Top 10 Houseplant Pests and How to Fight Back

01/02/2020 | Ken Davis Bugs & Disease, Houseplants, Insect, Insects, Plant Care

by Ken Lain, the mountain gardener

Plants are a natural home addition as the holiday decorations are boxed and stored for another year. After the last cookie, cakes, gelt, and fudge are devoured for the season, the house can feel empty. This is where a new houseplant brings your home back to like.

Houseplants displaced through the holiday season this is a difficult transition back to their ordinary place in the living room. Winter temperature, sunlight, and humidity may not be optimal, which makes them easy prey for plant pests that find their way indoors. Pests have no natural predators inside, and their population increases rapidly. Don’t wait until your houseplants are struggling. Check your indoor plants regularly for signs of insects.

Here are the Top 10 Houseplant Problems and How to Solve Them


Aphids appear as small green, white, or black specks on any part of a plant. They pierce and suck the sap out of all parts of the plant, but especially like tender new growth and the underside of leaves. Aphids reproduce quickly with a complete infestation in just days.

Aphids are soft-bodied insects and can be killed quite easily with Triple Action by Fertilome. Focus this organic spray on the underside of leaves and the outer tips of your plant. Repeat in a week to ensure all eggs are eliminated from your plant as well.

Broad Mites

Their favorite houseplants are African violet, begonia, cyclamen, and several others. They do considerable damage to the growing tips of these plants. Far too tiny to see with the naked eye, but if the tips of your houseplant look stunted, distorted, or the leaves start curling, you should suspect mites. We have a microscope connected to a large screen TV here at Watters if you want to take a really close look for this pest.

Mites spread so efficiently garden manuals recommend disposing of an infested plant. I recommend isolating the plant in the garage or a separate room and drench the infected plant with Indoor Multi-Purpose Spray to see if the plant can recover before disposing of a valued plant.

Fungus Gnat

A pesky fly the size of a gnat that hovers around houseplants, iPad and computer screens, or any light source. Flying adults are not the problem here, but the youngster or larval stage feeds on your plant’s roots. Gnats especially favor damp soil and darker rooms.

Sticky Traps quickly catch the adults, which cut down on the population. For complete control, I recommend applying Systemic Granules with deep watering, then allow the soil to dry out for several days to kill all remaining eggs and larvae. Dryer sheets are an excellent deterrent of future infestation.

Leaf Miner

Squiggly lines running through a leaf are a sure sign of this pest. Leaf Miners are the larvae of small black fly. The fly lays its eggs in a leaf blade, and the larvae feed their way through the leaves until mature enough to fly.

Leaf Miner damage on edible greens, like Swiss chard and spinach and often ruin the crop. On a houseplant, they are simply unsightly. You can trap the adults with blue sticky tape and remove any damaged leaves, to keep new flies from emerging. Triple Action is the best know organic for this pest and can be used on edibles, or inside your home.


Mealybugs look like small cottony white blobs, usually attached to the plant at the stem joints. They slowly feed on plants by sucking them to death. Plants infested with mealybugs often appear to be drying out, even when they have been watered.

Mealybugs are hard to get rid of. Try dabbing mealybugs with a cotton swab soaked in rubbing alcohol. The mealybugs spread fast indoors. If your plant is severely infested, it is best to throw it away and start over.


This tiny insect that attaches to the stem of a plant then covers itself with a hard, oval-shaped shell. Like mealybugs, they slowly suck the sap from plants, leaving them too weak to sustain themselves.

A scale infestation is tough to rid. Pesticides often don’t penetrate their hard outer shell. You can rub some off with a fingernail, or soft brush. I attach this insect from the top and bottom of the plant. Spray every 10 days with Triple Action and drench the roots with Systemic Granules is your best solution.

Spider Mites

Mites leave spider-like webbing on the inside of plants, especially those with this lush foliage and pine-like evergreens. Growing to the size of a pinhead and injure plants by sucking their juices dry. Infected leaves turn totally yellow, brittle, and quickly die.

Isolate infested plants and spray with Triple Action at 14-day intervals until symptoms are gone, and no more webbing is found on the plant.


This tiny wingless bug jumps like a flea several inches in the air when disturbed. With one or two insects on a plant you hardly notice, but when infected, the effect is like a small cloud jumping from the plant, very disturbing.

They favor dark rooms with moist potting soil. Springtails feed on roots with only a little stress on your houseplants. You really notice this pest when the soil drys out, and they wonder for moisture in the basement and bathrooms that become a nuisance. Vacuum this insect up or dust the plant’s soil with Diatomaceous Earth.


These tiny insects (less than 1/25 inch) can do a lot of plant damage. They feed in groups, scrapping leaves, flowers dry, and doing horrible damage to fruits. Thrip attack in suck numbers they weakening plants, distorting growth, and spread disease.

There are no natural predators for this insect indoors, so spray the entire plant with Triple Action at 10-day intervals until new growth emerges clean and without distortion. Focus primarily on the underside of leaves where they like to hangout.


These tiny whiteflies tend to hide out on the underside of leaves and fly up in a puff when disturbed. They suck on leaves and stems, weakening plants and causing distortions and discolorations. Whiteflies reproduce very quickly, so catching them early will make eliminating them easier.

Catch them with Yellow Sticky Traps and spray the entire plant with All Season Spray Oil. The spray must make contact with the insect directly to work. You will most like need to repeat this spray at least once more for proper control.

2020 Free Garden Classes Announcement for next year is very exciting. January classes and instructors are finalized, and the rest of the Spring schedule is coming together nicely. Next year’s classes are going to be good! Here are the topics for the first classes of 2020.

January 11 @ 9:30 am: Houseplant Designs with Professional Style

January 18 @ 9:30 am: Top Landscape Designs with Flare

January 25 @ 9:30 am: Why January is the Month to Plant Wildflowers

Until next week, I’ll be helping local gardeners here at Watters Garden Center.

Ken Lain can be found throughout the week at Watters Garden Center, 1815 W. Iron Springs Rd in Prescott, or contacted through his web site at or

2 Replies to “Top 10 Houseplant Pests and How to Fight Back”

    1. We sell a product called systemic granules as described in Ken’s article

      I recommend applying Systemic Granules with deep watering, then allow the soil to dry out for several days to kill all remaining eggs and larvae. Dryer sheets are an excellent deterrent of future infestation.

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