July 26, 1894. 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
7;’, 
^ - ■ 
CHLOROSIS OR YELLOWS 
IN PEACH TKEES AND TOMATOES. 
-X- 
T he late Mr. R. Thompson says;—“The yellows [in Peach 
trees] is a disease little heard of, except in America, where it 
destroys whole orchards in a few years. It invariably manifests 
itself in trees growing on the Peach stock, and consequently in 
order to avoid it they should be worked on the Plum or on the 
Almond ”—(“ Gardener’s Assistant,” first edition, 1859, page 556). 
This was written subsequent to the then late Mr. Downing’s 
statement in his “ Fruits and Fruit Trees of America, “ that this 
serious malady [the yellows] seems to belong exclusively to this 
country, and to attack only the Peach tree. Although it has been 
the greatest enemy of the Peach planter for the last thirty years 
[since 1830], rendering the life of the tree uncertain, and frequently 
spreading over and destroying the orchards of whole districts ; 
still little is known of its nature, and nothing with certainty of its 
causes. Many slight observers have confounded it with the effects 
of the Peach-borer, but all persons who have carefully examined it 
know that the two are totally distinct. Trees may frequently be 
attacked by both the yellows and the borer, but hundreds die of 
the yellows when the most minute inspection of the roots and 
branches can discover no insect or visible cause.” 
Mr. Thompson’s statement that yellows “ invariably manifests 
itself in trees growing on the Peach stock ” has received no con¬ 
firmation during the last thirty years. On the Continent chlorosis 
affects Peach trees both on the Almond and Plum stock, and the 
disease, though not common, is not unknown in this country, 
where Peach trees are almost exclusively worked on Plum stocks. 
What is yellows ? “ The first symptom in bearing trees is 
usually the premature ripening of the fruit. This fruit contains 
definite small red spots which extend to the pit. The next stage is 
indicated by very slender shoots, which branch the first year, and 
which start in clumps from the old limbs, bearing narrow and small 
yellow leaves. Later the entire foliage becomes smaller and 
yellow. In three or four years the tree dies. The disease spreads 
from tree to tree. It attacks trees of any age. Known at present 
only in regions east of the Mississippi, more particularly in the 
North-Eastern States. Peculiar to America, so far as known.”— 
(Mr. L. H. Bailey). This (American) description and view of 
yellows differ somewhat from what I have seen of it in this 
country, where the disease manifests itself in the early stages of 
growth, the leaves assuming a pale green hue, becoming decidedly 
yellow when they are fully developed, then they have a pretty 
appearance through the veins, ribs, and midrib of each leaf being 
of a darker greenish colour, similar to but less decisive than in 
Golden-leaved Elder. This is mainly due to the greater density of 
those parts as compared with the thinner tissue of the leaf, for a 
minute section through a midrib is quite pale in colour under the 
microscope, and absolutely destitute of chlorophyll (green colouring 
matter of leaves). After a time the leaves fall, sometimes quite 
suddenly, especially if the house be fumigated ; in other cases they 
remain until nearly the usual period of their falling naturally, and 
assume a purplish tint here and there on the yellow ground, not 
unlike the ripening tints of Gros Colman Vine leaves. In either 
instance the shoot is marked by sterility, the first not forming any 
blossom buds and few puny wood buds, and the latter has a number 
of blossom buds with a terminal growth bud and several smaller 
ones at the base. The shoot losing its leaves early generally fails 
No. 735.—VoL. XXIX., Third Series. 
to produce any growth whatever the following year, but a tuft of 
young shoots spring from below on the two-years or older wood, 
and these are lean, long-jointed, and push laterals from most every 
joint. These shoots also are sterile so far as fruit is concerned, 
but they may live on, producing nothing but spasmodic growths 
and pale siokly-looking foliage. They, however, collapse suddenly 
in some instances, and not unfrequently the whole branch dies 
after the stoning of the fruit is completed without, as the saying is, 
cause or reason. This is a very serious matter, first one branch and 
then another going off until the tree is a mere skeleton, dying by 
inches, feet, yards. If we examine a collapsed growth or branch, 
there is no trace whatever of disease caused by micro-organisms 
fungi, or insects. 
The affected shoots retaining their leaves in the year of appa¬ 
rent chlorosis cast every blossom bud in the next, and the wood 
buds only push a few tiny sickly leaves, and then die. Below the 
point of collapse a number of shoots spring from the older wood, 
latent buds even on the oldest limbs being called into activity. These 
mostly are gross, and start nearly every bud in the axils of the 
leaves, these (laterals) having pale green or yellowish leaves, large, 
but thin in texture. Such may live for a time—even years— yet 
sooner or later these erratic and gross growths fall away, die 
suddenly, sometimes before and at others after the fruit has 
ripened, the leaves falling prematurely, and the branch perishing. 
Indeed, the tree affected with yellows succumbs gradually, gets 
smaller by degrees till the end comes. 
The foregoing are the two phases under which I have observed 
yellows in Peach and Nectarine trees. It seems more decisive in 
standard trees, those with 3 feet or longer stems, which are budded 
at the heights required to reach the trellis or form the head at a 
given point, than in dwarf trees or those employed for walls, or 
cordons, or as bushes or pyramids in pots. Rider trees succumb 
sooner than dwarfs trained to walls. This implies stock or stem 
influence, and might be usefully discussed, not only as regards the 
Peach on Plum stocks, but also the Pear on the Quince. It is, 
however, only a Mr. T. F. Rivers or a nurseryman of life ex¬ 
perience that can handle the subject in a thoroughly practical and 
useful manner, therefore I pass this question of life and death 
interest to the cultivator with extreme reluctance and a vearnin" 
w O 
for information on this important matter—that of stocks on which 
the trees we cultivate are worked. In my experience I found a 
great difference in the trees from the stocks on which they were 
budded. On a certain stock Grosse Mignonne Peach is tender, 
very liable to mildew, and altogether unsatisfactory on walls, but 
on another stock it is the best Peach in cultivation for size, 
colour, and quality, remarkably healthy, and free from mildew and 
other kindred diseases. This, not in different soils and locations, 
but under an identity of conditions, therefore there was no question 
as to its being a case of stocks. I allude to Grosse Mignonne 
Peach because it is one of the oldest and the parent of varieties 
with hardier constitutions, though some, as Belle Beauce, are 
equally susceptible to injury from climatic and soil influences. 
Now Grosse Mignonne is a yellow fleshed Peach ; the yellow 
fleshed Peaches are tenderer—if I may be allowed the expression— 
in the highest evolution. Such is the case everywhere, in France,, 
in this country, and in America. They are the most difficult to 
cultivate, the best when had at their primest. This is an outcome 
of cultivation—call it evolution or whatever we may please. It 
practically implies greater care, more favourable conditions, and a 
stricter and well defined regimen. This does not necessarily narrow 
but broaden effort—seedlings from Grosse Mignonne are hardier 
than it, and these are less prone to yellows, especially the wildlings 
in the virgin soils of Utah, so esteemed in California as stocks. 
Significantly also the Almond, from which Peaches, according to 
Darwin and Pliny, have been evolved, is esteemed in France as a 
stock, especially for light soils and dry climates. This being so^ 
it follows that health is found in the species or variety nearest 
No. 2391.~Vol. XCI., Old Series. 
