The first line of defense, if a plant is not heavily affected by pests, is to pick bugs, slugs and snails from the plant and squash them. Pests have yet to develop a resistance to this type of control.
Pests like mites are usually most severe on plants in heated homes during the winter, when the air is dry and there are no natural enemies to keep them under control. Raising the ambient humidity through humidity trays, saucers of damp pebbles placed under each plant, or even a room humidifier can help.
For mites, aphids, mealy bugs and other insects, a gentle brush or jet of water can kill and dislodge them from plants. Regularly washing the foliage thoroughly with soapy water, wiping every leaf and rinsing with a sink sprayer is one way to bring populations down.
Soaking is a third way water can be used to combat insects. Completely immerse the pot and potting medium of the affected plant in a bucket of water overnight to evict ants, roaches, sow bugs and pill bugs from the medium.
Soak a cotton swab in 70 percent isopropyl (rubbing) alcohol and dab scale, mealy bugs, mites and aphids off orchids. The alcohol dissolves the insect’s waxy covering, and is a good tool to reach the pests hidden down in the sheaths and leaf crevices. Pay particular attention to the midrib, other veins and leaf edges. Repeat the treatment at seven to 10 day intervals to remove successive generations.
Another method is to spray alcohol, mixed with a few drops of mild liquid soap, from a misting bottle or small pump sprayer. Avoid strong or excessive amounts of detergent, as this may damage your plants, particularly buds and flowers.
Alcohol can be combined with insecticidal soaps, but not with oil, and should never be used near fire. One of the advantages to using alcohol is that insects do not develop resistance to the treatments.