October 26, 1893. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
878 
is seldom we have too many of this, as it ripens slowly ; and its season is 
easily extended by a little care in gathering, and by keeping the later 
fruit cool. Moreover, no Pear sells better, as it holds a high character 
in the market.” The latter sentence is obviously in conflict with Mr. 
Molyneux’s experience, and it would be interesting to have the opinion 
of others on this point. 
Presumably the same correspondent, “ B.,” deals with the question at 
ssue on page 309, and in the main agrees with my suggestion, as will, I 
venture to say, many northern gardeners. In the same issue “ R. P. R.,” 
writing from the neighbourhood of Iiiverpool, points out clearly the 
advant..ge of Pears over Peaches on walls ; and while that is but a single 
case in point, it will add weight to the discussion. Mr. Molyneux I 
believe has, like myself, had some gardening experience north of the 
Trent, and he wilt perhaps say whether he has grown Peaches, or seen 
them cultivated, on walls outdoors as well in the northern counties as 
he can manage to produce them in Hampshire. “ Y. B. A. Z.” and 
“ W. S.,” on page 309, are in favour of Peaches, as will doubtless be 
other correspondents who reside in such favoured counties as Somerset 
and Wiltshire, but even these may have found, and doubtless will find, 
that all seasons are not so conducive to successful open-air Peach culture 
as has been 1893. 
Another case in support of my contention might be mentioned. In 
the Journal of Horticulture last week (page 353) a paper which Mr. 
G. Bunyard of Maidstone read before the Horticultural Club is printed. 
In this Mr. Bunyard refers to certain varieties of Pears as being excep¬ 
tionally fine this season, and remarks, The palpable lesson here is that 
we ought to place all such good but ‘ difficult-to-grow ’ sorts on south or 
south-west walls, where they would in many cases do better than Peaches 
and Nectarines.” When we find such an authority on fruit culture, and 
a resident in “ sunny ” Kent, advocating the culture of choice Pears on 
south walls in preference to Peaches it is not at all surprising that 
northerners have found it to their advantage to do likewise.—C. 
“ R. P. R.” (page 309), in his closing remark anent the sale of 
Williams’ Bon Chretien and Pitmaston Duchess Pears in the leading 
Liverpool fruiterers’ shops, is not quite clear on the point. Does he 
mean that the fruiterer has been receiving 3d. and 6d. each for these 
Pears? I take it that is what is meant; but how about the grower? 
The prices quoted do not give any information how that individual 
fared. He is the person whom the subject of “ Pears versus Peaches ” 
most concerns. If the prices quoted are those received by the grower, 
then there is just reason to say that Pears are more worthy of attention 
from a market point of view than Peaches. I saw but a few weeks 
since some fine Duchesse d’Angouldme Pears being sold for Id. each. 
This was what the grower received, and from one of the best fruiterers 
on the south coast. What the latter sold them at is another question. 
My business is with the grower, and I suspect this individual was solely 
in the mind of “ C.” (page 259) when he started this interesting con¬ 
troversy, 
I, like “ Y. B. A. Z.” (page 309), regard Beurre Diel as worthless as 
a dessert Pear. Even in the most favoured soil for Pear culture it is 
inferior to such varieties as Doyennh du Comice or Marie Louise, 
but in soil that is unsuited to its constitution it is not worth the room it 
occupies. 
In my opinion “ blister ” on the Peach leaves is caused mainly, if 
not quite, by east winds. Some two or three years since we had no east 
winds one season at the critical period, and we experienced little or no 
“ blister.” My plan when disbudding trees addicted to “ blistering” is 
to leave an extra number of shoots for a few weeks until the trees have 
passed that stage. We can then afford to remove entirely the worst of 
the “blistered” shoots. In cases where the leaves only are affected, 
these are picked off directly they are injured. Upon the advent of 
more genial weather the shoots grow out of the “ blister.” The practice 
of leaving an extra number of shoots at disbudding time is decidedly 
advantageous, and one that cultivators troubled with blister would do 
well to adopt.—E. Molyneux. 
Peach-leaf Blister. 
I HAVE pleasure in responding to the Invitation of “ Y. B. A. Z.” 
(page 309) to give my views on the cause of Peach-leaf blister, prompted, 
as he evidently is, by a desire to arrive at the truth. “ What is Peach 
blister?” asks Mr. Edward Luckhurst in the Journal of Horticulture 
of June 22nd, 1870, page 181, then proceeds to answer his own question 
as follows :—“ It is a disease affecting the foliage only when young and 
tender, appearing in the form of blotches or blisters irregular in form and 
size, being sometimes as small as a pea, and occasionally spreading over 
an entire leaf. The affected part, having a pale sickly appearance, 
becomes much thicker in substance than the healthy part, and rises into 
a convex form precisely similar to other blisters. It is distinct from all 
other forms of blight, and cannot be mistaken.” Mr. Luckhurst next 
asks, “What is the cause of Peach blister?” and again answers, “ It is 
caused by the exposure of the expanding foliage to the influence of 
frost or cold cutting winds.” Evidence in proof of this conclusion is 
then given. 1, Trees on a west wall had “ fine foliage, perfectly clear, 
and quite free from blister or blemish of any kind,” 2, Trees against 
an outer south wall, “ along which the cold east wind swept unchecked,” 
had the leaves much blistered. 3, Trees on a south inner wall had the 
leaves quite sound near the east end, “ but further on where the trees 
were more exposed they were affected precisely in proportion to the 
extent of such exposure ”—that is, to the cold east wind. 
