Extension

David Hillock, Senior Extension Specialist in Consumer Horticulture and Statewide Master Gardener Coordinator

Insect pests can occasionally be a problem and can result in plant stress or death.

An occasional “shower” will benefit most plants. Small plants can be showered with water from the spray head at the kitchen sink, and larger plants can be showered with water in the bathtub or shower. The water spray should not be too hard, and it should be tepid in temperature. This will remove dust, dirt, and many insects and pests that might affect the plant. Always inspect plants for pests as you water and care for them.

If insects or pests are a problem, submerging the plants in a tub of water for about 30 minutes may cause the insects to rise to the surface of the water where they can be skimmed off. Enclose the pot in a plastic bag to keep the potting medium in place during this treatment.

Aphids (plant lice) and mealybugs (cottony) are common insect problems of houseplants. Insecticides properly diluted and applied will eliminate most infestations. Then, usually by early isolation and retreatment, the insect infestation can be controlled with minimum insecticide treatments.

Figure 1. Aphids are a common insect problem on houseplants. (Photo highly magnified)

Figure 2. Mealybugs are a common insect problem on house plants. (Photo highly magnified)

Spider mites can also damage houseplants. These are red, black, brown or tan pests that are about the size of a dust particle. They usually feed from the undersides of the leaves causing the top side to turn pale. They are a greater problem during periods of high temperature and low humidity. Showering your houseplants once or twice a month will help control these tiny pests.

Figure 3. Spider mites are very tiny, but can kill houseplants. (Photo highly magnified)

Figure 4. Scale insects suck plant fluids, leaving a sticky residue on nearby surfacs. (Photo highly magnified)

Where only a few plants are involved, an alcohol-soaked cotton swab can be used to wipe off any aphids, mealybugs, and scale insects.

Before treating houseplants with an insecticide, regardless of chemical, put them where there is plenty of ventilation. Allow them to dry thoroughly before bringing them back into the room. Always follow label directions.

Systemic insecticides formulated for homeowner use can be sprinkled in the pots with growing plants to control most insect problems. Consult your local garden center, greenhouse or local OSU Extension Office for the latest pest control recommendations.

Do not apply pesticides without a proper reason. Read and heed all label warning and directions. Do not treat houseplants with pesticides if people with respiratory problems live in the home. Be sure to keep all pesticides and plants that have been treated with pesticides out of the reach of children and pets.