392 
JOURNAL OF HORTICULTURE AND COTTAGE GARDENER. 
C JTovcm&cr T, 188&- 
light green with a decidedly blue tint, shining, and with a meali¬ 
ness in its location rendering it less assailable by water or insect- 
destroying solutions than common green fly—indeed, it is rather 
difficult of dislodgement and destruction, yet not so hard to kill as 
brown or Peach aphis, nor so impervious of attack as black or Cherry 
aphis. Plum aphis (A. pruni), however, gives trouble enough, and 
if unrestrained prejudices the crop, causing the fruit to be cast or 
preventing its development, the deposits also interfering with the 
proper elaboratory functions of the leaves. What with the sap 
abstracted and the deposition of honeydew upon the leaves, which 
sooner or later is taken possession of by a black fungus, the trees 
are greatly impoverished, the fruit being ill fed and the foliage 
falls prematurely. Nor does the mischief end with the current 
crop, as the foliage being cast early the wood is poorly stored with 
food, and the bloom buds do not attain to full development. In 
result the trees may blossom beautifully, but very little will set, 
or if setting the insipid fruit does not swell, being lost in its 
early stages. The remedies for aphides are legion. Tobacco 
water—one gallon of tobacco juice diluted with six gallons of soft 
or ram water syringed over the trees so as to thoroughly wet the 
whole, particularly the young growths and the under sides of the 
leaves, is effectual. Apply it on a calm warm evening, and wash 
the trees with clean tepid water the following evening, or if the 
attack be severe repeat the application of tobacco water, and 
thoroughly cleanse the foliage the following morning by syringing 
with clear tepid water. Tobacco water may be made by soaking 
1 lb. of the strongest shag tobacco in six gallons of boiling water, 
covering it, and allowing it to remain until cool, then strain it 
through a hair sieve ; 1 lb. of softsoap added will render it more 
efficacious. Of all the remedies soapsuds, where bleaching powder 
or much soda is not used, is a cheap, easily obtainable, and a good 
killer of aphides. The suds ought to be strained through a hair 
sieve, and syringed over the trees in the evening. Unless, however, 
it is known for certain that soap and a little soda only are used it is 
perhaps best to leave soapsuds alone, though when they can be relied 
on they are excellent as a wash for fruit trees from the fruit setting 
until midsummer, the soapsuds being followed within twenty-four 
hours with clean cold water, forcibly applied with a syringe or 
engine. Nothing surpasses soapsuds and cold water as a Plum 
aphis destroyer. 
To show that there is no excuse for premature defoliation of 
Plum trees through attacks of aphides we may mention a solution 
of softsoap, 4 ozs. to the gallon of water, as handy and effectual, 
and all the more so if a gallon of tobacco water be added to every 
five of the soap solution. In the soapsuds we have soda, and in 
softsoap potash, which constitutes the difference between hard and 
soft soap. The soaps have a decidedly alkaline reaction, the pro¬ 
portion of alkaline bases being 8 to 9 cent, of soda and potash 
respectively. Then there is quassia water—1 lb. quassia chips 
boiled in four gallons of rain water for a quarter of an hour, 
allowed to cool, and after straining 1 lb. softsoap is added, and when 
thoroughly dissolved syringe the tree thoroughly on a calm evening, 
and follow in half an hour with clear tepid water. 
There are many other insecticides, all of which are, so far as 
we have tried them, efficacious when the directions are strictly 
followed. Plum aphides, however, require a rather stronger appli¬ 
cation than is advised for green fly, and sometimes it is very 
tenacious, in which case gas liquor may be used, diluted with not 
less than twice its bulk of water. If used too strong it will brown 
the foliage, therefore it is well to use two parts of water and one of 
the gas liquor, well drenching the trees with a fine-rose syringe or 
engine, and wash off with clear water the same evening as the 
diluted gas liquor is applied. Repeated on two or three consecutive 
evenings it is certain to effect its purpose, and is equally useful 
against brown and black fly ; not the least of its merits is that of 
its having considerable manurial value. Perhaps it may favour the 
development of fungi, as nitrogenous matter has a decided tendency 
that way. That, however, is given for what it is worth, and the 
gas liquor is certainly less objectionable than insecticides of a 
decidedly poisonous nature, such as Paris green, though that is 
a certain destroyer of insects ; 1 lb. of the preparation mixed 
W1 “b thirty gallons of water syringed on the trees is certain 
to effect its object. It must not be used on trees that have the 
fruit advanced, and which will not have several forcible syringings 
with clean water after its application, and never where there are 
vegetables beneath the trees, and it must be kept from the hands 
of the operator, as it will be sure to find the least scratch, and 
produce serious ulcerations. Poisonous insecticides ought never to 
be trusted in the hands of the inexperienced—the most careful 
cannot be too cautious, and all should adhere as far as possible to 
t ie safest, leaving the dangerous to experts. 
