In California various types of scale insects infest citrus trees. For several years I tried spraying or using systemic pesticides (and then having to destroy a crop) before I started thinking about the scale bugs habits.
Scale insects are flat, oval bugs that suck sap from the leaves and branches of a number of different plants, including grapes, mock orange, citrus, and ornamental shrubs such as euonymus. Some scale insects are covered with cottony white tufts that look like lint.

Often the first sign that a plant is infested is a trail of ants. The ants are harvesting “honeydew” which is sap that leaks from the plant as the insects drink.
Ants carry fungus on their mouth that often produces a sticky sooty residue on the fruit and plants. The sooty black residue is another sign of scale infestation.

When scale insect infestation becomes severe, leaves will begin to show yellow mottled regions and small branches may die.
In the spring, the scale insects mainly attack young tender growth, but move to the branches just before winter. Often eggs will be laid on the branches and when they hatch in the spring, the larvae will seek out the young growth.

This summer I began to paint the scale insects on my citrus trees with dish detergent – the cheapest brand I could find. Everywhere I saw scale, I coated it with dish detergent.
Within two weeks my plants had very little scale insect problems. I attached a jet sprayer nozzle to my hose and literally sprayed off the sticky scale bugs.
Not only did the detergent make the insects come off the leaves and branches easily, they were also dead. It seems that the detergent suffocated them. After everything dried off, I re-coated the trees with more dish detergent.

Even the most stunted tress have doubled in size this year and they are full of fruit. I also used old spice jars to make ant bait traps (attach them in the trees out of reach of children), with mixture of boric acid and sugar to reduce the ant population.
I can do this in California because we seldom have rain in the summer which would wash away the detergent. This winter I will be closely watching the trees to see whether or not they are re-infested.
I anticipate needing to use the detergent on a regular basis as this is controlling, and not eradicating the scale insects. If you live in an area where the weather permits you to try this, please do so and let me know how it works for you.
How to Get Rid of Scale Infections with Dishsoap
Getting rid of scale insects using dish detergent is a straightforward and eco-friendly method. Scale insects can be tough to control because they have a protective shell-like covering, but a simple soap solution can help manage these pests effectively. Here’s a detailed guide on how to do it:
1. Prepare the Soap Solution
- Ingredients: You’ll need a mild liquid dish detergent and water.
- Ratio: Mix about 1 to 2 teaspoons of dish detergent per gallon of water. It’s important to keep the solution mild to avoid damaging the plants.
- Jet Sprayer Nozzle: I recommend you just use a jet spray nozzle to apply
2. Test the Solution
- Before applying the soap mixture extensively, test it on a small area of the plant. Wait 24 to 48 hours to see if there are any adverse reactions, such as leaf burn or discoloration.
3. Apply the Solution
- Method: Use a spray bottle or a garden sprayer to apply the solution. Ensure the spray covers both the tops and undersides of the leaves where scale insects are often found.
- Timing: It’s best to apply the solution in the early morning or late evening to avoid direct sunlight, which can increase the risk of leaf burn when combined with the soapy water.
4. Repeat the Treatment
- Scale insects can be persistent, so you might need to apply the soap solution every few days until you no longer see any signs of infestation.
- Frequency: Typically, repeating the treatment 2-3 times, about 4-7 days apart, is effective.
5. Monitor the Plants
- After treatment, keep an eye on your plants for a few weeks to ensure that all the scale insects are gone and that there are no new infestations.
- Check for any signs of damage or stress in the plants, adjusting your care routine as necessary to help them recover.
6. Rinse the Plants
- A day after each application, it’s a good idea to gently rinse the plants with plain water. This helps to remove any residue of the soap solution and minimize the risk of harming the plant.
7. Preventive Measures
- Inspect new plants: Before introducing new plants into your garden or home, inspect them thoroughly for scale insects to prevent an infestation.
- Plant health: Keep your plants healthy with proper watering, lighting, and fertilization, as healthy plants are less susceptible to pest infestations.
Using dish detergent is an effective way to deal with scale insects, especially for those who prefer not to use chemical insecticides. However, it’s crucial to follow the instructions carefully to avoid damaging your plants.
JRodgers
For more information and to identify scale insect pests, check on these websites:
- https://cisr.ucr.edu/california_red_scale.html
- https://cisr.ucr.edu/citricola_scale.html
- https://www.ces.ncsu.edu/depts/ent/notes/O&T/shrubs/note51/note51.html
Photo Credit: WSU.Edu








