Much may be written relative to the various diseases to which fruit trees are liable, and also to the prevention and destruction of the various kinds of reptiles and insects, which very frequently deprive us of the first fruits of our garden. The preventive operations are those of the best culture. Autumn ploughing, by exposing worms, grubs, the larvae of bugs, beetles, etc, to the intense frost of our winters, and the moderate use of salt, lime, ashes, etc, are beneficial. Insects may be annoyed, and sometimes their complete destruction effected, by the use of soapsuds, lye, tar, turpentine, sulphur, pepper, soot, decoction of elder, walnut leaves, tobacco, and other bitter and acrid substances; but perhaps the most effectual way of keeping some of the most pernicious kinds of insects under, is to gather up such fruit as may fall from the trees, before the insects have an opportunity of escaping into the earth, or to other places of shelter
Where trees are planted in a bad soil, or unfavourable situations, they often become diseased; when this happens, the best remedy is good pruning, and keeping the trees clean by a free use of soap and water. If that will not do, they may be headed down, or removed to a better situation. Barrenness and disease are generally produced by the bad qualities of the earth and air, by a want of water, or by the inroads of insects. These incidents generally show themselves in the early part of the year. Leaves and shoots of any colour but the natural green; curled and ragged leaves; branches in a decaying state; shoots growing from the roots, instead of from the stem or trunk; the stem diseased in its bark, the gum oozing from various parts thereof, are all proofs of the existence of disease. The Peach tree is subject to a disease called the yellows; and the discoloured leaves and feeble branches are often ascribed to the worms which so frequently attack the root; where these are found, they may be removed by a knife or chisel; but if it should appear that the tree is diseased, it should be removed, to prevent other trees from being infected. The Pear, and also the Quince, and sometimes other trees, are subject to the fire blight; this malady may be completely checked on its first appearance, by cutting off and immediately burning the injured branches. Generally speaking, careful pruning, cleaning the bark all over with a brush, applying soap or tobacco water to the leaves, and occasionally putting good earth and good manure to the roots, will remedy most diseases in fruit trees; removing them from a bad to a better soil will, of course, effect this, where it proceeds from a poorness of land; for the old adage, "Remove the cause, and the effect will cease," will be here exemplified. To cure the oozing of the gum, nothing more is necessary than to cut away the diseased parts of the bark; and by thus assisting nature in casting out the excrementitious, or noxious juices, a complete cure may be effected.
When a tree is affected by mildew, let it be immediately sprinkled with soapsuds, and then be dusted over with sulphur and tobacco dust, or snuff; at the same time, dig around the tree, and examine the soil and subsoil; if it be wet and cankery, it should be taken away, and replaced with good healthy soil, and the ground drained; if, on the contrary, the ground be dry, give it a plentiful watering; the same remedy may serve as a preventive of the extension of blight, if applied in time. When any canker is observed, the part affected must, at the time of pruning, be cut clean out, and the part thus dressed be pared, so that no water can lodge in the wound; when this is done, let a quantity of soot be mixed with water, and a little train oil well worked among it, but so that the mixture finally remains stiff; this may be plastered over all the wounds that have been pruned. The application of this mixture keeps out the wet from the wounds, where it would be likely to lodge, and both the soot and oil promote vegetation. When trees are cankery from having a bad subsoil, it is in vain to apply any remedy till the ground is properly drained, some fresh soil mixed with the natural soil, and the tree replanted. When trees are known to be so situated as to be particularly liable to the attacks of insects or disease, they should be attended to at the time of winter or early spring pruning, in order to destroy the insects in their larvae state.
The following compositions have been known to protect fruit trees from the attacks of numerous insects, by being used as a wash to the trees immediately after pruning. The constitution of some trees will bear a much stronger mixture of ingredients than others; but the proportions, as hereafter described, will not be injurious to any, but will be effectual in the destruction of the larvae of insects.