The Culture of Vegetables and Flowers From Seeds and Roots / 16th Edition

by Sutton & Sons Ltd.

When adverse weather operates injuriously on vegetation the plagues that infest garden plants usually acquire increased power in proportion to the degree of debility to which vegetation is reduced. This circumstance perfectly accords with the general law of Nature, and is full of instruction as to the means of saving plants from serious injury by vermin. The keen, dry east wind that so often jeopardises fruit crops is usually followed by visitations of fly and maggot, and in this case the cause is beyond human power or forethought. But neglect of watering and air-giving to pot plants can be avoided. Good cultivation not only insures fine specimens, but is often the means of preventing the plants from failing under the attacks of Aphis, Mealy Bug, and other enemies against which the gardener has to fight an unceasing battle.

Insects are among the frailest of living creatures and they perish at a touch. As they breathe through the pores of the skin, water alone—the promoter of life and cleanliness—is death to them; and they are still more subject to sure destruction when to the water is added an active poison, such as tobacco, or a substance that adheres to them and stops the process of breathing, such as glue, clay, sulphur, soft soap, and the numerous preparations that are specially made to annihilate insect hosts.

The various stages through which the larger insects pass place them within our power at some period of their existence. The butterfly may float beyond the reach of harm, but in the caterpillar or the chrysalis state it can be dealt with effectually. Again, we may be powerless to destroy the Chafer grubs as they feed or hibernate beneath turf, but in their perfect state as Cockchafers or Rose Chafers many may be beaten down during quiet evenings, and others can be shaken from Roses at dawn or sunset. A knowledge of the life-history of injurious insects will suggest what is to be done and the right time for doing it, so that often by simple treatment they may be destroyed.

The expense of preparing mixtures and washes may be in some degree lessened by economy of application. A drenching-board fitted on a firm frame, should be provided in every place where plant-growing is carried on to any extent. The board should slope from a resting ridge at the base. The plant in its pot may be laid on the board, with the bottom of the pot against the resting ridge, and a pail should be put to catch the liquid used as it drains from the plant after syringing. Every general washing or fumigating should be followed by another at an interval of from a week to a fortnight, because, although the first operation may kill every insect, there will be many living eggs left, and these renew the race, and very soon bring the plants into as bad a state as ever, unless consigned to a happy despatch as their parents were. In some cases it will be more economical to feed than to destroy the vermin; and, as a rule, feeding vermin does not add to their numbers, in the same or any future season, for insect life is so strangely dependent on certain conditions of temperature, &c., that if the season is not favourable to a particular kind it will be scarce, no matter how plentiful it may have been in a previous year. In the case of the Turnip Fly, feeding is frequently the cheapest and surest way of saving the crop. It is customary with Dahlia-growers, and, indeed, with the growers of florists’ flowers generally, to sow Lettuces where the flowers are to be planted, for so long as Lettuces are on the spot Slugs and Snails will prefer them to other food. As the Lettuces themselves serve the purpose of traps, the Snails and Slugs congregated about them may, towards evening, be caught and destroyed.

In using a mixture for the first time, it is advisable to try it on one plant only, and that, of course, the worst in the collection affected. If the preparation is too strong, the truth will be declared by the state of the plant within twenty-four hours; thus a little caution may prevent a great loss. Another good rule is to employ the several remedies in a rather weak state until experience has been gained, for not only has the strength of the medicine to be considered, but the management of the patient before and after it is administered. It is above all things important to be thorough in the cleansing of plants, because they succumb rapidly to the attacks of insects, and should be effectually and promptly cleaned or consigned to the fire. If left in a foul state they spread the infection to all around. In the space at our command it is only possible to notice a few of the garden pests, and we begin with one of the most frequent and troublesome of plant foes.

Aphis in some form or other is the most persistent and perplexing of plant pests. The Green Fly is the enemy of the softer kinds of vegetation, and the Blue and the Black Fly are common plagues of the Peach-house and the orchard. The tender body of the Aphis is instantly affected by conditions unfavourable to its life, and it is therefore easily killed; but its marvellous power of reproduction renders its extinction impossible, for in every instance a few escape, and very soon re-establish their race. Two methods for the destruction of Aphis are in vogue. One is fumigation by tobacco, either pure or in some of the numerous preparations offered, including several popular insecticides which have nicotine as a basis. These are both clean and effective. When a houseful of plants is infested no time should be lost, and the evening is most suitable for dealing with the pests. The plants ought to be quite dry and the house closely shut. A dense cloud of smoke without flame is required. Allow the smoke to do its deadly work during the night. Early next morning syringe the plants freely, and in the course of an hour or so give air. The other remedy is to use one of the many liquids which are inimical to the life of Aphis and other insect pests. To economise the liquid it is advisable to fill a pail or tub and immerse the plants individually. Take one in the right hand and spread the fingers of the left hand over the surface of the soil to prevent an accident; then turn the plant over and plunge the foliage in the liquid, moving it up and down briskly two or three times. If this is not practicable syringe the plants, taking care to wet the leaves on both sides. On the following day syringe with pure soft water.

Rose trees may generally be cleansed of fly by means of the garden engine and pure water only, the essential point being to direct the water on the trees with some amount of force for several evenings in succession whenever the fly threatens to obtain the mastery.

Soft soap dissolved in water makes a cheap and effectual wash for exterminating all kinds of Aphis, and to these ingredients quassia may with advantage be added. One pound of soft soap will suffice for ten gallons of water, into which stir the extract obtained by boiling one pound of quassia chips in water. Pot plants can be dipped in it as already advised, or the solution may be applied by means of the syringe. On the following day the plants should be cleansed with pure soft water.

The Bean Aphis, also known as the Bean Plant Louse, or Black Dolphin (Aphis rumicis). Our illustration shows the wingless female and pupa natural size and magnified. The pupa is black with greyish white mottlings, while the female is deep greenish black in colour. This insect commonly attacks the young shoots and tops of Broad Beans. It is well to cut off the infected tops and burn them. Should the attack be repeated spray the Beans with a solution of soft soap and quassia.