January 19, 1893. ] 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
47 
in a stand of twelve bunches, with a proportionately greater number 
in larger classes. The great desideratum is to have the terms so 
clear that all exhibitors may know exactly what they must do to be 
within them. It ought to be as easy to avoid confusion in staging 
flowers as fruit. Fruit classes are made clear by being based on 
the word “ kinds,” with provisos specifying the number of varieties. 
It is seldom that confusion arises in either staging or judging in 
these classes, but uncertainty, not to say bewilderment, is much too 
common, both on the part of exhibitors and adjudicators, in con¬ 
nection with classes devoted to hardy flowers on account of the 
ambiguity or laxity of the terms employed in schedules. For pro¬ 
viding imposing displays the method of allotting space to trade 
growers for them to occupy in the manner they deem the most 
effective seldom fails. Under such conditions no doubt the finest 
collections of hardy cut flowers the world has seen have been 
displayed at exhibitions in this country. We are not cognisant of 
any widespread demand for a special society, as alluded to by 
Mr. Arnott.] 
CANKER ON FRUIT TREES, 
• 
I AM much obliged to Mr. Tonks for his lucid article on page 15, 
and wish to tell him that I intend, on a soil similar to that of which 
the analysis was given, to try the effect of special applications of 
potash, lime, phosphoric acid, and sulphate of iron on considerable 
breadths of ground. I hope to send the result to the Journal. In reply 
to “B. D. K.” (page 27), I can say that I have tried for several years 
the application of neat petroleum the ordinary crystal oil) well 
worked into the cankered places with a paint brush every spring. The 
wounds have not healed, but seem rather better than when it was first 
applied. Still it is evidently not a successful remedy by itself. It is, 
of course, a powerful insecticide, and after a trial of it it is difficult to 
see how the insect theory can be maintained as a cause of canker, for I 
cannot conceive of any insects frequenting the places for months after. 
It was put on in dry weather, and the dry bark would soak it up and 
hold the oil for a long time. It does not appear to have injured the 
trees in the slightest, though it has in many cases run down the bark 
below the wounds. 
If the fungus theory be correct, the wash should be a fungicide, not 
an insecticide, and similar treatment to that recommended by Mr. Abbey 
for Apple scab, applied at the right time should be sufficient. If the 
cure of canker depends upon the destruction of every cankered Apple 
tree in the locality that would furnish a supply of spores, it may be 
regarded as a hopeless case. My own opinion is that the root of the 
matter lies in the nutrition of the tree—i.e., at the roots, and that a 
tree, like a human being, will not take disease if in a thoroughly healthy 
condition, and that this may be arrived at by supplying all the con¬ 
stituents necessary to keep the tree in health, and 1 think that this would 
really be the treatment of “ the experienced practitioner,” rather than 
of “ the quack.” Possibly the removal of poisonous elements may be 
necessary, but the experience of Mr. Tonks proves that canker is curable, 
at any rate in his soil, by the application of what the tree needs to 
build up a healthy growth. 
Some sorts of trees appear to have a better constitution than others, 
or perhaps greater foraging powers, and a greater capacity to appropriate 
from the soil what is necessary for its existence, when it exists in 
limited quantity. Stocks probably influence in a similar way, and may 
account for variations in trees which are grafted with the same variety. 
On our soil it is not a question of which are the best sorts, but which 
are the healthiest sorts, then which are the best of these. Cobham for 
instance—that appears to do so well with many of your correspon¬ 
dents, and which I obtained from two reliable sources—cankers to death 
here, and I am just grubbing a number of trees which have been 
planted five years. It is also the same with a great many other sorts. 
On marking for destruction two trial trees of Gloria Mundi, which have 
also cankered to death, the Latin proverb. Sic transit gloria mtcndi, 
appeared most appropriate. Irish Peach is a sort which is very free 
from canker, but unfortunately grows and crops here very badly, and 
the fruit produced is almost worthless. 
On reading Mr, Abbey’s interesting article (page 27), I notice that 
he has misunderstood the purport of a sentence in my note. The reason 
I mentioned that Plums do well, while Apples and Pears cankered and 
Cherries gummed, was not because I was surprised at it, or expected 
them to be unhealthy, but to furnish the utmost data as to the soil in 
question ; for Mr. Abbey is doubtless aware that, from the healthy 
growth of certain plants and fruits, the presence of certain soil con¬ 
stituents may be inferred.— Walter Kruse. 
[We have other letters on this subject, but it will be best to defer 
their publication till Mr. Abbey’s comprehensive notes are inserted.] 
A Keview op Soils. 
Mr. Kruse states ; “ As the same varieties of Pears and Apples 
canker on one soil and do not do so on another, it seems a correct deduction 
that when they canker there is either something injurious in the soil 
or something lacking which they need.” Then follows an analysis of 
the soil in which Pear and Apple trees canker by the late Dr. Voelcker 
(Journal of Horticulture^ December 29ch, 1892, page 664). Mr. Kruse 
proceeds to draw conclusions from the analysis : ” It will be noticed 
that there is a large proportion of oxide of iron, as where there is more 
iron (how is this known ?) still in the soil in the same locality. Apples 
canker still more, and as it has been mentioned by some of your 
correspondents that Apples canker where there is much iron in 
the soil or subsoil, it would appear that excess of this is the cause of 
the canker.” 
