Get Rid of Scale Insects on Indoor Plants

Discover how to identify and get rid of scale insects on houseplants. Find everything you need to know about these destructive plant pests and how to kill them.

What is a Scale Insect?

Scale are flat, tiny, reddish-brown insects that suck plant juices, leaving a sticky coating on leaves called honeydew. Adult scale insects develop a hard, round shell which can make them difficult to kill. 

They are often hard to see -- a mere 1/8-inch long -- and they like to hide on the undersides of leaves.

Look for scale on the underside of leaves, near the central leaf vein.

Life Cycle of Scale Insects

The scale insect life cycle has 3 stages, starting life as eggs, becoming young larvae called crawlers, then grow to adults.

Adult females settle in a spot on a leaf where they lays eggs under its dome-shaped shell. Some will gather in colonies, while others keep a distance from each other. 

When eggs hatch, the larval stage is extremely small, yet active -- remember, they're called crawlers. They will move on to other parts of a plant and feed on honeydew until they are grown.

Scale insects thrive in warm conditions and are likely to invade plants in the spring and summer months. However, they can show up any time of the year and multiply quickly.

Where to Find Scale on Houseplants

Most scale are found attached to the stems and the backs of leaves, usually along central leaf veins. You may notice the infested leaves or fronds to be weak and turn yellow, and possibly fall off.

Honeydew is excreted as these insects suck on plant juices. This sticky substance can be found on leaves, and also the floor or table beneath the plant. Honeydew may grow sooty mold, which is a black, dusty fungus.

Scale insects can feed on just about any houseplant, but they have favorites: ferns, palms, ficus, and citrus.

Scale insects settling on stem of citrus tree. Image ©Christian Weiß | Dreamstime.com

Disclosure: Guide-to-Houseplants.com participates in affiliate programs. If you make a purchase after following the links on this page, I may receive a commission at no additional cost to you.

How to Get Rid of Scale Insects on Indoor Plants

Young scale insects can usually be controlled with a spray of soapy water. Use mild dishwashing liquid that doesn't contain fragrance or other additives. Mix 2 teaspoonfuls with 1 gallon of room-temperature water. Use a spray bottle to spray the soapy water and coat the leaves and stems thoroughly. Spray once a week for at least a month or until you no longer find insects. Always rinse off the soapy solution thoroughly with room-temperature water.

Adult scale can be more difficult to remove. If spraying doesn't work, use an old toothbrush dipped in soapy water to scrub them off. Heavily infested areas that are badly damaged should be pruned.

Rubbing alcohol kills many houseplant insects, including scale. Dab them with a cotton swab soaked in rubbing alcohol. Repeat applications every 2 to 3 days. This works well, but use it with caution. Covering the whole leaf with alcohol damages plant tissue.

If the infestation is bad, use an Insecticidal Soap made for indoor plants. Make sure your plant is listed on the product label. Read the label carefully and follow the manufacturer's directions for use.

1. Home
›
2. Pests and Diseases