In Print – Carolina Gardener – Handling Houseplant Pest

The November/December of Carolina Gardner is out. Included in this issue is my story on Handling Houseplant Pests.  Unfortunately, it cannot be downloaded.   Pick up a copy today!

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Handling Houseplant Pests


There are many reasons to add houseplants around the home – to freshen the air, to bring calmness to a room, or to charm a corner.    But when houseplants fall prey to pests, their charm can be eluded.

If caught early, houseplant pests are easy to rid.  The best course of action is to not bring infested plants home, but if they are, treat them as soon as they are realized.

Before purchasing a new houseplant choose carefully.  Look under the leaves and at the stems for signs of pests.   For those houseplants at home, inspect regularly.  Most pests attack weak plants, so keeping your plants healthy and happy are also a must.

By knowing how to identify the most common pests before purchasing a houseplant and being able to identify a pest on an existing houseplant so that it may be treated quickly, is your best defense.


Most common pests include aphids, fungus gnats, mealy bug, spider mites, scale, and whiteflies.


Aphids can be black, gray, orange, and green.  Their movement is slow.  At first glance, they appear to be motionless, but look closely, and you will detect very slow movement. Typically, they can be found in clusters on the undersides of leaves, on flower buds, at the growing tips, and where the leaves meet the stem.

To treat, simply take the affected plant and spray either under the tap for small plants, or in the tub shower for larger plants.  The water pressure will knock them off and they will go down the drain.  If the infestation is particularly bad, spray the houseplant with an insecticidal soap.

Fungus Gnats

These tiny black flies are often found flying around houseplants.  They are mainly a nuisance and won’t hurt the plant.  Getting rid of them is easy since they live only in overly moist soil.

If you have fungus gnats, it’s a sign of overwatering your plants.  To treat, simply water less often and they will disappear.  If they are particularly troublesome, unpot the plant, wash the soil from the roots, and repot with fresh soil.

Mealy bugs

Mealy bugs look more like a tuff of cotton than a bug.  Typically, mealy bugs are found adhering to the plant where leaves join the stem, and sometimes in the roots, as well.

To treat, moisten a cotton ball with rubbing alcohol and wipe them off.  Repeat in a week or so in case any eggs were left behind.

For a severe infestation, spray the plant with an insecticidal soap. If you have root mealies, wash all the soil off the roots and repot with fresh soil.


A scale infestation is when the leaves look like they have scabs on their “skin.”

Scale attach themselves to the undersides of leaves and is protected by a hard outer shell, making insecticidal soap sprays useless.

To treat a light infestation, moisten a cotton ball with rubbing alcohol and wipe down each leaf.  For more involved infestations, try spraying with Neem oil.  If an infestation is heavy and the plant has begun to turn yellow, disposal is the only option.

Spider Mites

These tiny spider-like insects are hard to see with the naked eye.  The first sign of infestation are white webs that appear between leaves and stems. They thrive in hot dry conditions.  Under watering creates an idea condition for spider mites.  Mist leaves regularly, especially in winter when central heating dries out the air.

To treat an existing infestation, give the plant a shower under the tap or in the tub, and repeat in a week or so.  If infestation is advance to where the plant is losing leaves, spray with an insecticidal soap.


These tiny, moth-like insects rise above a moved plant in a great cloud before resettling.  They usually occur in large numbers and spread quickly from plant to plant.

Winged adults are the stage most commonly seen; however it’s the feeding of the immature nymph stage are what causes the damage to the leaves.  Whitefly nymphs are scale-like in shape, translucent color, and fairly immobile.  Feeding on the leaf undersides, whitefly nymphs are often inconspicuous and easily overlooked.

Getting rid of them is difficult.  To treat, spray every three days with an insecticidal soap.  If this doesn’t work, the plant should be disposed of.

The best defense against houseplant pest infestations is prevention and early treatment.  Keeping houseplants healthy by matching the plant with the right light and water, and avoiding the extremes, will give you and your houseplants many years of enjoyment.


To make houseplant insecticidal soap, add about 6 drops of a liquid detergent into a quart spray bottle.  Fill with water, shake.

Commercial products are also available.

Pick up a copy today!

Copy by Helen Yoest

Helen Yoest is a garden writer and coach through her business Gardening With Confidence Follow Helen on Twitter @HelenYoest and her Facebook page, the Gardening With Confidence fan page. Helen also serves on the board of advisors for the JC Raulston Arboretum.


  1. TC said

    Good stuff Ms. Helen.

  2. Janet said

    Great job Helen! Will be subscribing to Carolina Gardener magazine, have read it off and on for a few years.
    One of my favorite EASY ways to get rid of fungal gnats is a little cider vinegar in a glass (shallow glass) with a few drops of dish detergent in it. bingo…they are all floating!

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