Whether “Y. B. A. Z.” had Mr. Luckhurst’s article in mind at the 
time of writing on page 309, matters little ; but I consider it important 
that all evidence bearing on the subject be given due consideration. 
Therefore a few brief notes on Mr, Luckhurst’s article may be made 
with profit. From a cultural point of view there is nothing in the 
article referred to to which exception can be taken. Mr. Luckhurst 
tells us to “ watch the development of an organ [foliage] upon the 
condition of which everything depends—the crop, the growth, the very 
existence of the tree itself, to cherish it by every means in our power, to 
cleanse it from insects with a prompt and ready hand, and to screen it 
from frost and cold cutting winds.” That is good cultural advice, but 
all the same Mr. W. G. Smith had proved that fungus was the cause of 
Peach leaf blister, and exploded the opinion that had prevailed up to 
that time—namely, “the blistering being caused by spring frosty 
rupturing the sap vessels and the fungus living upon the extravasated 
sap.” Mr. Smith’s explanation and illustration of Peach blister with 
accompanying fungus (Ascomyces deformans) will be found in the 
Journal of Horticulture ot July 8th, 1875, and he, following De Bary 
and Berkeley, practically settled the question on a sound basis. 
1 think it necessary to make the foregoing observations in justice 
alike to Mr, Smith and Mr, Luckhurst, for it is not right that we should 
profit by the teachings of others without giving expression of our in¬ 
debtedness. This gives me an opportunity of saying that the little I know 
about fungi and the diseases caused by this class of parasites is mainly 
due to studying the works of the late Rev. M, J. Berkeley, Dr. Cooke, 
and Mr. W. G. Smith. Information has also been derived from articles 
appearing from time to time in the Journal of Horticulture and in the 
Gardeners' Chronicle. Most of the subjects treated by the specialists I 
have endeavoured to study on the plants the parasites infest, and pro- 
duce disease on or in, and the result in all cases has been a verification 
of their teaching, and conclusive proof of the desirability of acquiring 
scientific knowledge as well as cultural practice. 
Mr. Smith has given decisive proof that all the exposure of the 
expanding foliage of the Peach to the influence of frost or cold cutting 
winds was capable of producing a favourable medium for the growth of 
the fungus. This may seem to confirm Mr. Luckhurst’s contention that 
the fungus was consequential and not initiatory of the disease. But it 
is at this point where the great gulf exists between cultural conjecture 
and scientific fact. Who has ever seen the young growths of any tree 
blistered and distorted without a cause? The east wind never produces 
anything beyond a stunted and crippled growth. There is no blister 
without its cause, the growth of the mycelium of the fungus within 
the leaf and shoot tissues ; no curled leaves and distorted growths without 
the causing parasites or insect pests. While approving of the cultural 
advice given by successful Peach growers I have to say that the Peach 
tree leaf blister is not caused by cold or east winds, but by a fungus. 
This enemy is not confined to this country, but is found on Peach trees 
on the continent under the name of Esoascus deformans, and in America 
under that of Taphrina deformans. The continental trees against walls 
receive similar protection to that given in this country ; in America the 
trees are grown as low standards, and have no protection whatever. In 
all regions of the earth where the Peach is grown it is subject to attack 
by the parasite, because the leaves afford it its peculiar food. Surely 
that is simple enough to be comprehended. The fungus is a plant, 
endowed with the power of growth and reproduction. It springs into 
existence from a spore. There is nothing mythical about it. True it 
belongs to a very lowly group of the Ascomycetes family of fungi, but it 
has great power in producing distortion or deformities in the leaves of 
Peaches and other trees. We can see the parasite in all the stages of 
growth as plainly revealed by the microscope. We cannot see the east 
wind ; it is said that pigs can, but as they cannot tell us what there is 
in it, we will believe what we see—namely, the fungus growing in the 
leaves of Peach trees and the blistering that follows. 
The Peach leaf blister fungus, Exoascus (Ascomyces, Taphrina) 
deformans, makes its presence manifest by the red blisters on the leaves. 
These are due to the previous action of the mycelium within the leaf 
tissues, enlarging and multiplying the cells, giving rise to the thickening 
and swollen condition of the leaves. The first indication, however, of an 
attack by the fungus is an abnormal growth, a thickening and deepening 
of colour in the leaves. There is no pale sickly hue such as results from 
exposure to cold or the presence of aphides, for sickly leaves are of no 
use to the fungus, as it lives upon the chlorophyll. This the mycelium 
destroys, and red colouring matter takes its place, as seen in the 
blisters. Ultimately, the mycelium or outgrowths from it burst through 
the cuticle or skin of the leaf, and appears as a fine pale bloom, visible 
chiefly on the lower surface. This consists of a stratum of fine 
threads, from which spring innumerable erect, slender flask-shaped 
bodies (asci), each supported on a shorter cell. Each ascus contains 
eight minute oblong spores ; these, escaping by an orifice at the apex, go 
forth to reproduce the fungus. In addition to asci, other necklace-like 
growths spring from the threads, and consist of simple cells or spores, 
which are considered by Mr, Smith to be capable of reproducing the 
fungus. Excellent illustrations of the attack on the leaves and of the 
fungus will be found in the Journal of Horticulture, vol, xxviii., new 
series, page 31, by Mr. W, G, Smith. 
The leaves covered or attacked with Exoascus deformans wither an I 
fall off prematurely. The period of attack is confined to the spring or 
early summer, for when the weather becomes warm and settled the 
growths start freely and the leaves are not attacked by Exoascus 
deformans. This has led to the erroneous conclusion that the fungus 
spores are only able to act on tissues impaired by cold weather. Frost 
