How do I identify scale insects on indoor plants?
Written by
Liu Xiaohui
Reviewed by
Prof. Martin Thorne, Ph.D.Identifying scale insects on plants indoors means knowing where they are likely hiding out. I always check the undersides of the leaves first, where the brown soft scales gather on clustered ferns. The scale will appear as dome-shaped bumps that won't wipe off easily. These bumps are actually the protective covering of the insect that is feeding underneath.
Visual Inspection
- Examine stems and leaf veins for immobile bumps
- Check for irregular shell shapes unlike uniform plant parts
- Look for cottony egg sacs near leaf joints
Tactile Clues
- Gently scrape bumps with fingernail - scales won't detach
- Feel for sticky honeydew on leaves below infestations
- Notice sooty mold developing on honeydew-coated surfaces
Magnification Check
- Use 10x loupe to spot tiny crawlers near adults
- Identify scale species by cover shape and color
- Confirm living insects versus mineral deposits
Schefflera plants often have hemispherical scales that appear to be little brown domes on their leaves. I like to show my clients the tape test: simply push clear tape against any questionable bump. If it sticks, then you have a scale and not some harmless growth on your plant. The tape test works quite nicely for small scale insects under 2 millimeter in length.
Evidence of honeydew residue is indisputable. Additionally, suppose you can run your finger under the leaves and feel the sticky residue. In that case, you're definitely indicating that soft scales are feeding above. You can also place a piece of white paper under your plant and shake it. If you observe any black specks, these represent sooty mold, which are spores feeding off of honeydew.
Don't mix up scales with mineral deposits. Real scales have antennae or legs visible under a magnifying glass. I check weekly with a very bright flashlight held at a 45-degree angle. This creates shadows from raised scales, which doesn't happen with flat mineral deposits. The sooner you catch the scales, the better chance you have of preventing them from getting out of control or spreading to the other plants.
Read the full article: Mastering Scale Insect Identification: A Complete Guide
