close up picture of a branch from a tree with scale bugs all over it

Scale Insects on Houseplants: How to Identify, Treat, and Prevent Them

Scale Insects on Houseplants: How to Identify, Treat, and Prevent Them

Scale insects are among the trickiest houseplant pests to manage because of their hard, protective shells. They attach firmly to stems, leaves, and even roots, feeding on plant sap and leaving behind sticky honeydew that attracts sooty mold. With over 8,000 known species worldwide, they vary in size and color but share one thing in common: persistence once they infest a plant.

Identification & Damage

a close up of a tree stem covered with dark brown scale bugs on the branch

  • Appearance: Small, oval, dome-shaped or flat bumps on stems and leaves. Colors range from brown, tan, and white to translucent.

  • Damage Symptoms: Yellowing leaves, stunted growth, sticky honeydew, sooty mold, premature leaf drop. Severe infestations can weaken or even kill plants.

  • Life Cycle: Scale begin as mobile “crawlers.” Once they mature, they form shells and become fixed in place, making them much harder to treat.

a close up picture of a stem of a plant with a scale bug on it that's brown and dome shaped

Origins & Spread

Scale insects thrive in warm, humid environments and are common worldwide. Indoors, they typically arrive:

  • Hidden on new plants or cuttings.

  • In contaminated soil.

  • Crawling between plants placed close together.

Pests Are Normal—Don’t Panic

A common question plant owners ask is: “Why do my plants keep getting pests?” The truth is, if you grow plants, you’ll eventually see pests—and that’s okay.

Scale infestations don’t mean you’ve failed as a plant owner. With the right preventive measures, treatments, and products, scale can be managed effectively. At Urbane Eight, we help make pest control less overwhelming by giving you proven, science-backed solutions.

Biological Control with Koppert Solutions

Instead of relying on home remedies, Koppert’s biological products are reliable and sustainable:

  1. Cryptobug (Cryptolaemus montrouzieri)

    • Predatory beetle also called the “mealybug destroyer,” which feeds on young scale crawlers.

    • How it works: Both adults and larvae hunt early-stage scale before shells harden.

    • Best conditions: Warm, humid environments.

  2. Chrysopa (Chrysoperla carnea)

    • Lacewing larvae that feed on scale crawlers and other soft-bodied pests.

    • How it works: Larvae actively seek out and consume crawlers.

  3. Parasitic Wasps (Metaphycus spp. & Anagyrus spp.)

    • These tiny wasps parasitize soft scale species, killing them from the inside out.

    • More common in greenhouse/orchard systems but can be applied to indoor setups too.

  4. Sticky Traps 

    • Useful for monitoring crawler movement and adult males, helping track population spread.

Other Effective Treatments You Can Use

Alongside beneficial insects, you can use indoor-safe treatments for scale insects:

Safer’s Insecticidal Soap

  • How it works: Breaks down the protective coating of young scale crawlers.

  • How to use: Spray directly on affected areas, making sure to coat undersides of leaves and stems. Repeat every 7–10 days.

Diatomaceous Earth

  • How it works: Scratches and dehydrates crawlers as they move across surfaces.

  • How to use: Dust lightly on soil and around plant bases to disrupt spread.

Dr. Doom Indoor Plant Spray

  • How it works: Fast knockdown using pyrethrins, effective against mobile crawlers.

  • How to use: Spray directly on infested areas. Avoid flowers.

Using Beneficials with Other Pest Control Products

Important: Sprays, soaps, and powders can kill beneficial insects just as easily as pests.

  • Release beneficials first, then wait before applying other treatments.

  • Avoid overlap—if you’re using Cryptobug or Chrysopa, don’t spray insecticidal soap at the same time.

  • Choose your approach: Stick with beneficials for natural suppression or use sprays/powders if you need quick knockdowns.

Integrated Pest Management (IPM) for Scale Insects

  • Release Cryptobug and Chrysopa preventively to attack crawler stages.

  • Use parasitic wasps for more established infestations.

  • Pair with sticky traps for monitoring.

  • Spot treat with insecticidal soap or Dr. Doom spray if not using beneficials.

  • Apply diatomaceous earth at the soil line to disrupt crawlers.

  • Quarantine new plants before introducing them to your collection.

Frequently Asked Questions

Why are scale insects so hard to get rid of?
Their shells protect them from most sprays. Targeting them at the crawler stage with beneficial insects is most effective.

Do scale insects spread quickly?
Yes—crawlers move easily between plants, making early detection critical.

Are scale insects harmful to humans?
No, but they cause significant plant damage and can spread rapidly indoors.

Conclusion

Scale insects are stubborn, but they don’t have to take over your houseplants. With a combination of biological controls, safe sprays, diatomaceous earth, and careful monitoring, you can protect your plants year-round.

At Urbane Eight, we provide everything you need—from Koppert’s Cryptobug, Chrysopa, and parasitic wasps to Safer’s Insecticidal Soap, Dr. Doom Indoor Plant Spray, and Diatomaceous Earth.

Shop Urbane Eight today for proven scale insect treatments and keep your collection thriving.

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