APPLE DISEASES 



485 



the circulation of sap and tlie food sub- 

 stances. This lack of circulation and lack 

 of air, is caused by the packing or run- 

 ning together of the soil particles in irri- 

 gation, forming a tough, waxy substance 

 through which water does not penetrate, 

 nor the air circulate." 



Some of the letters and bulletins from 

 which these extracts were taken are near- 

 ly two years old, and may not fully rep- 

 resent the views of the writers and auth- 

 ors at the present time, but I have seen 

 nothing from their pens to the contrary, 

 and believing that they express truth, I 

 have quoted from them in support of my 

 own views. 



"Rosette occurs in the pecan and the 

 following note as to its cause and distri- 

 bution from M. B. Waite, of the Depart- 

 ment of Agriculture, is appended. 



"The pecan rosette occurs in humid re- 

 gions. I have seen it most abundantly in 

 South Carolina, Florida and Alabama. I 

 am under the impression also that it oc- 

 curs in Texas, but have not any definite 

 reports by which I can give you its dis- 

 tribution in that state positively. The 

 points in which I have observed it in 

 South Carolina, Florida, Georgia and Ala- 

 bama are not only in the humid Eastern 

 states, but in distinctly moist sections 

 near the Atlantic seaboard and the Gulf 

 coast. The pecan grows with great lux- 

 uriance in the bottom lands along the 

 Mississippi and its tributaries in Louis- 

 iana, but I do not recall having seen the 

 rosette on these bottom land trees. I 

 have not, however, personally hunted for 

 the disease in this section. 



"Doubtless you know that the pecan 

 rosette is a little known disease. It is 

 under investigation by the Department 

 and is supposed to be a physiological 

 trouble induced by soil conditions. We 

 are not prepared, however, to say just 

 what these conditions are. 



"Now, as to the apple rosette, it does 

 occur rarely in the Eastern states. It 

 has occurred at Winchester, Va., during 

 the years 1911 and 1912, on a few trees of 

 York Imperial in a young apple orchard 

 five or six years old and just beginning to 

 bear some fruit. It was also found in 



1911 in Loudoun county, Va., east of the 

 Blue Ridge and some 30 miles distant 

 from Winchester. It is a notable fact, 

 however, that this rosette should appear 

 after two or three very dry seasons. In 

 the district named, the latter part of the 

 season of 1909 and the seasons of 1910 and 

 1911 were notably dry, particularly the 

 summers. Springs and wells, as well as 

 streams, were lower than they had been 

 for many years. Fairly good crops were 

 produced, except the hay crop of 1911, due 

 to drought in June, but there is no doubt 

 about the general deficiency of subsoil 

 moisture during this period. 



"It should be stated that apple rosette 

 is so rare in the East as to be only of 

 scientific interest. It is not abundant 

 enough to be of any serious economic im- 

 portance east of Nebraska and Kansas. 

 From those states westward it is one of 

 the most important orchard diseases. The 

 disease called Chlorosis, which we have 

 considered to be somewhat related to ro- 

 sette and which intergrades with it in the 

 West, behaves in the same way. This 

 physiological trouble is an important dis- 

 ease from the Missouri river westward, 

 but is rather scarce all over the humid 

 states. It occurs, however, much more 

 frequently than the rosette, and I have 

 observed it in several states, notably New 

 York, Pennsylvania, Maryland, West Vir- 

 ginia and Virginia." 



Geanville Lowther 



Rust 



Oymnosporangium spp. 



Apple rust is a widely distributed dis- 

 ease, and in some sections is quite in- 

 jurious. It is of common occurrence in 

 Eastern states and, while not one of the 

 most serious apple troubles, it often does 

 considerable damage. It sometimes at- 

 tacks the fruit, but its effects are usually 

 confined to the foliage. Here it causes 

 yellowish spots which usually become 

 somewhat elevated in the center and in 

 which are produced numerous spores. The 

 spots usually appear on the leaves in 

 June. The spores from these spots are 

 borne by the wind and attack the twigs 

 of Junipers, causing morbid growths or 

 swellings. One of the most characteristic 



