THE FRUIT CULTIVATOR. 
29 
Canker .—This seems to be a constitutional disease, and to aviso 
from a defect in the organization, occasioned by impure qualities 
taken in by the root from an ungenial subsoil. This is a conclusion 
come to from experience; because, in low, damp situations, where 
the subsoil is strong gravelly clay, there the trees are mostly canker¬ 
ed ; while the same kinds planted on a light loam, having a dry bot¬ 
tom of rock or chalk, remain perfectly free from the disease. We 
cannot exactly say how this happens, or describe what the deleterious 
qualities are, which derange and destroy the healthy bark and wood 
of a tree; but, knowing what is stated as the cause to be a fact, all we 
can do to prevent it is, to avoid placing trees in situations where they 
would be liable and exposed to the disease; or if our land be of that 
unfavourable kind, endeavour to improve it by draining, or by any 
means that will prevent the root from sinking into the noxious subsoil. 
Insects —Are the American aphis or coccus, otherwise called by 
naturalists the woolly or frothy aphis. This is too well known to 
need further description. To kill those that are visible, and stop 
their young from infecting the whole tree, a wash must be made of 
soft soap and warm soft water, worked together till of the consistence 
of thin paint. This must be laid on the stem and branches with 
painters’ brushes of various sizes, and pressed into every chink or 
opening of the bark where the insects hide and breed. The action 
of the brush crushes the old ones to death, and the clammy nature of 
the wash prevents all movement of either old or young. One appli¬ 
cation will not be enough to extirpate them, because many of the 
young are safe and lie hidden under blisters of the bark, which;, un¬ 
less first pared off with a knife, neither brush nor wash can reach. 
But if this wash be applied hot, and as often as the insects appear, a 
tree, or any number of trees, may be freed from them in time. Other 
remedies have been suggested, as inferior vinegar, strong soap suds, 
lime water, infusions of tobacco, &c. But whatever application may 
be used, taking the insect in time, that is at the moment it first ap¬ 
pears, will be found the most effectual, and a great saving of time. 
As this plague is related to the cochineal insect, its blood is almost 
as strong a dye, and will discolour the linen of the workmen if allowed 
to fall thereon. 
Aphis, or common Green Fly. This is one of the most numerous 
and common insects, found on many different plants as well as fruit 
trees; but on the apple least of all. On plums, cherries, &c., they 
are often hurtful, as well in checking the growth, as in soiling the 
leaves and fruit with honey-dew which they exude. These insects 
are easily killed or banished by fumigations of tobacco smoke, wher¬ 
ever it can be applied. 
