This section is from the book "The Gardener's Monthly And Horticulturist V21", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
There are a great variety of insect pests that infest plants, but green-fly and red-spider are most to be dreaded by the window-gardener. Here, as in most other cases, " prevention is better than cure," and if plants are regularly Syringed or sponged over with clean water, there Will be little fear of insects troubling them. If green-fly makes its appearance on roses, geraniums, or other plants, it can be syringed off with clean water, laying them on their sides to prevent the roots becoming soddened with water.
If plants are allowed to get too dry, or are watered irregularly, they are liable to become infested with red-spider, a minute pest, resembling a red cheese-mite. This is specially apt to make its appearance in hot dry windows, and soon renders itself apparent by the leaves turning a rusty brown. Constant moisture is the best cure for it, or plants may be sponged over with soft soap and water. It often attacks Dracaenas, but may be prevented by sponging the leaves with clean water every three or four days. For worms in the soil, lime-water will soon dislodge them; they must be picked off and removed as they come to the surface of the soil. This is rather beneficial to the plants than otherwise. The following decoction is useful for the thrip, red-spider, or green-fly: " Boil an ounce of quassia-chips in three pints of soft water, and either dip the plants or sponge them with the solution after it becomes cool." "We have repeatedly tried this with the best results. If green-fly exists only in small quantities, the fumes from a pipe or cigar will soon settle them, care being taken not to burn the plant in the operation. The best of all remedies against insects is to prevent their appearance by cleanliness, a liberal use of fresh water, and abundance of fresh air during favorable weather.
Plants in close or Wardian cases seldom become infested by insects, owing to the moist and genial atmosphere which prevails in those elegant contrivances.