February P, 1893. ] 
.JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
115 
CANKER IN FRUIT TREES. 
(^Continnecl fromj)age 99.') 
The engravings fig. 23, A to I, are elucidatory of the article on this 
subject on page 27. In A is represented canker as a disease of fungoid 
origin, and not produce! by any predisposing cause, or only indirectly 
by defects of cultural requirements or composition of the soil. The 
wounds are occupied in such cases around their circumference, or some 
part of it, by the mycelial threads or spawn of the fungus, Nectria 
ditissima, are swollen, fissured and scaly, and have an unsightly 
appearance. One such tree in a garden or orchard is sufficient to infect 
a parish, for the spores of the fungus are thrown ofi in countless 
year nor in two or more, but the tree affected dies “ hard,” and as 
speedily recovers when “ managed,” which clearly indicates gangrene due 
to ill-nutrition. This cankerous affection is common in orchard trees 
which are so thickly branched and poverty stricken as to produce fruit 
little larger and almost as sour as crabs. A few doses of Mr. Tonks’ 
mixture, 12 lbs. dissolved bones, 10 lbs. of powdered saltpetre, 4 lbs. of 
common salt, 2 lbs. of Epsom salts, 1 lb. of ground green vitriol, and 
8 lbs. of ground gypsum, mixed, and applied at the rate of \ lb. per square 
yard over the whole extent of soil within reach of the roots early in 
spring, repeating when the fruit is formed, would make such cankerous 
trees assume a different garb, and the wounds instead of gaping wide to 
receive every foul infection would soon be closed by new bark, an 
Fig. 23.—apple TREES INFESTED WITH CANKER. 
numbers, and they germinate under favouring climatic conditions. If 
the spores effect a lodgment on an Apple or Pear tree, and the bark is 
defective, it pushes its germinal tube into the inner bark and causes 
the destruction of the small twig (if such be assailed) in the year of 
attack, or in a larger branch produces a considerable excrescence and 
enlargement of the wound. Its cure is indicated in the figures 
C, D and F. 
In B is seen a different kind of wound, not caused or occupied by 
fungal growths, but those caused by bruises, inimical climatic conditions, 
the burrowings of larvm, and defects of soil—its staple, water-logged, 
or its composition. The wounds are shown in their healing state—the 
defects pointed out on page28 having been rectified and the tree nourished, 
so that instead of having the bark round the wounds somewhat ragged, 
fissured, and scaly, as in ZZ, they are in process of being covered over 
with clean healthy bark, as shown in 7, otherwise this dry gangrene has 
some resemblance to canker caused by fungus. It, however, never 
becomes more than warted around the circumference of the wound, 
seldom is marked by excrescences larger than those produced by 
American blight or woolly aphis, and it does not kill small twigs in a 
instance of which is shown in the white rings around those in the 
tree B. All this form of canker wants is “ management.” 
The following are the particulars referring to the illustrations :— 
Apple tree (A) with canker caused by fungus (Nectria ditissima), and 
Apple tree {^B) without fungal growths in the cankerous wounds. 
“A ” tree references— a, canker caused by fungus in the stem ; h, canker 
killing small branch in the year of attack ; c, branch a year after being 
killed by the fungus; d, branch not entirely girdled ; e, unattacked 
branches, “.ff ” tree references—/, cankerous wounds (due to dry gan¬ 
grene) on stem; y, wounds on the branches—all without fungus. 
Wound references— C, canker wound before cutting out the fungus ; 
B, wound after the canker fungus (mycelial threads) has been cut out ; 
77, result of imperfect operation, the fungus being left in the tree ; 
F, successful operation, the fungal growths being excised, and new bark 
forming over the wound ; G, fungus established, canker well developed— 
i.e., C, two years later ; H, wound without fungus growing in the inner 
bark around it ; I, wound without fungus healing over. Bai', point of 
heading. A, a fungus-infested tree for regrafting. 
Reverting to Mr. Kruse’s case, an analysis of the soil is given 
