement of the leaf, its endless contortions, its changes to various colors, but 

 especially the studding of its surface loith delicate velvety blotches, of a most beautiful 

 texture and coloring, are all very noticeable facts. These velvety blotches are undoubted- 

 ly a fungus formation, not however, I think, of a parasitic character. Soon these pro- 

 gressive manifestations are finished, as the leaf blackens, dies and falls. 



May we not derive some illustration of the mode of atmospheric influence in this case, 

 from the condition of leaves generally, in autumn. Then, when the light and heat are no 

 longer such as to satisfy the normal requirements of vegetation, when especially the down- 

 ward progress of vegetation has been hastened by severe and sudden frost, we see the same 

 discoloration and death. In the autumn, however, the deposition of woody matter in 

 ivf is complete. Hence, when those atmospheric changes come that paralyze the cir 

 ulation, and give to chemical law the mastery over vital energies, and the sap becomes 



