Scale is one of the most common pests plaguing cactus plants, which can be challenging to get rid of.
Scale insects will latch onto the plant’s stems and leaves, sucking out all the nutrients it needs to survive.
If this goes untreated for too long, scale infestation can kill your cacti!
Luckily for you, there are many ways to get scale off your plants once they show up.
This article will discuss everything you need to know about scale on cactus plants and how to treat it on your cacti!
What Are Scale Bugs
Scale bugs are scale insects that suck the sap from cactus plants. They can be brown, red, or black and look like bumps on your plant’s branches.
Scale can infect your plants in the soil, above ground or below ground.
You may have scale on the cactus if you see small bumps under leaves and leaf stems that are pulsing with movement.
This pest is more common during the summer months when scale bugs reproduce quickly because of heat and humidity.
Types Of Scale Insects
There are thousands of scale insects; however, there are only a few types that affect cacti. The scale will look like either oval or flat bumps on the plant’s stems and leaves.
The most common scale is the armored scale.
This scale insect can be recognized by the waxy shell that it secretes around itself to protect its body and eggs from predators, parasites, or fungus.
It feeds on plant juices using needle-like mouthparts called stylets.
The armored scale insects are mostly immobile, which makes them easy targets for scale predators.
The scale bug emits a chemical that prevents the scale predator from eating it.
There are also soft-scale insects.
This scale looks like the armored scale but has no outer covering and is a lighter color than its counterpart.
It emits chemicals that prevent ants from attacking it, feeding on it instead of predators or parasites.
The cochineal scale insect is another common type of scale found on cacti but not nearly as harmful to the plant as armored scale insects are.
This scale was once harvested for its bright red dye, giving foods and other items an appealing color.
However, the cochineal scale is not commercially harvested anymore because of how harmful chemicals can be to produce its dye and other potentially damaging effects it could have on your health.
What Causes Scale on Cactus
Cacti are an incredibly resilient plant, able to survive in arid conditions.
They are also very low-maintenance plants that require little care and typically do not need water for weeks at a time.
However, scale can still be a problem on succulents and cacti because scale insects eat the sap from your cactus plant instead of sucking out juices or attacking leaves or stems.
Scale insects are attracted to cacti because most scale insects feed on a type of tree or shrub, and many scale species have developed a taste preference for the sap in succulent stems.
Scale can get to cactus plants in several ways.
Scale insects may be brought to your cactus plant by ants or other scale insect carriers, by wind-blown adults that have hatched from the scale variety’s eggs, or they could even hitchhike on you when you move plants around too roughly.
Scale insects can infest your cactus if they land on it and attach themselves to the plant. The scale insect will then begin feeding off your cactus sap, which can eventually kill it (or at least damage it).
How To Identify Scale on Cactus Plants
Scale on cactus plants look whitish and can be seen with the naked eye as tiny dots covering your plant’s leaves, stem, or branches.
They are usually found in groups or colonies, which makes them easy to spot.
In some cases, they may even cover whole stems, making it difficult for photosynthesis to occur, resulting in damage to those areas, including yellowing and drop off.
You can tell if your cactus has scale from the symptoms. It can include discoloration of leaves, wilting or drooping, which is a sign that scale has affected its ability to absorb water and nutrients from the soil.
Also, slow growth rate due to nutrient deficiency, small patches on cactus plant turning brown followed by a yellowish hue towards the center of stem area are signs of scale.
At the same time, some parts may dry up and look mottled.
What Damages Does Scale Cause on Cacti
Scale is an insect that lives on cactus plants. Scale can cause damages to cacti by harming the plant’s stems and leaves, causing discoloration.
Scale reproduces itself rapidly, which makes scale more challenging to remove from your cactus plants. Some of the symptoms scale might leave behind are:
- Yellowing spots or brown patches on leaf surfaces
- Deformed new growth (especially in young seedlings)
- Sticky exudate (material secreted by certain organisms) is often called honeydew
- Black sooty mold growing on the surface of scales’ eggs and honeydew
- Premature drop off of flowers buds, fruit clusters, or entire branches
- Twig dieback (death of small-to-large sections of a stem)
- Scale infestation can also be a sign of ants
Scale is generally not fatal to cacti, but it will cause plant damage if left untreated, and scale should permanently be removed from the leaves as soon as you notice them.
How To Treat Scale on Cactus Plants
There are several ways you can get rid of scale on cactus plants.
Some of the best methods are:
Neem oil is a great scale killer. It is a natural oil made from the fruits and seeds of neem trees, also known as Indian lilac or fever tree.
