402 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
[ Jane 18,1891; 
^st ten years old, not too long to wait for such a handsome Orchid. 
Cattleya labiata presents an astonishing range of variation, and it is 
therefore not surprising that though hybrids between that type and 
Lselm purpurata have been previously obtained, as in the superb Lslias 
bella and callistoglossa, yet the distinctions are strongly marked in all 
the progeny hitherto flowered, and the grand addition now under notice 
IS a success of a remarkable character. 
L. hybrida Arnoldiana appears to be of vigorous habit, the narrow 
fusiform pseudo-bulbs being 6 to 8 inches long, the leaves about 
L. inches long, inches across, of very stout and bright shining green. 
The flowers exceed 7 inches in diameter, and have a peculiarly graceful 
outline and pose ; the sepals are narrowly lanceolate, of a delicate 
evenly diffused rosy purple hue, regularly spreading ; the petals are of 
similar colour, broader, drooping, or deciirving at the tips, the margin 
undulated, and slightly darker veins in the centre. The lip is very 
handsome, the broad rounded central lobe nearly 3 inches in diameter, 
of an intensely rich magenta crimson, with a few still darker veins, and 
a golden bronze tinge in the throat. The whole aspect of the flower is 
very striking, and the hybrid must be assigned a place among the finest 
y^t r^is6cl, 
APPLE SCAB—CRACKING IN PEARS, 
The Apple “ scab 
IS 
^ minute parasitic fungus called 
Cladosponum dendnticum, WaU, which attacks the leaves 
Apple tree, but is more commonly 
noticeable on the fruit itself. On the leaves its advent is marked 
Uackish speck on the upper surface, which 
gradually increases m size until it becomes visible to the naked 
eye as a minute black spot, and continuing to enlarge, attains 
varied proportions. Usually the spots are a quarter to half an 
inch across but the larger the foliage and grosser the Apple tree, 
f?om “oL of tbe fungus. In good examples^? attains 
from one-third to two-thirds of an inch across, and under a 
brnTi^bf beautiful object, because its mycelial threads 
nrn^-^ resemble a coniferous tree of exquisite 
proportions, whence the species name dendriticum—tree-like.^ The 
not generally develop conidia, but the short 
division of the threads of the 
mycelium by cross walls, may (and do) break off, and falling or 
esting on a suitable nidus, act as spores, push out mycelium or 
S“of the the fungus. This early condition or 
f^enTr^Hv^! Spilocoea pomi, and 
generally is the early condition prevalent in the fruit Certainlv 
leave, oeeurs iJ 
infsa^rn 1A A ^ stage, of the fungus development, but when 
infection 13 made sure, and always towards the latter part of the 
season, spores or conidia are developed abundantly both by the 
leaf and shoot infestations, and these are scattered over, r^ain 
on, and live through the winter attached to the young shoots and 
upon the sea es of the buds of the infested tree ready foi thSr 
awakening into life the following spring by the sun’s warmth and 
genial showers of ram, whilst the leaves, sered and withered are 
riven far and wide, bearing their weight of spores, and thus 
carry infection to any trees they may come into contact with. 
snnf. mif irregularly rounded 
S+b ^^epressed in the centre, the outside surrounded 
with a whitish margin, which is the skin or epidermis of the fruit 
and around the margin there is a dark reddish border, representiim 
flesh oTthr/rdt.*^^^'"''^^''" spawn threads between the^ skin and 
nn is occupied by an immense 
number of minute bodies (invisible to the naked ejeother than as 
a mass), which under a powerful lens are found to be club-shaned 
(spores), generally one- 
celled, though occasionally, yet rarely, two-celled. ^ These are fixed 
din?? ®iiort stalks to the 
densJy matted mycelium or stroma, ivhich consists of closelv 
^rol's^wair^ The’sJr division of the mycelium threads by 
r -1 threads remain almost wholly in the skin 
on ? interior not being penetrated beyond a few (sort of 
anchor-hke) branch threads here and there, the funo-us confining 
its foraging to the cells of the epidermis, or between Those and the 
next layer. Continuing to spread the spots run into each other 
and cover a large portion of the fruit, often causing, it to crack 
through the contraction of the skin and subsequent rttemots at 
swelling which greatly disparages its appearance,\sin. aSarkeJ 
value. Even in mild attacks the fruit is considerably hamnered 
in swelling, that side infested always attaining less size than the 
other, and mvanably diminishes the first-claTs fnd SLaTe" ^he 
alSherkl'thE^ the frnit 
• ^ Cracking ’ in Pears is even worse than “scab” on Apples— 
in tact, the worst form of the fungus prevails on the Pear. It not 
only grows on the leaves, shoots, and fruit, but attacks the flowers, 
often preventing their setting, whilst it siezes on the footstalks of 
TP?.!, thern to fall or receive indifferent nourishment. 
