If you encounter any pesky little pests, you must follow the specific instructions under that pest. In general, if insects or mites do become established on your plants, consider using a registered insecticide or miticide to rid the plants of these pests. If pest infestation occurs, act quickly because once established, insects multiply rapidly.

Healthy Soil

Experts say healthy soil can prevent about 80 percent of insect damage. Healthy soil breeds healthy plants that are better able to resist pests.

Common Pests

Mealy Bugs: 

These are white/gray insects about 0.1 inches in length. These bugs consume the cactus sap and reproduce rapidly by laying their eggs underneath a cotton-like covering. Mealy bugs are covered with these white spots and sticky texture. You will find these pests on the stem or spines of the plant. If left untreated, the cactus will stop growing, take on a sticky appearance, and begin to shrivel.

Non-chemical treatment:

• Physically remove these bugs by using external objects such as fingernails, scrub brushes, tweezers, and/or water pressure.

• Apply rubbing alcohol onto the insects by using a cotton swab. Rubbing alcohol will dissolve the waxy coat and kill the mealy bugs.

Pesticides:

• Use systemic or contact insecticides such as malathion and dimethodate to control widespread mealy bugs.  Weekly applications of malathion or dimethodate are recommended to prevent recurring mealy bug attacks.

• For root mealy bugs, remove the cactus from the pot, rinse off all white spots and soil with lukewarm water. Then, allow the plant to dry. After the plant has dried, you can repot the cactus in a well-drained, fresh cactus mix.

Red Spider Mite:

Mites are small, reddish insects less than 0.2 mm long. Red spider mites may also appear as brown dots or red pepper on young growth.Found on the top of the plant, these mites begin as pale yellowish spots and later turn rusty brown. Without treatment, these red spider miters lead to scarring and sometimes webbing on the plants

Non-Chemical Treatment:

The reddish-brown mites thrive in hot dry conditions, yet dislike humid conditions. Acting as a preventive measure and cure, overhead watering and spraying plants may reduce mite attacks. In addition, increase the humidity to prevent further attacks of mites.

Aphids:

Aphids are greenfly and blackfly seen on garden plants may occasionally invade the greenhouse and start a colony on a leafy succulent. The majority of aphids are female and produce a rapid sucession of live young. In the autumn, males appear and fertilize the females so that eggs can be produced to survive the winter. As with other sap feeders, aphids produce honeydew which in turn encourages black mould. Aphids appear on the body of the plant and are plant-specific. That is, aphids tend to congregate on one or closely related species of plant.

Treatment:

Spraying with most insecticides is usually effective. A repeat treatment may be applied after a few days.

Pesticides:

Apply miticide for widespread red spider mite problems. You can also use an all-purpose bug killer called “Rose and Flower Insect Killer,” which can help eliminate mite problems.

3).  Spray safety

Chemicals should be a last pest-control resort. Many pesticides are harmful to people, and though they do kill pests, they also kill soil nutrients and beneficial insects. If you must spray something on your plants, start with plain water—it will kill some insects and force off many others. For a little more power, add an insecticidal soap to the water spray. Insecticidal soaps, made from the fatty acids of animals and plants, are both safe and effective in controlling soft-bodied insects.

4).  Preventive measures:

When you purchase plants, make sure that you keep newly bought plants isolated for about two weeks before placing them with other plants.  The time allows for any diseases or pests to become apparent and controlled before the plant problem spreads.