In the Garden:
Western Mountains and High Plains
January, 2005
Regional Report

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Washing the foliage and stems with homemade soap spray or a botanical oil such as neem can help keep spider mites at bay.

A Commonsense Approach to Controlling Houseplant Pests

Most of the tropical houseplants we grow indoors were selected for their adaptability to our home environments. However, there are several insect pests that are also well adapted to living on these tropical plants. Purchasing pest-free plants is the best defense against an invasion, but even if you have good intentions, bugs happen! Why not start the new year by resolving to keep insects from getting the upper hand. It just takes some commonsense strategies.

Quarantine New Plants
After you acquire any new plants, place them in a location away from existing plants. Check the new ones for pests, such as aphids, scale, mealybugs, and tiny spider mites, every 5 to 7 days. In the early stages of their life cycles, pests can be difficult to see, so get a magnifying glass to look at the plant stems and foliage, up close and personal.

In some cases, you may not find the adult insects, but you may see eggs on the foliage if you look closely. Pests attach themselves where a source of sap can be easily obtained. Such areas are the veins of the leaves -- especially on the undersides of the foliage -- tender plant stems, the tips of succulent growth, flower buds, or any other parts of the plant where the tissue is soft rather than woody. The one exception, is soft brown scale, which feeds on the woody stems of ficus and hibiscus.

If no pests appear after about a month, you can be fairly certain that the houseplant is clean and it can be placed among other plants. A good gardener, however, will never stop being observant. This just makes good sense because early detection saves much work later.

Removing Pests
When a few pests are found on a portion of the plant, cut it off and dispose of it in a plastic garbage bag. Mealybugs and scale can be rubbed off woody stems with a cotton swab dipped in rubbing alcohol and soapy water. You may have to do this weekly to get any egg stages that were left behind. So, get out the magnifying glass and check.

Wash Them Off
Washing the foliage and stems with homemade soap spray (1/2 teaspoon mild dishwashing detergent per 8 to 10 ounces of water) or a botanical oil such as neem oil can also keep pests at bay. Place the solution in a spray bottle and keep it agitated to keep it in suspension. Do not apply soap sprays or oils if the plant is wilted or when the sun is shining directly on the leaves. This may cause some leaf burn from the wetting agents in the soap spray. It is also helpful to rinse the plant under the faucet after applying a soap solution if the plant foliage is sensitive to certain detergents or added ingredients.


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