In last year’s Journal of Horticulture , December 13th, 1888, 
page 532, I directed attention to the very troublesome red rust 
or red fungus. In 1887 it was first noticed infesting a few 
leaves of some trees against a wall under glass. Its attacks were,, 
so far as we noticed, confined to the trees indoors, and had no- 
apparent prejudicial effect on the crop. In 1888 the trees inside- 
were much infested, the fruit as well as the foliage being seriously 
damaged, the trees being defoliated by early September. In 1888- 
the fungus attacked some trees on a wall adjoining the Plum house,, 
and it spread in virulence proportionate to the distance— i.e., the 
tree adjoining the Plum house was as badly attacked as any in the 
house, and lost their leaves almost as early, the attack on the other 
trees on the wall being less as the distance increased, ceasing at the 
eighth tree, where there is a break from Plum to Pear trees. Other 
trees farther away were free from attack. 
This year there has not been, as we anticipated, any mitigation,, 
but rather an increased severity of the fungus attacks. In the house 
there was a determined attack of aphides, which succumbed very 
tardily to tobacco fumigations, and syringings were freely given to- 
cleanse the foliage. Singularly there was no attack this year by 
the small green • caterpillars, either in the house or on the trees 
outdoors that in the previous year were attacked by the fungus,,, 
but wherever the fungus appeared in 1888 aphides attacked in 1889. 
The fungus did its work so effectually that though we had a fuU 
crop of fruit it did not attain perfection. It partially ripened, butr 
the fruits did not reach their full size, and had little flavour. Green 
Gage, for instance, had less than the quality of Orleans, and Jeffer¬ 
son and Coe’s Golden Drop were less palatable than Victoria, in 
fact the dessert varieties were less saccharine than the usual 
culinary varieties. The foliage was cast shortly afterwards— i.e. r 
after the premature ripening of the fruit, and whilst it remained 
with the fruit the spores of the fungus were shed in a very abun¬ 
dant minute powder, giving the upper part of the Plums a coating 
of black or deep purple. So light and minute is the dust that a 
puff of wind might blow it anywhere. The trees were defoliated 1 
for the most part early in September, not all the leaves falling, but 
those earliest and most severely attacked, and the characteristic is- 
that the upper part of the trees lose the foliage soonest. 
Trees on the wall outdoors attacked by the fungus in 1888 were 
still worse this year ; even Victoria, which escaped in 1888, was- 
defoliated when the fruit should have been ripe, for the ripen¬ 
ing was not more than partly or badly done. The worst infested 
was Purple Gags, and Green Gage was so badly attacked that the 
fruit in one instance did not ripen, or only so indifferently that- 
even wasps would not trouble to eat it, and they have been more 
voracious than usual this year. 
The fungus has spread to other trees on walls over a hundred 
yards away. Being the first year of attack the foliage was still on 
the trees on October 21st, indeed fruit was on one tree—viz.,. 
Roe’s Autumn ; in fact the fungus pervades nearly every tree, and it 
is most effective on trees that have the most soft growth, as for 
example a Belgian Purple on a north aspect, though late attacked,, 
was completely defoliated by early September. Albeit, some 
Damson and Winesour trees were equally as early, the fruit of the- 
Damsons shrivelling on the trees. 
This defoliation is strictly due to the fungus, for be the trees 
ever so clean an attack of the fungus is certain to cause early 
defoliation. That it is common to all the Plum tribe, and affects- 
equally the wildling as well as those cultivated, whether in the open 
or under glass, I hope to prove to you by the specimens accompany¬ 
ing—viz., leaves of the Bullace taken from a tree in a shrubbery- 
adjoining the garden, and which I consider is the parent of all the 
mischief in this case, others from trees against a wall, and some front- 
trees under glas3. There is no question, so far as I can make out, 
of the identity of the fungus. It spread from the Bullace to the 
Plum house, came, as I hinted last year, through the top lights in the 
late summer or autumn of 1886, infested the Plum house in 1887, 
extended to the trees on the wall adjoining in 1888, and over the 
whole garden in 1889. This points to the prevention of disease in 
Plum trees by the removal from the neighbourhood of Sloe, Bullace,. 
and kindred trees, as both disease-producing insects and fungi live 
on such and spread to others of the same kind. 
As the fungus lives inside the leaves it is not to be reached 
after the red spots appear. It takes nourishment from the leaves 
and prevents the proper fulfilment of their functions, but it opens, 
in due course on the under side of the leaves, and then sheds its 
spores. Syringing with a solution of potassium sulphide effects a 
radical change in the persistence or life of the leaves, and it may- 
effect the destruction of the spores. I am trying it, and am satisfied 
of its beneficial tendency. Then all the leaves as they fall are col¬ 
lected and burned, and this with the syringing with the solution of 
potassium sulphide, half an ounce to the gallon of water, not omit¬ 
ting the floor and border, and pointing the ground over in early 
spring before the young leaves burst from the buds is expected to 
mitigate if not insure freedom from attack. Perhaps it would be 
as well to employ softsoap solutions alternating with quarter of an 
ounce potassium sulphide solutions before the buds burst, and after 