The organic pesticide contains limonoids that are harmful to scale insects but not to mammals.
Neem oil works by suffocating the scale insect, which results in its death.
To use this method, you should mix one part pure cold-pressed neem oil with two parts water and spray it on your cactus plant twice a week for three weeks straight during spring when scale population increases most often.
One good thing about using soap as a pest control agent is that it can be used even on sensitive plants such as those found in the cactus family without harming them at all.
Insecticidal soap is a practical scale killer that kills mealybugs, whiteflies, spider mites, fungus gnats, and other insects.
To use this method to get rid of scale on cactus plants, you should mix about three tablespoons of pure liquid castile or peppermint soap with one gallon of water.
Stir the solution well before spraying it onto your cactus plant until it is thoroughly soaked through its canopy.
You can use a sprayer or soak the plant by dipping the pot into the solution and letting it sit there.
Soap and Water Solution
Another scale killer that you can use is a soap and water solution.
All you need to do is mix one tablespoon of liquid dishwashing detergent or pure castile soap with two cups of water, then dip a clean cloth into the mixture and wipe it gently on your cactus plant until all parts are covered evenly.
Then rinse it thoroughly with plain water afterward.
Rubbing Isopropyl Alcohol
If you want an organic scale killer that is less harmful to house pets and small children, rubbing alcohol may be the best choice.
This scale removal method works by dissolving scale insects’ protective coating on their bodies, so they die due to dehydration.
To use this solution, wet a cotton ball or soft cloth with pure 99% isopropyl (rubbing) alcohol and wipe it gently onto your cactus plant until all parts are covered evenly.
Then let everything dry naturally in a well-ventilated area before bringing back any potted plants inside if needed.
You can also spray some of the liquid into your cactus planter instead of dipping it directly into the solution like you did when removing scale using soap and water solution.
Wipe Them Off
This scale removal method is simplest since you need to wipe scale insects off your plant using a cotton swab dipped in alcohol or some other scale insecticide.
You can even use this method for indoor cactus plants but make sure it stays far away from children and pets who may be tempted to put them inside their mouths.
Note: Do not use any soap solution on succulents with waxy leaves like those found on cacti because they are susceptible to chemicals that might cause leaf burn or death due to desiccation (drying out).
Simply dip the cotton ball into pure rubbing alcohol instead if needed.
If none of these scale-killing methods work well enough for you, then an insecticide spray may be the best scale removal solution to use.
There are a variety of scale killers that work well on cacti, so that you can choose any scale insecticide labeled for scale bugs and cacti plants.
Make sure to read the label carefully before purchasing anything, though, especially if your current houseplant has sensitive leaves because some sprays can also be harmful to them!
How To Prevent Scale on Cactus Plants
The best scale prevention method is to regularly inspect your cactus plants and wipe them clean using a cotton swab dipped in alcohol or other scale insecticide solution if you find any scale insects trying to settle.
There are several scale prevention methods that you can do to ensure scale insects never infest your cactus plants again.
Don’t Overwater Your Cacti
Most scale insects are more likely to show up when your cactus plants are overwatered.
This is because scale insects like moist, dark areas where they can suck on the sap of your cacti without being seen.
Use Succulent Soil for Cactus Plant Growth
Always use a succulent or cactus potting mix that has plenty of sand and grit in it to ensure good drainage and airflow around the roots of your cactus plants.
Place Them in a Well-Ventilated Area
Scale insects tend to thrive best when they have moist, humid conditions, so always place your scale-infested cactus plants somewhere with good air circulation and sun exposure for the best scale prevention results!
Another scale prevention method is to repot your cactus plants every few years because scale insects can lay eggs in the soil of old, overgrown potted plants.
When you bring them back indoors during wintertime, always inspect for scale and remove any that you find immediately before they infest your entire collection!
Introduce Beneficial Insects
Another scale prevention method is to introduce beneficial insects like ladybugs or lacewings into your cactus garden, which will help attack and eat scale bugs whenever they try settling.
Beneficial scale insects like ladybugs and lacewings love scale bugs as a food source too, so they can be very helpful in ridding your garden of scale infestations naturally!
Scale on cactus plants is a common problem and one that can be easily remedied.
Remember to treat scale in the early stages, especially if you see ants crawling around your plant because scale often accompanies an ant infestation.
If scale gets out of control, it can lead to lost leaves, yellowing foliage, and eventually death for your prized succulent, so take action immediately!