284 QUARTERLY JOURNAL. 



crops that follow, there are many circumstances that I have noticed, 

 that inclines my opinion in that direction. In England, where 

 the peach tree is subjected to artificial management, rendered ne- 

 cessary by the humidity and deficiency of solar heat in that cli- 

 mate, to bring the fruit to perfection, either on walls or under 

 glass, the "yellows" are not known. It is true, there are many 

 insects, parasites, fungi, and other epidemics peculiar to this 

 country, not known in Europe, and vice versa, that are very de- 

 structive to the cultivation of fruits and fruit trees. Consequently, 

 this circumstance of itself is no proof. But the fact that in Eng- 

 land, where peach trees are subjected to a regular routine of treat- 

 ment, (of which I shall have a word or two to say in conclusion) 

 the " yellows" are unknown, caused me in the first instance to look 

 in that direction ; and, although the instances afforded me for ob- 

 servation, and experiment, are but few, yet so far they bear out 

 the theory which I have ventured to advance, that much of what 

 is called yellows, is caused by exhaustion, and the entire neglect 

 of a systematic routine of pruning, trimming the superabundant 

 fruit crops, &c. 



In 1839, there were among other fruit trees at this place (the 

 establishment of A. J. Downing, & Co.) some old peach trees in 

 bearing, part of which had the " yellows," and nearly all of which, 

 (only two or three being left) have since disappeared, in the usual 

 manner that trees do having the " yellows," or getting the disease 

 from whatever cause. In the spring of that year, there were some 

 young trees planted out, as standard trees, that have been pruned 

 regularly every spring since ; they have borne fine fruit for the 

 last two years, the vigor of the trees at the same time being unim- 

 paired, and show no symptoms of the yellows as yet. In the 

 spring of 1840 and 1841, some trees were planted out for training 

 in the manner of wall-trees, some of which were sorts known to 

 be diseased, and consequently have since died ,• t^e others, thad 

 were of thrifty stock, have grown well, and have been pruned and 

 trained in the usual manner as practised on wall-trees in Great 

 Britain, &c. Some of them bore magnificent fruit last season, and 

 are in a most luxuriant and healthy state. Again, peach trees 

 with entire leaves, which are sorts not subject to mildew, are gene- 

 rally the greatest bearers, and generally most affected by the "yel- 

 lows j" while, on the contrary, peach trees with serrated leaves 



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