‘SeDtemb r 27, 1888. J 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER . 
281 
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I 
GUMMING IN FRUIT TREES, j 
+ 
C ONTINUING this subject from page 258 last week, it may be noted 
that trees worked on hardier stocks have gum almost exclusively 
in the scion, the part below the junction of stock and scion being 
free from disease. This applies equally to standard or dwarf 
frees— i.e., long stems or short stems of the stock ; indeed the stock 
in most instances remains healthy after the tree above the junction 
has all but succumbed to gum. What is this evidence of ? That 
■the stock is hardy and healthy. If so, it is conclusive of the care 
■exercised to procure stocks that will produce trees of the most 
desirable form in the least time. It is healthy, and in every way 
.suitable as a stock for the purpose desired by a rearer of fruit 
trees for sale. That may be, but what of the bud ? Is equal care 
taken that it be of a healthy kind ? There is no, and has been no 
^um on the tree from whence the bud is taken. If so, my objection 
•ceases ; but if the bud is taken from a tree that has been (if not 
then) affected with gum, it is, to say the least, tainted, and i3 pre¬ 
disposed and liable to exhibit the disease from inherent tendency 
sooner or later ; indeed it only awaits certain climatic or cultural 
-conditions to obtain in order to induce disease. The trees may not 
have gum so long as the effort is directed towards the production of 
wood, and the parts formed are annually cut away to an eye or two 
at the base on the hard pithless ripe wood. What if the trees are 
not transplanted so as to check the undue vigour that must result 
from the hard winter pruning ? Gumming is certain, and not less so 
if the growths are retained instead of being lopped. It is when the 
-vital forces are, or should be, directed to reproduction, that gum¬ 
ming appears. It may be on the current or the preceding year’s 
wood, a present or a consequence of plethora, a deficiency of the 
power of elaboration and assimilation, resulting through the want 
■of leafage to evaporate, or restraint of evaporation from deficiency 
■of light and air, combined with excess of moisture, or directly caused 
by large reductions of foliage at a time as in disbudding, or allow¬ 
ing the growth to become crowded and then removing it by armfuls. 
But not to anticipate, let us keep to the young tree. It is in the 
nursery rows—a stout short-jointed tree, without a tendency to 
throw laterals from the shoots at some little distance from its 
origin, going its full length without lateral formation. It is not 
unduly strong—in no sense gross—its wood is firm, and its buds are 
prominent in the axils of the tree. It is a safe tree. Mark it. 
Reject the gross tree, and the weakly ; the former is already 
plethoric, and the other is sure to become so when planted in soil 
•such as is provided in culture. Of course there is a remedy ; the 
•gross tree may be lifted and cut hard back, and the weakly not 
given too rich soil, so as not to cause it to pass all at once from 
poverty to luxury. There is nothing, however, like the healthy 
tree to begin with, and if there is asiy trace of gum, or dead patches 
■on the bark, the stock is unhealthy and only fit for burning. 
How does the tendency of a tree to disease come ? Budding on 
-a stock fully a hundred times its strength, the aliment of a hundred 
■parts being forced into it by the heading down process, it makes in 
a season as much growth as the stock required to effect on Nature s 
plan in three to six. It is the way to get a strong tree of a desired 
kind in little time. No question arises as to its being a ready 
means of transforming a wilding into a useful tree, but is it not 
•conducive to disease ? If the stock when worked be gross it will 
transmit that grossness to the bud or scion, and I shall submit that 
No. 431.— Vol. XVII., Third Series. 
grossness is the predisposing cause of gumming, induced in the 
maiden tree by the luxuriance of the stock. The stock may be 
hardy, which is suTcient to account for its immunity from gumming 
and the obstruction to the descending current by the junction 
tends to increased vigour of scion, so that it stores up more food 
than it otherwise would, and as a result earlier puberty ensues than 
would be the case were the stock allowed to follow Nature. 
The gross miiden tree is not so certain of forming fruitful 
parts as the moderately vigorous ; the former has larger sip vessels, 
and as such is more liable to suffer from vicissitudes of climate, 
making a late growth, and the wood is not nearly so well ripened. 
It is liable to rupture of the sip vessels through their containing 
watery unassimilated sap in severe weather, showing evidence of 
injury before it is headed. It is plethoric as a maiden and never 
forms a healthy tree, for if lifted as a maiden the plethoric part— 
i.e., the few inches of the first year’s growth remain, and it is on 
that part that gumming appears in otherwise healthy trees, and to 
which they ultimately succumb. This is very comm in. with 
Cherries—viz., gumming is most prevalent on the part imme lately 
above the junction of stock and scion ; it is common enough in 
Peaches, Apricots, and Plums, whole branches dying off from 
gumming at the point of origination, the result of error in the 
early stages of its existence. The stock being a means of accli¬ 
matising certain fruits it does not necessarily follow that plethora 
is certain to result in climates unfavourable to them, though we 
find trees outdoors are more subject to gum than those grown under 
glass, indeed we have evidence that trees against walls very much 
injured by gum were less so when enclosed in a glass case, and 
still further free from the malady when artificial heat was em¬ 
ployed, as immunity or otherwise from this disease depends on the 
plethoric development in the first instance, the after weakness 
beiag a consequence of the disease. Roses that succumb to some 
disease akin to gum on the Briar are perfectly healthy on their 
own roots, and I have a Cos’s Golden Drop Plum all but a 
skeleton through gumming, whilst the stock on which it had besn 
worked is perfectly healthy, the stock being Green Gage, and 
fruiting freely. 
The facts, therefore, on which we rest are—first, healthy stocks 
as the basis of immunity from disease, whether it be in the 
origination of new or the perpetuation of improved kinds, for by 
whatever means this is effected we have little to hope for but 
the perpetuation of disease in the progeny of a diseased parentage. 
The seed is no alleviation, as gumming is quite as pronounced 
in the stone of a Peach or Plum as in the branches, therefore 
rejection must be made of both when diseased as agents of repro¬ 
duction. Second, the avoidance of what, through inducing over¬ 
luxuriance, is cilculated to and does predispose to disease. Third, 
keep from sudden checks to growth and their reaction. 
In contending with the disease we have to make as sure as cul¬ 
tural judgment can of the cause or inducements. In the case of 
Peach and similar trees it may arise from looseness of soil, defi¬ 
ciency of calcareous matter, too rich humus-forming matter, de¬ 
fective drainage, whereby the soil is made sodden and sour, and 
too close and moist an atmosphere. Checks, such as injudicious 
ventilation when the external atmosphere is sharp and cold, ex¬ 
treme or full disbudding instead of little and often, large reduction 
ot growths, and keeping the tender growths constantly wet in dull, 
cold periods. The remedy for looseness of soil is to firm it; for 
deficiency of calcareous matter is to supply chalk or marl, clay marl 
to light soil, siliceous marl to heavy ; too rich or humus soil is to 
correct it with lime, or phosphates (mineral coprolites), or marl; 
inefficient drainage suggests rectification, and a close atmosphere 
will prompt freer ventilation. Checks by whatever caused have 
their remedy in a judicious pursuing of opposite treatment. 
The best remedy against the disease is destruction of the 
affected parts, but which, strictly followed, would in many in- 
stan:e 3 mean the destruction of the trees. What we insist upon is 
No. 2037.— Vol. LXXIX., Old Series. 
