1900 SUPPLEMENT—RECENT INTRODUCTIONS, &cC. 151 
. BLACK PARSLEY. See Thapsia decipiens. 
BLACK POPLAR. Sce Populus nigra. 
BLACK RASPBERRY. See Rubus occi- 
dentalis. 
BLACK ROOT. See Symphytum officinale. 
BLACK ROT OF CABBAGE and other Cruciferz 
is of bacterial origin, and the disease is scientifically known 
as Pseudomonas campestris. Though principally found in 
the United States it has been recorded in this country. 
Dr. E. F. Smith, in the United States Department of Agri- 
culture, fully describes it in one of the Bulletins (68). 
Judging from his report, Cabbage and other cruciferous 
plants may be attacked at any stage. The symptoms may 
consist of a dwarfing or one-sided growth of the heads, by 
the absence of any heads, or by the death of the plant. 
Further, he says: “ Occasionally the heads rot and fall off. 
5 If the stumps of affected plants are broken or 
cut across, a brown or black ring will be observed corre- 
sponding to the woody part of the stem, this being the part 
specially subject to the disease. In bad cases this 
blackening may be easily traced upwards into the centre 
of the head, and is generally worse on one side In the 
leaves the symptoms usually begin at the margins, and 
consist in the yellowing of all affected parts except the 
yeins, which become decidedly brown or black.” 
Affected foliage should be uprooted and burned, and in 
bad cases the whole plant should be similarly treated. 
On no account should cruciferous plants occupy the 
diseased quarters the next season. 
BLACK ROT (or BLACK SPOT) OF TOMATO 
(Macrosporium Tomato). A very common and well- 
marked fungoid disease, found upon Tomatoes, whether 
grown under glass or outside. It is more troublesome in 
the former case than in the latter. As the common 
name suggests, the chief characteristic is a dark spot, 
which, as the disease progresses, sinks. Usually the 
spots appear on the blossom end of the fruit, but they 
are not confined thereto, or even to the fruit itself, 
the foliage and stems of the plant being sometimes 
involved. The fungus gains access to the fruit by means 
of a rupture in the skin, and spreads very rapidly, and 
eventually the tissues rot, through the penetration of 
the dark mycelium. The gardener is generally made 
aware of the presence of the fungus when the fruits 
are about one-third grown. 
In the case of plants under glass, the chief predisposing 
causes are too much atmospheric moisture and insufficient 
ventilation, combined with the use of fresh manure. 
Directly the disease is noted, all affected fruit (or, in 
bad eases, plants as well) should be burned, or the trouble 
will be imcreased a hundred-fold. The other plants 
should then be sprayed with sulphide of potassium (loz. 
to 3gall. of water) every ten or twelve days for a time. 
This will prevent it from spreading. Tomato-growers 
would, however, find it much more profitable to spray 
early in the season as a preventive measure. Fruits 
which colour prematurely should especially be regarded 
with suspicion, as such are frequently affected. 
BLACK ROT OF VINES (Lzestadia Bidwellii). 
Though frequently found in this country as well as in 
France, this disease is most prevalent in America, where it 
constitutes the worst of all Grape foes. The common name 
is in allusion to the appearance presented by the affected 
berries. Twigs and foliage are also attacked. Viala, whose 
investigations in connection with this disease are amongst 
the most noteworthy, suggests that something by way of 
prevention might be done by employing stocks which are 
practically proof against the disease. A similar view is 
held by Rathay. : 
The disease is usually first observed on the leaves, for 
though the young shoots may be also affected, the gardener 
is more likely to have foliage and fruit under observation. 
Black Rot of Vines—continued. 
The foliage has reddish-brown spots with darker margins, 
and later the surface is covered with black pustules 
(pimples). These are pycnidia. By this time the berries 
are also involved. The first appearance of the disease 
upon these shows itself, according to Prof. F. D. Chester, 
““as a light brown spot, caused by the decay of the under- 
lying pulp, this spot increasing in size so as to involve the 
entire berry. Simultaneous with this change the parts first 
affected turn black, and become covered with minute 
black pustules. Finally, the entire berry dries and 
shrivels, the skin crumpling into angular folds. The entire 
berry is now uniformly covered with the pustules.” When 
mature, the pycnidia yield stylospores which, if they find a 
suitable resting-place, germinate, and still further increase 
the trouble. The disease is probably tided over the winter 
in ascospores, which remain dormant until the spring of the 
following year. 
The importance of removing and burning all leaves, 
shoots, and fruits showing the disease, as well as those 
which have fallen, will at once be apparent. 
To check the disease when once it appears, spraying with 
the ammoniacal solution of copper carbonate (see Fungi- 
cides) is best. This may be employed, if properly made, 
without injury to either foliage or fruit at intervals of a 
fortnight. The next season Bordeaux Mixture may be 
sprayed on before the leaves expand. Certain conditions of 
Vines and borders predispose to attack in this as in many 
other fungoid diseases, and the cultivator must be par- 
ticularly on his guard against the too liberal use of strong 
manures. 
BLACES. See Athalia spinarum. 
BLACK SALTWORT. See Glaux maritima. 
BLACK SLUG. See Athalia spinarum. 
BLACK SPOT OF TOMATO. See Black Rot 
of Tomato. 
BLACK-VEINED WHITE BUTTERFLY. See 
Pear Insects. 
BLADDER CAMPION. See Silene inflata. 
BLADDER or POCKET PLUMS. This con- 
dition of Plums is due to the presence of a peculiar 
fungus (Hzxoascus pruni), allied to the destructive Leaf- 
Curl of Peaches, &c. It is a most insidious disease, and 
one which materially injures the fruit crop. The gardener 
is not aware of its presence until the young fruits are 
developing in May, when, instead of being firm and healthy- 
looking, and of the normal form, they are distorted, 
elongated, sometimes wrinkled hollow masses of a yellowish 
colour. In late summer, these Bladder or Pocket Plums 
are covered with a glaucous bloom, and finally become 
rotten, though, perhaps, persistent. This powder consists 
of asci, or bags, which contain spores ready to be dis- 
tributed at the proper time. Fruits so affected contain no 
stones. The area of infection is rapidly spread by means 
of these spores; and, therefore, the aim of the cultivator 
must be directed to removing such useless fruits before 
the spores can be liberated. This will not in itself be 
sufficient, as the mycelium of the fungus is also present 
in the branches; hence, therefore, a pruning back of 
the shoots to the old wood is absolutely necessary, or 
year by year the trouble will increase, until the trees 
are rendered quite useless. Where the disease has been 
known to existpin a garden, or even in a certain neigh- 
bourhood, it will be wise “to spray in early spring with 
Bordeaux Mixture, as a precautionary measure. 
On the Continent, as well as in America and in this 
country, the disease is alike very common. For years its 
cause was ascribed to anything but fungus. At one time 
the deformed Plums were thought to be due to a gall- 
making insect as well as to improper fertilisation. Even 
at the present time the exact method by which healthy 
trees are infected is not known. 
