Spider Mites and Mealybugs: How to Identify and Get Rid of Them

Spider mites show up as tiny moving specks, fine webbing and pale speckling on leaves, while mealybugs look like small white cottony clumps tucked into leaf joints and under leaves. Both suck sap and both spread fast indoors. The fix is similar: isolate the plant, physically remove as many pests as you can, then treat repeatedly with insecticidal soap or neem oil, using rubbing alcohol to spot-treat mealybugs.

How to identify spider mites

Spider mites aren't insects. They're tiny arachnids, less than 1/20 of an inch long according to University of California IPM, so most people notice the damage before the mites. Look for:

• Stippling: tiny pale or yellow dots across the leaf surface where mites have fed. Heavy feeding turns leaves dull, bronzed or yellow.
• Fine webbing: silky strands between leaves and stems, or across the undersides of leaves, especially at the growing tips.
• Moving dots: hold a white sheet of paper under a leaf and tap it. Specks that start crawling are mites.

They favor hot, dry, dusty conditions and plants that are stressed from lack of water. Indoors, that often means plants near heating vents in winter or sunny windows in summer. Common targets include calatheas, palms, alocasias, English ivy, crotons and scheffleras, but almost any plant can host them.

How to identify mealybugs

Mealybugs are small, soft, oval insects covered in a white, waxy coating that makes them look like bits of cotton or fluff. You'll find them:

• In leaf axils, where leaves meet stems
• Along leaf veins on the undersides
• In new growth and around flower buds
• Sometimes on the roots, as root mealybugs, which you only see when you unpot the plant

Mealybugs produce sticky honeydew, so leaves below an infestation can feel tacky or develop black sooty mold. Their cottony egg sacs are a giveaway. UC IPM notes a female can produce 100 to 200 or more eggs over a 10 to 20 day period. Succulents, hoyas, jade plants, African violets, citrus and dracaenas are frequent hosts.

Why they spread so fast

Indoors there's no winter to slow them down and few natural predators. UC IPM reports spider mites can complete a generation in less than a week in warm conditions, and mealybugs breed year-round in homes. Both travel easily: mites drift between touching plants and hitch rides on hands, pets and clothing, and newly hatched mealybug crawlers wander to nearby plants.

Most infestations start with a new plant that brought pests home with it. By the time you notice, there are usually eggs and young stages you can't see, which is why one treatment rarely works.

Step 1: Isolate the plant

Move the infested plant away from the others immediately, ideally into a different room. Then check every plant nearby, especially ones that were touching it. Look at undersides of leaves and in the leaf joints.

Step 2: Physically remove what you can

For spider mites, take the plant to the shower or sink and rinse the leaves thoroughly with lukewarm water, paying special attention to the undersides. A strong spray knocks mites and webbing off. Wipe broad leaves with a damp cloth. Cover the soil with a plastic bag if you don't want to soak it.

For mealybugs, remove visible clusters by hand with a cotton swab or a soft toothbrush, then rinse. Prune off heavily infested stems or leaves and bag them for the trash.

Step 3: Spot-treat mealybugs with rubbing alcohol

Dip a cotton swab in isopropyl (rubbing) alcohol and dab it directly on each mealybug. The alcohol dissolves their waxy coating. UC IPM suggests a solution of 70% or less, and testing a small area of the plant first, since some plants are sensitive. Check again every few days, because you'll miss some and new ones will hatch.

Step 4: Treat with insecticidal soap or neem oil

Insecticidal soap and horticultural oils, including neem oil, work by contact, so they only kill pests they actually coat. Spray every surface: tops and undersides of leaves, stems and leaf joints. Use a product labeled for indoor plants and follow the label's dilution and timing.

• Apply in bright, indirect light rather than direct sun to avoid leaf burn.
• Test on one leaf first and wait a day, especially on ferns, succulents and plants with fuzzy or waxy leaves.
• Repeat every five to seven days for at least three to four weeks to catch newly hatched pests.

UC IPM cautions against broad-spectrum insecticides for spider mites because they kill the predators that keep mites in check and can make outbreaks worse. Specific miticides exist for stubborn mite infestations.

About systemic insecticides

Systemic products, such as granules containing imidacloprid, are taken up by the plant and kill sap-feeding insects like mealybugs that feed on it. They can help with root mealybugs and persistent infestations that sprays can't reach. A few cautions: they aren't effective against spider mites, UC IPM advises avoiding imidacloprid on flowering plants because of risks to pollinators, and they need careful handling in homes with pets and children. Read the full label, confirm the product is approved for indoor use, and consider it a last resort rather than a first step.

When to give up on a plant

UC IPM's own advice for heavily infested houseplants is to consider discarding them rather than treating them over and over. If a small, inexpensive plant is covered in mealybugs or webbing, bagging it and throwing it out protects the rest of your collection. For a plant you care about, take clean cuttings from unaffected growth, inspect them closely, and root those.

Prevention

• Quarantine new plants for two to three weeks in a separate room, and inspect them before they join the others.
• Inspect regularly. A quick look under leaves when you water catches problems early.
• Keep leaves clean. Wiping or rinsing dusty leaves removes early pests and dust that mites like.
• Avoid drought stress. Water appropriately, since stressed plants attract mites. If you're not sure how much is right, our guide to overwatering vs underwatering can help.
• Raise humidity around plants prone to mites, like calatheas, which also reduces brown leaf tips.

Not sure what you're looking at? Planted can identify your plant from a photo, help diagnose pest and disease problems, and set up a care schedule so you stay on top of checks and watering.

Common questions

Can spider mites and mealybugs live in the soil?

Spider mites live on the foliage, though they can shelter in debris on the soil surface. Mealybugs mostly live on stems and leaves, but root mealybugs live in the soil and feed on roots. If a plant is declining for no visible reason, unpot it and look for white, cottony patches on the roots.

Is neem oil safe to use indoors?

Neem oil products labeled for houseplants are commonly used indoors. Follow the label, use them in a well-ventilated room, keep pets away from wet foliage, and test on a single leaf first. Some products have a strong smell, so many people treat plants in a bathroom or outdoors in the shade and bring them back in once dry.

How long does it take to get rid of spider mites or mealybugs?

Expect at least three to four weeks of repeated treatment. Both pests have eggs or hidden stages that survive a single round, so you need to keep treating until no new pests appear for a couple of weeks.

Can pests spread to my other plants?

Yes, easily. Spider mites move between touching plants and on hands and clothing, and mealybug crawlers wander to nearby pots. Isolate infested plants right away and check everything that was nearby.