lie fruit IS beyond its setting stage it is crippled in its growth, 
and rarely attains any value through the devastation of the fungus, 
w ich cau^s it to have black depressed patches, and cracks in 
rrii® fruit, after penetrating to the core, rendering it 
worthless. This fungus—Fusicladium (Cladosporiiim) pyrinum, 
l<ekL differs little from the scab fungus on Apples ; it is only less 
regular in form of the spore stalks, the “clubs” break off with 
disease which accelerates the spread and malignity of the 
As the fungi prey on the leaves and young shoots the infested 
trees are not only injured in their current crops, but those of the 
future are greatly prejudiced. The shoots do not grow freely, 
ere ore are stunted, hypertrophied, and distorted, whilst the 
eaves are prevented elaborating the sap, and assimilated matter is, 
in consequence, ill stored in the wood and buds for the healthy 
continued fruitfulness of the tree. Indeed, trees 
afflicted with “ scab ” and “ cracking ” are always more or less 
unprofitable and often “ cumber the ground.” 
Scab on Apples and “cracking” in Pears are very common 
diseases. They are caused by the fungi named. “ The weather ” is 
too lame an excuse now to travel beyond the boundary of neglected 
gardens and orchards ; but the disease is found in the best of 
cultures from the steppes of Russia to the sierras of California, 
and from the Shetland Isles to New Zealand. It thrives every- 
Apple and Pear trees where the spores have reached. 
All Oladoponum wants is an Apple or Pear tree whereon to grow. 
T ungus-like it revels in moist weather, nowhere so happy as in an 
orcha,rd with the hedge broken down and the ditch full of water ; 
ut it likes the Apple or Pear none the less when growing in 
ground where the water must run. Indeed, good sites and favour¬ 
ing cultural conditions always tell against disease ; but apart from 
those considerations the fungus thrives on the Apple and Pear 
everywhere. It is only a question of spores and “ a sweet glow of 
moisture and warmth ” to insure germination and a full develop¬ 
ment of the “plant.” That poveity and ill condition of subject 
favours the spread of parasites goes without saying ; but that is 
no reason why those conditions should not be remedied before the 
plague appears, and when it does appear take prompt steps to 
arrest its progress. f r i 
It answers no useful purpose to credit “the weather” with the 
unusual prevalence of the Apple “scab” or Pear “crack,” for 
after all the great question is to find the most suitable remedy to 
employ in the destruction of the causes of the mischief, and it 
must be stated that whilst we find consolation in abusing the 
weather our American friends are combating the disease. The 
employment of sulphate of copper as a fungicide has long been 
known and successfully employed in France, and from there it 
passed to Arnerica. There Professor Scribner, whose researches in 
vegetable pathology have rendered his name famous, has found 
that sulphate of copper is one of the most effective fungicides that 
can be used. Experience has proved that this substance in varied 
modification of the Bordeaux mixture annihilates most, if not all 
parasitical fungi. In France it has proved a specific for Vine 
mildews and the Potato disease, and in America for every kind 
of rot ; but there is one kind of fruit it has not proved suitable 
for, and that is the British Apple. The chief difficulty up to 
Mree years ago was to find something strong enough to kill the 
Cladosponum without injury to the foliage of the Apple and Pear. 
That seems to have been found at last. Instead of using sulphate 
ot copper, atnmonical carbonate of copper solutions have been 
employed with considerable advantage. 
-D Division of Vegetable 
Pathology, United States Department of Agriculture, Washington, 
J” Canadian Horticulturist,” vol. xiv., p. 144, gives 
the following on the “ Treatment of Apple Scab.” 
Apple scab can now be prevented so easily and cheaply that 
there is no longer any excuse for the injury it occasions. We first 
successfully treated this disease three years ago (1887), and since 
mat tirne our methods of work have been considerably improved. 
TTTu ® treatment we ivould now recommend is as follows :_ 
i!, the fruit is about the size of a pea, spray the trees 
thoroughly with a solution made by dissolving 5 ozs of 
carbonate of copper in U pint of aqua ammoffla, having a 
strength of 2G . The copper may be dissolved in an ordinary 
water-pail. When completely dissolved pour the liquid into a 
barrel, and then filUhe latter with (50 gals.) water. A barrel of 
the solution made m this v/ay will cost about 35 cents. (174d.) 
and it will be sufficient to treat fifteen (thirty) large trees o'nce! 
Make a second spraying twelve or fifteen days after the first 
