250 STATE HORTICULTURAL SOCIETY. 



to this disease. At this stage the most careless observer is aware that some- 

 thing is wrong with the orchard. The trees have a most miserable, sickly,, 

 languishing appearance. Some curling and inrolling of the leaves is un- 

 doubtedly due to mites or other leaf insects, but I could not satisfy 

 myself that all of it was so caused. It should also be stated that the leaves 

 on the diseased, secondary or summer shoots do not ordinarily show this roll- 

 ing and curling. Frequently there are brown or red spots upon the foliage, 

 but this is not a constant symptom and appears to be due to a leaf fungus 

 {Cercospora), which finds in the diseased leaves its must favorable condition 

 for growth. 



THIRD AND LATER YEARS. 



The diseased tree rarely dies the second year of attack and rarely lives 

 beyond the fourth or fifth year. It is generally worthless after the second 

 year, i. c, after all the branches have once borne the premature peaches ; 

 sometimes it becomes entirely diseased and worthless the first year of attack. 

 Whatever may be thought of remedies, it is certain that left to itself the dis- 

 eased tiec invariably dies. It is not more likely to recover than is a con- 

 sumptive animal. I have heard it said that such trees sometimes recover, 

 but none under my own observation have done so, nor can find satisfactory 

 evidence of any such recovery. 



The symptoms of these later years are those previously mentioned, to 

 which may be added some additional ones due apparently to an increasing 

 lack of vitality. One of these is the death of large limbs and, finally, of the 

 entire tree. Sometimes as early as the second year, and quite often the third 

 or fourth year, the only symptoms of life exhibited by the tree are a few 

 very feeble, dwarfish, broom-like tufts of branches, developed from obscure 

 buds, here and there upon the otherwise naked limbs. These branches are 

 clothed with very depauperate leaves of a greenish-yellow or reddish-brown. 



Some additional minor symptoms attracted my attention, but not being 

 certain that they are constant I present them here as suggestions rather than 

 final conclusions. 



The diseased shoots appear very brittle. I first noticed this in trying to 

 make some withes, and alterwards found it nearly or quite constant. This 

 recalls a statement made by Noyes Darling that diseased branches lose their 

 elasticity and sway in the wind with " a stiff, jerking motion." I did not 

 meet this statement until my field work for 1887 was comjJeted, but, in 

 connection with the brittleness, I am inclined to give some weight to it, 

 particularly as JS'oyts Darling seems to me to have been the most acute 

 observer and the most logical thinker who has ever written upon peach 

 yellows. 



In diseased limbs I also found that the cambium-cylinder was active very 

 late in the fall, as might be expected from the prolonged growth o( leaves 

 and shoots already mentioned. This activity of the cambium continued 

 long after it had ceased upon the neighboring healthy trees. This was indi- 

 cated by the ease with which the bark could be peeled. In Kent county, 

 Del., in all cases, the bark of healthy trees stuck tightly and could not be 

 peeled at all after the last of August. From diseased branches in the same 

 orchards long strips of bark could readily be separated as late as September 

 20, leaving exposed the smooth, moist surface of the wood. 



