Plants 101

How to Identify and Treat Pests on Your Plants

There are different types of pests out there and we’ll help you to identify which ones are in your plants and how to get rid of them.

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It’s a moment that every plant parent fears: seeing a bug on their houseplants. Whether it's under your plant's leaves or within the soil, don’t worry: bugs are part of the terriotry of plant ownership but they are treatable.

There are a few different types of pests that affect houseplants, and we know that it can get confusing, so we’re breaking down how you can identify the most common types and how to treat them.

1. Mealybugs

If you notice an oval-shaped insect covered by waxy, white cotton-like filaments on your plant, it is most likely a mealybug. They can be found in different parts of the plant but are commonly found on stem nodes, leaf axels and along the veins on the underside of the leaves, but you may find them in the root system of the plants.

Spot-treat visible mealybugs with a cotton swab or cotton pad dipped in alcohol, then spray all of the foliage down with neem oil or insecticidal soap. Examine your plants weekly for traces of reinfestation.

For our in-depth recommendations on treating mealybugs, check out our mealybugs guide here.

2. Scale

Scale are another oval-shaped pest that are enclosed in a shell-like covering if they have matured enough which makes them impervious to contact-sprays. They are typically brown in color but can also be black or white.

Mostly found along leaf veins or on stems, a mature scale will need to be picked off of your plant manually because contact sprays will not penetrate through the bug’s shell. However, you can try to use a systemic insecticide that will travel through the plants tissue and kill the pest once they take a bite before scrapping off the adults. After you remove all visible scale, the plant can then be sprayed down with a neem oil solution or insecticidal soap which can kill any larvae that haven't created their armor yet.

For our in-depth recommendations on treating scale, check out our scale guide here.

3. Spider Mites

Spider mites are microscopic insects that are usually red or yellow in color. You can easily identify them by the silky webbing they leave behind and grayish stippling on the foliage. They usually congregate on new growth on plants and the underside of leaves.

Boosting humidity in your home can help slow down reproduction of spider mites since they thrive in hot, dry air but it's not a method to eradicate them. Use an insecticide that lists “spider mites” on the label to target pests and spray down the plant. Treat your plant after 3 days, and again on a weekly basis for up to 3 applications.

For our in-depth recommendations on treating spider mites, check out our spider mites guide here.

4. Fungus Gnat

If small bugs are flying around your plant, they’re probably fungus gnats. Fungus gnats are 1/8 inch grayish, adult flies with delicate wings and long legs. They are often found around the growing season, during favorable conditions, flying around the soil. Fungus gnat larvae, however, feed on organic matter within the soil.

We recommend starting to remove these pests by setting up yellow sticky-traps, which can help capture the flying, adult gnats. Incorporating diatomaceous earth or mosquito bits in the soil and repotting your plant in fresh soil can help eradicate larvae. You can also use the Bio-Insecticide as a soil drench to target the larvae.

For our in-depth recommendations on fungus gnats, check out our fungus gnats guide here.

5. Thrips

If you notice elongated insects varying in length from 1-2 mm with a brown or black body and bristle-like wings, you likely have thrips in your plants. Younger stages of thrips will appear more light in color to green.

These pests have piercing mouthparts that feed off of cell guts and the injured plant tissue will have a silvery, stippling appearance. It looks like the chlorophyll is getting scraped off of the plant. New plant growth can cup up distorted and brown, dying tissue may also occur in the areas. Heavily infested plants will have little black dots, which is the pests’ fecal matter.

We recommend keeping thrips-infested plants isolated in a separate area to avoid spread. You can use an insecticide to fight off this pest.

6. Slugs

You might think of slugs as an outdoor pest, but they can affect houseplants, too. Slugs are nocturnal feeders that can vary in color from gray to brown, leaving slimy trails behind.

While these are not as common as other houseplant pests, they may appear from time to time if ragged holes are developing on leaves. They hide under planters and in the soil during the day and can be found directly on the foliage at night when they come out of hiding. You can try leaching the soil if they are dwelling there at night. Otherwise, we recommend looking into slug pellets and traps if an infestation arises.

Words By The Sill

Empowering all people to be plant people—a collection of articles from The Sill’s team of plant experts across a variety of plant care topics to inspire confidence in the next generation of plant parents. Welcome to Plant Parenthood™.

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