How to Get Rid of Scale on Shrubs

Overview

Scale is an insect pest that feeds on the sap of plants. These tiny creatures attach themselves firmly to parts of the plant, usually the stem or undersides of the leaves, and suck the very life out of the plant. They can attack flowers, shrubs, indoor houseplants and trees. Heavy scale infestations can kill part or all of a plant. Because their bodies are covered with a protected waxy coating, scale insects can be difficult to get rid of with insecticide alone. It is necessary to employ more than one eradication method.

Step 1

Determine if you really do have a scale problem. Scale insects often look like tiny bumpy dots on plants. Use a piece of electrical tape to see if you can remove the bumps, or try prying them off with your fingernail. If they come off, they're probably scale insects.

Step 2

Remove heavily infested parts of the plant with pruners. Once scale insects reach adulthood, their waxy bodies or hard armor make it difficult to kill them with pesticides.

Step 3

Coat the remainder of the plant with an insecticide labeled for scale. Reapply every 10 days or until you see the scale activity subside. It will take many applications for the insecticide to penetrate the bodies of the pests. In the spring, before the buds have bloomed, apply a horticultural oil made for the overwintering season. This will kill the eggs that may be dormant in the soil and suffocate any adult scale.

Tips and Warnings

  • Read the insecticide directions carefully. Some have temperature restrictions.

Things You'll Need

  • Electrical tape
  • Pruners
  • Insecticide
  • Horticultural oil

References

  • University of Minnesota: Scale Insects of Trees and Shrubs
  • University of California: Managing Pests
  • University of Illinois Extension: Control Scale Insects
Keywords: scale insects, on shrubs, how to get rid of

About this Author

April Sanders has been a professional writer since 1998. Previously, she worked as an educator and currently writes academic research content for EBSCO publishing and elementary reading curriculum for Compass Publishing. She holds a Bachelor of Arts in social psychology from the University of Washington and a master's degree in information sciences and technology in education from Mansfield University.