How to Control Scale Insects on Outdoor Plants

One Methods:Apply One or More of These Remedies

�Scale" is an insect that can infect your outdoor plants and cause a huge infestation in surrounding plants, including your fruits and vegetables. The name comes from the insect's characteristic hard green or brown shell. These insects feed on plant nectar or sap, eventually killing the plant, and excrete a sticky liquid called "honeydew." If you see the insects or this substance on your plants and suspect that they have been infected with scale, there are several things you can do to get rid of this pest.

Apply One or More of These Remedies

  1. Image titled Control Scale Insects on Outdoor Plants Step 1
    Prune infected branches and make sure to destroy the removed branches by burning or treating with an insecticide so as to not infect other plants.
  2. Image titled Control Scale Insects on Outdoor Plants Step 2
    Apply beneficial insect predators, such as parasitic wasps or ladybugs.
    • Put the predators directly on the plant; once they have eaten all the scale insects, they will leave.
  3. Image titled Control Scale Insects on Outdoor Plants Step 3
    Spray the plants with mild soap and water.
    • Mix 2.0 tsp. mild liquid soap (9.8 ml) with 1.0 gallon (3.79 l) of room-temperature water.
    • Transfer the mixture into a spray bottle or sprayer that attaches to your hose.
    • Spray the mixture to thoroughly coat the stems and both sides of the leaves.
    • Thoroughly rinse off the mixture from leaves and stems using room-temperature water.
  4. Image titled Control Scale Insects on Outdoor Plants Step 4
    Spray with a horticultural oil, such as neem oil; a horticultural oil is safe for other insects and plants.
  5. Image titled Control Scale Insects on Outdoor Plants Step 5
    Scrub the scales off using a soft brush and mild soap using the same mixture as above for spraying.
  6. Image titled Control Scale Insects on Outdoor Plants Step 6
    Spray with commercial chemicals or insecticides following the manufacturer's instructions.


  • Make sure that all plants, even those not being treated, are thoroughly watered before treating with any sprays or releasing the predators.
  • To protect sensitive flowers and plants, fruits and vegetables and your pets, try to use the least toxic method for controlling scale before using chemicals or insecticides.
  • If using a liquid soap, make sure that it is not a detergent as they can be too harsh on sensitive plants.
  • If using the soapy mixture described above, make sure that you apply at least once a week for a month or more or until no evidence of insects remains.


  • With any chemical or insecticide, be sure to read the label very carefully for hazards to your health or the environment, and to ensure that the ingredients are those recommended for the types of plants in your garden.
  • If you decide to use chemical sprays, be sure to protect yourself with adequate clothing and safety gear such as a long-sleeved shirt, long pants, gloves, goggles and spray mask or respirator.
  • After applying any chemical or pesticide, be sure that you wash any exposed areas thoroughly with soap and water. It is best to remove exposed clothing outside of the house (e.g., in the garage) so that it cannot contaminate other clothing, furniture, pets or houseplants.

Things You'll Need

  • Pruning shears or clippers
  • Mild liquid soap
  • Measuring cup
  • Water
  • Bucket for mixing (at least 2-gallon [7.6-L] capacity)
  • Funnel
  • Spray bottle or sprayer for hose
  • Garden hose
  • Soft brush
  • Protective clothing

Article Info

Categories: Garden Pests and Weeds