260 STATE HORTICULTURAL SOCIETY. 



ever to do with yellows. This conclusion is based, in part, upon the follow- 

 ing facts : 



(1) lu the peach districts of Michigan severe frosts sometimes occur in 

 August and often in September, i. e., before the leaves have fallen; yet there 

 are localities where peach trees have been grown continuously for thirty 

 years, and where yellows has not yet appeared. 



(2) In the region of the great lakes early frosts have not been confined to 

 recent years, yet peach yellows did not appear there until quite recently, i. e., 

 in southwestern Michigan in 18GG; in nothern Ohio in 1878; in Ontario in 

 187G. 



(3) On the shore of Long Island sound, in the vicinity of New Haven, 

 Conn., peach yellows was very prevalent between 1831 and 1840; yet, during 

 the entire period of sixteen years, at Middletown, in the interior of the State 

 but not far removed, there was but one severe frost as early as September. 



(4) On the upper part of the Delaware and Chesapeake peninsula peach yel- 

 lows has appeared within the last three years in a great many young orchards, 

 often affecting hundreds of trees in a single orchard in one year. In 1887 and 

 in 1888 I saw it repeatedly in trees set only three or four years, and occasion- 

 ally instill younger trees, most of which were healthy in 1887. In connection 

 with these facts I made inquiries to determine (1) the exact dates at which 

 early frosts have occurred in recent years, (2) whether usually, or occasionally, 

 the peach is liable to lose its foliage prematurely, /. e., while its buds and 

 wood are immature. In 1887 and 1888 I supplemented these inquiries by ob- 

 eervations of my own. 



At Dover and Clayton weather records have been kept for a number of 

 years, and these show that there have been no severe early frosts, certainly 

 none that serve in the least to explain the sudden widespread devastation of 

 the orchards by yellows. Below is a synopsis from these records: 



At Still Pond, Md., the entries in the journal of Dr. W. S. Maxwell agree 

 substantially with the Dover and Clayton records, althougli thermometric read- 

 ings are not given. A daily record by Dr. Henry Kidgely, of Dover, also 

 agrees substantially with that of Mr. Jester, although not so complete. 



From these records it is clear that during the three years 1885 to 1887 there 

 were no frosts in August and none of any consequence in September. In 1885 

 the fiist severe frost was on October 10; in 188G it was on October 17; in 1887 on 

 October 15 ; in 1888 on October 10. 



The first point raised is whether the shoots of the season were in such an 

 immature condition at the time of these frosts as to be seriously injured by 

 loss of leaves, assuming for the sake of argument that the leaf function was 

 entirely suspended after these dates. The second point is whether the severest 

 injuries of this sort can develop peach yellows, or anything resembling it. 



In the autumn of 1887 I paitl particular atttention to the ripening of foliage 

 on deciduous trees, especially on the peach, and to the effects of the October 

 and November frosts Leaves in some orchards,, especially about Chestertown, 

 Md., began to fall in considerable quantities as early as August 25, but this 

 wae, I think, abnormally early. 



At Dover, in the McDaniel orchard by September 27 from one third to two- 

 thirds of the leaves on all the lower branches had already fallen, and those 

 remaining on these branches (except the terminal ones) detached very readily 

 wlien the shoots were seized at the base ajid drawn gently through the half- 

 closed hand, thus showing that though still green their work was very nearly 

 completed. Some of the smaller branches had already lost all their leaves. 