I have shown in a previous article that canker is caused by a fungus, 
Nectria ditissima, and it goes without saying that iron will not produce 
any form of vegetable life, though it may and does form a fitting nidus 
or soil for the germination of the spores of fungi and the development 
of the fungal plants, also the perfection of their “ fruits.” But as there 
may be cankerous affections without fungal growths we may approach 
the subject broached by Mr. Kruse without preconception of ideas and 
conclusions founded on prejudice. 
Iron as a cause of canker in Apple and Pear trees. The soil (see 
analysis on the page above cited) does not contain “ a large pro¬ 
portion of oxide of iron,” that is 3-38 per cent, as compared with soils 
that produce the finest Apples. Mr. Kruse, however, does not confine 
his remarks to the analysis as an Apple soil, but considers it “ a good 
soil for fruit growing,” and as Kent is famed for its fruit, subjoined is 
an analysis of a soil found suitable for fruit production or Hops near 
Sittingbourne;— 
“"Organic matter and loss on heating 
... 507 
Oxide of iron . 
• • • • • • 
... 3-63 
Alumina . 
... 1-63 
Carbonate of lime. 
... 1-48 
Sulphate of lime. 
• • * • • • 
... 0-34 
Magnesia . 
• •• • * • 
... 0-42 
Potash . 
• • • • • • 
... 0'30 
Soda... 
... 001 
Phosphoric acid ... 
... 010 
Insoluble silicates and sand 
. 
... 84-14 
10000 
“"Containing nitrogen 
••• 
... 0-19 
Equal to ammonia. 
• • • • • • 
... 023 
— (Fream's “ Elements of AgriculUcre," page 21.') 
The “Leeds” soil analysis shows a higher per-centage of essential 
fruit-food—potash, 0'2l, phosphoric acid, 0’14—than the Sittingbourne ; 
also more alumina (272), carbonate of lime (2‘43), magnesia (0T6), 
and soda (0 06) ; but less iron (0 26), sulphate of lime 08), insoluble 
siliceous matter (127), organic matter, the store from which ammonia 
=nitrogen is manufactured (1’43). Mr. Kruse will note the fact that 
Sittingbourne is the home of the cultivated Cherries in this country, 
and have a world-wide celebrity, yet they gum there, and Apple and 
Pear trees canker. Nevertheless, Cherry trees are less subject to gum at 
Sittingbourne than in many other soils, because they are aided against 
it by the larger amount of siliceous matter and iron available for the 
strengthening of their epidermal tissues, whilst these are kept elastic by 
the free manufacture of ammonia (0’02 more in the Sittingbourne 
than in the Leeds analysis), = nitrogen (also O'02 better in the Sitting¬ 
bourne than the Leeds analysis, a mere matter of equivalents). 
If Mr. Kruse’s deductions are correct, Apple and Pear trees ought to 
canker more at Sittingbourne than at Leeds. There is more iron and 
siliceous matter ; in the Leeds soil the iron is sealed up in the 
alumina, and the two together eat up the ammonia, that is, there is not 
enough ammonia manufactured to ammoniate the iron and render it 
available as plant food. Why? 1, The organic matter is low, more 
“ muck ” is wanted, twenty-one tons of farmyard manure every third 
year at least, per acre, or its equivalent in “ artificials,” which I will 
allude to later. 2, The Leeds soil is retentive, far more so than the 
Sittingbourne, by reason of the alumina ; therefore, the air and rain 
cannot enter or pass through such soil and make its constituents as 
quickly available as in the other soil, which, however, has greater powers 
of manufacture chemically in the carbonate of lime, buc they cannot 
be exerted because the mechanical nature of the soil prevents it. That 
is the reason the Sittingbourne soil, chemically poorer, is better 
for fruit production and Hops than the richer Leeds staple. The 
carbonate of lime contributes to make the soil mechanically as well as 
chemically unable to manufacture plant food sufficiently fast for the 
requirements of the trees, and, though richer in constituents, it is poorer 
actually as regards output in fruit in the most saleable form than the 
Sittingbourne, in which the supplies are less but more available. 
In the Leeds soil the stores of food are locked up perhaps in a “ pan,” 
in that at Sittingbourne there are “ no bars” to hinder the trees from 
abstracting the amount of food essential to their health and f i uilf ilncss, 
because there is no pan such as must obtain in the Leeds soil from its 
composition—its calcareous nature. The carbonate of 1 me must 
dissolve and descend, and it will form a lime pan somewhere, generally 
at a moderate depth from the surface, too near in many cases for the 
long continuance in health of Cherry, Apple, and Pear trees—the former 
gumming and the latter cankering. The lime and the siliceous matter 
combine to form a concrete—mortar like, and the iron of the soil is 
washed into this pan, cakes and forms what is called an irony subsoil, 
and with the alumina holds ammonia as the smith does iron in a vice, 
so that it is practically useless to the trees (Cherry, Apple, and Pear), 
and the iron corrodes their roots and the tops canker. Plums succeed— 
no gum. The soil suits that fruit—the iron in a pan is held there to 
its especial benefit. Green Gage requires 6 04 per cent, in the whole 
fruit, and 7'45 per cent, in its skin, but the Cherry only needs S'74 per 
