How To Identify Common Garden Pests

Common Houseplant Pests
- how to identify and control them -

Posted on August 6, 2018

Common Houseplant Pests

Your pampered houseplants present a tasty smorgasbord for insects that feed on plants. The healthier your plants are the more enticing they will be. It's possible for a plant to coexist with a few pests but the problem comes when one or two insects multiply into a full-blown infestation. Too many insects feeding on a plant can cause significant damage. There is also the risk of pests spreading from one plant to other nearby plants. Help keep your houseplants safe by learning to identify common insect pests and how to control them.

The Most Common Pests on Indoor Plants

Mealy bug

mealy bugs on houseplant
White cottony masses found along the stems and underneath the leaves are actually soft-bodied insects. Mealy bugs use their sharp mouth parts to pierce plant tissue and feed on sap.

Spider mites

spider mites on houseplant
Spider mites feed and lay eggs on the undersides of leaves. They're quite tiny; a magnifier is helpful for identifying them. Plant symptoms include webbed areas along the stems, yellowing foliage, and tiny eggs and debris on the leaf undersides.

Scale

scale insects on houseplant
Smooth, rounded bumps along stems and on leaves are the protective shells of the scale insect. Scale use their needle-like mouth parts to feed on plant sap, so they can remain in one location for a long time.

Fungus gnat

fungus gnats on houseplant
Tiny flies that are attracted to moist soil where they lay their eggs. The larvae, once they emerge, feed on decomposing organic matter in the soil and plant roots.

Aphids

aphids on houseplant
Soft bodied insects that suck plant juices through the leaves and stems. They're often found feeding on the soft tissue found at a plant's growing tips, tender new leaves, and undersides of leaves. Plant symptoms include curled, distorted new growth and a sticky residue on the foliage.

Thrips

thrips on houseplant
These tiny winged insects can be difficult to see without a magnifier. They may be easier to identify by the damage they cause. Thrips puncture plant tissue by tearing it away with their strong mouth parts and they suck the plant juices from the wound. Areas where they've scraped away plant tissue are thinned and often appear as brown or silvery blotches.

Whiteflies

whiteflies on houseplant
Whiteflies can be found on the undersides of leaves or flying near a plant. They pierce plant tissue and suck out the juices. Plant damage can include yellow, mottled foliage and leaf drop.

Roaches

roach on houseplant
Roaches are common indoor pests whether or not you have houseplants. Normally they aren't a problem, but houseplants do provide moisture and shelter that a roach could find appealing. Don't entice roaches by putting un-composted food scraps or beverages into your houseplants.

Where do houseplant pests come from?

It's surprising how many ways insects can find their way to houseplants. Here are a few of the most common:

Fresh produce from the garden or the grocery store
Cut flower bouquets
Potted gift plants
Newly purchased plants
Plants kept outdoors for the summer
Potting soil
Carried in on clothing
Open windows – tiny insects can even get through window screens

Managing bug infestations on indoor plants

What to do if you find insect pests on your houseplant:

At the first sign of a bug problem, move the infected plant away from other plants.
If possible rinse the plant with water in a sink, tub or outdoors to try to physically remove as many pests as possible from the foliage.
Rubbing alcohol in a spray bottle or cotton swabs dipped in rubbing alcohol can be applied directly on the insects. The alcohol evaporates quickly, killing the pest without harming the plant.
Pests can't survive dish soap. A mix of 1/2 teaspoon dish soap mixed in a quart of water in a hand-sprayer can be sprayed directly on pests.
Insecticidal soap is a commercially available product for spraying indoor or outdoor plant pests. Use according to package directions.
If the outbreak is small, and you're not bug-squeamish, insects can be manually removed with tweezers or paper towel.
Chemical insecticides for houseplants are available. Check the product label to make sure the insect you are trying to control is listed, that the product can be used on your specific plant, and that the product is safe for indoor use.

Tips for preventing pest infestations on your houseplants

The best way to prevent insects from taking over your plants is by catching them before they get a chance to "make themselves at home". Here are some tips for keeping pests from bugging your houseplants:

Inspect plants thoroughly at time of purchase. Avoid any plant with obvious pests, including insects flying around the plants.
To avoid infecting existing houseplants be sure to isolate a new houseplant for about a month. Keep a close eye on it until you've established that the new plant is pest free.
Keep plants clean. Remove dead foliage and wash the plant leaves periodically with water.
Use a magnifying glass to occasionally inspect plants for pests.
If plant has had a serious infestation, replace the soil with fresh potting mix after treatment.
Make sure plant gets the recommended amount of light, water and fertilizer (check plant label) to keep it in optimum health.
Keep away from cold or hot drafts found near windows, doors, or air ducts that could stress and weaken a plant.
Always use sterilized potting mix when repotting plants.

Sometimes, despite your best efforts, it can be hard to get insect pests under control. If the population has managed to grow quite large, the plant can become disfigured, defoliated, and unattractive. The best control method, in a case like this, may be to simply discard the infested plant and replace it with a new, healthier plant. Trying to salvage one infested plant can put all of your plants at risk.

The insects common to houseplants are highly adaptable and very skilled at hiding within a plant to protect themselves. They can be a little tricky to control, but certainly not impossible, especially if you catch them early. Knowing what to look for and being able to correctly identify houseplant pests can make all the difference in keeping your plants healthy and insect-free.

Fruit Flies

Fruit flies are tiny flies that are attracted to ripening fruits and vegetables - not to your houseplants - but they're often confused with fungus gnats. The easiest way to tell them apart are the fruit fly's distinctive red eyes.

Fluoride Damage

fluoride damage
Many sources of public water contain fluoride. Fluoride is good for people's teeth, but not for plants. Watering houseplants with fluoridated water can result in a toxic accumulation of the mineral in the plant's tissue. The resulting brown leaf tips and edges caused by fluoride should not be confused with insect damage. Watering with distilled, rain, or filtered water will prevent your plants from developing this condition.