NOTES AND ABSTRACTS. 
477 
A distinction is to be drawn between the various forms of cankers on apple 
trees. The author classifies them as follows : Frost cankers ; apple-tree 
canker, caused by Physalospora Cydoniae ; fire-blight canker, caused by Bacillus 
amylovorus ; apple-tree canker, caused by Nectria ditissima ; and blister canker, 
caused by Nummularia discreta. There are also the apple-bark canker, caused 
by Myxospovium corticolum, and the bitter-rot canker, caused by Glomevella 
cingulata ; these two being of lesser importance. 
Frost Cankers. — In severe winters frost is a very active agent in the production 
of cankers. Some varieties of apples {e.g. ' Tompkins King,' ' Twenty Ounce,' 
' Hubbardston ') are more susceptible than others. The cankers are frequently 
formed on the bark of the trunk and at the origin of the chief branches. 
New York Apple-tree Canker, caused by Physalospora Cydoniae, may attack 
the limbs as a canker, or the fruit, forming a black rot ; or the leaves, forming 
a leaf-spot. The canker arises from a wound in the bark, and forms a series of 
concentric rings on the bark. This after a period falls and exposes the wood 
and a callus, from which arise numerous scattered pustules containing spores. 
European Apple-tree Canker, caused by Nectria ditissima, attacks the cambium 
of successive years and produces a series of concentric calluses from year to year. 
This form produces spores and perithecia. 
Fire-blight Canker, caused by Bacillus amylovorus, also attacks the bark. 
In the spring, when the causal bacteria are active, the advancing margin is 
indefinite. Occasionally drops of liquid exude from the lenticels. When the 
bacteria are less active, the margin of the canker becomes very definite and a 
prominent crevice marks it. The diseased bark sinks and remains relatively 
smooth. 
Blister Canker, caused by Nummularia discreta, may produce blackened 
areas on the bark, which fall off and expose the wood. On these portions 
stromata of the fungus develop, which present a blistered appearance and are 
large and black. 
The control of cankers presents much difficulty, but the affected limbs must 
be removed and burnt together with the diseased bark from the trunk. Then 
the wound may be treated with some preservative {e.g. tar, asphaltum) to 
prevent entrance of further spores. Sometimes grafting a non-susceptible 
variety upon an erect-growing variety such as ' Twenty Ounce ' is useful. — A. B. 
Apple Drying. By J. Farrell {Jour. Dep. Agr. Vict. April 191 6, pp. 196- 
211). — This article gives plans of buildings for evaporating fruit, construction 
of evaporator, its trays, also of the sulphuring chamber, with material required 
for constructing an evaporator, illustrations of peeling machine and trimming 
apples ; it explains the method of peeling, coring, slicing, trimming, brining, 
sulphuring, drying, and packing. The dried product is 10 to 15 per cent, in 
weight of the fresh apple ; the cores and peels are made into cider or jelly, or 
dried for stock food. — C. H. H. 
Apple Orchard, Protecting by Dusting. By D. Reddick and C. R. Crosby 
{U.S.A. Exp. Stn., Cornell, Extension Bull. 1, May 1916). — Excellent results 
are reported in dealing with apple scab and codling-moth by dust-spraying, which 
is said to be easier, more efficacious, and quicker than spraying with a liquid. 
The mixture applied was 85 per cent, of exceedingly fine sulphur (95 per cent, of 
which would pass a sieve with 200 meshes to the lineal inch) and 15 per cent, 
of equally finely powdered lead arseniate. The amount of the mixture required 
is about \\ to i\ lb. to a tree each time, and it is best applied on a calm morning 
while dew is still on the leaves. The times for application are (1) when the 
blossom buds show pink; (2) just after the petals have fallen ; (3) three weeks 
after the petals fall, and (4) four weeks later still. — F. J. C. 
Apple Orchards, Economics of. By C. I. Lewis and H. A. Vickers {U.S. A . Exp. 
Stn., Oregon, Bull. 132, 104 pp. ; 14 figs.). — Facts and figures for fruit farmers. 
E.A.Bd. 
Apple, Fungi producing Heart-rot in. By B. O. Dodge {Mycologia, viii. 
p. 5, Jan. 1 91 6 ; figs.). — Polyporus admirabilis, Spongipellis fissilis, and S. 
galactinus are said to cause rotting of wood of apple-trees, generally entering 
through a wound. The author doubts the value of painting over large wounds, 
as he believes cracking is bound to occur and spores may thus find their way in. 
It will, in any case, give a partial protection from such entrance, — F. J. C. 
Apple Root-rot. By C. H. Crabill {Phytopathology, vi. p. 158, Apriri9i6). — 
The root-rot here described is characterized by cessation of growth, loss of 
