How Do You Get Rid Of White Fungus On Cactus

We apologize, but Mr. Smarty Plants needs some time to catch up after receiving an overwhelming amount of mail. Soon, we hope to be taking new inquiries once more. I’m grateful.


Before, Mr. Smarty Plants responded to a query regarding cholla cactus cochineal bug management (similar to your prickly pears). What Larry and Brigid Larson wrote is as follows: Cochineal feeding can harm the cactus and occasionally result in the host plant’s death. The Cactus Doctor talks about getting rid of cochineal. Their advice is as follows: 1) A hose with a power nozzle attached to the end. 2) It was advised to clean the affected areas with insecticidal soap or unscented dish soap to treat them if the infestation gets out of hand. Neem oil was also mentioned as a possible natural remedy.

In response to another Mr. Smarty Plants query about cochineal bugs on prickly pear cactus, Nan Hampton provided the following response. (As you can see, this is a common query.) It sounds like cochineal bugs are infesting your cactus (Dactylopius sp.). They are cactus-eating small scale insects. They generate fluffy white wax that covers their body as they consume the cactus and shields them from predators as well as the weather (especially drying out). The fluffy wax also acts as a sail or balloon to carry the bugs to a fresh cactus patch in the breeze. The carminic acid that the bugs create aids in shielding them from predators, particularly ants. Indigenous peoples of southwestern North America, Central America, and subtropical South America have been using this bug’s carminic acid for centuries—possibly millennia—to synthesize a vivid red dye that they utilized to create exquisitely colored fabrics. Cochineal bugs were formerly only found in the New World. The cochineal bug spread around the world when European explorers came to a place and saw the stunning red cloth made by the locals. Although they have also been employed to help reduce cactus populations, the need for cochineal bugs decreased when a synthetic red color was created. But recently, there has been a resurgence of interest in cochineal bug cultivation for red dye because it was discovered that synthetic red dyes can have harmful side effects on health. Today, food coloring and cosmetics both employ the bug-derived dye. Because of this, managing cochineal bugs hasn’t really been a top concern, and as a result, I haven’t been able to discover a lot of information on managing them. If you only have a minor infestation, I advise scraping them off (slowly, to avoid the cactus spines) and throwing them away. They might also come off with a water under pressure wash. To ensure that you don’t harm your cactus, test a tiny area first. Then, collect and get rid of any insects that you wash off the cactus.

The University of Arizona Extension also suggests a similar set of remedies in a publication on cactus diseases.

The usage of insecticides was discussed on multiple websites, and Wikipedia included several natural predators: “The population of the bug on its cacti hosts can be lowered by a variety of natural enemies. Insects appear to be the most significant group of predators. Numerous parasitic wasps as well as predatory insects including ladybugs (Coleoptera), different Diptera (like Syrphidae and Chamaemyiidae), lacewings (Neuroptera), and ants (order Hymenoptera) as well as pyralid moths (order Lepidoptera), which kill cacti, have all been identified.”

Here is more information on the intriguing world of the Dactylopius coccus cochineal scale insect and the carmine dye that was highly sought for fabric dyeing in the 15th century.

How do I remove the white substance from my cactus?

White fuzz on cactus can hinder their growth and lessen their visual attractiveness. What then creates the white fuzz on cacti, and how may mealybugs be removed from cactus plants?

Pour rubbing alcohol into a garden spray bottle after combining water and rubbing alcohol in a 1:3 ratio. To get rid of the bugs, spray all the cactus that are covered with white fuzz. You might also add ladybugs to your cactus to eat the mealybugs and get rid of the white fuzz on the plants.

I’ve used the Bazos ladybugs on my plants, and they work incredibly well at organically removing mealybugs and other damaging pests like aphids. You can use them if you don’t want to use pesticides on your indoor plants and outdoor gardens.

Method #1: Cut Off The Infected Area

To start, use a sterilized knife or pair of clippers to remove any patches of fungus on the cactus plants.

Then, depending on the fungicide you use, treat those healthy areas once every two weeks for six to twelve months.

Follow the directions on the fertilizer container to fertilize your plant as necessary to encourage development and stop further disease outbreaks.

Additionally, make sure that it receives consistent watering throughout this time and try to avoid letting it become completely dry in between waterings since too much moisture may result in black patches in addition to root rot issues!

Method #2: Use Baking Soda and Hydrogen Peroxide

Making a solution of baking soda (sodium bicarbonate) is one of the most used techniques.

Pour two teaspoons into an empty spray bottle along with one quart of warm water.

Whenever you notice any indications or symptoms, such as leaf spot, that fungus on cactus plants has resumed its attack, spray your cactus plants well until they are completely moist, including the undersides and tops of leaves.

For six weeks straight, you should perform this procedure at least twice a week to completely eradicate the fungus on your cactus plants.

Method #3: Make Your Own Fungicide Solution

In an empty spray container, combine one tablespoon of liquid soap, hydrogen peroxide, and baking soda with one gallon of water.

To totally get rid of fungus on cactus plants, spray it abundantly onto your plants every two weeks for at least six months!

Method #4: Spray With White Vinegar Solution

Another choice is to carefully dip the leaves into a solution of one part white vinegar (or apple cider vinegar) to four parts water in an empty plastic bucket or container. Do this until the leaves are completely moistened but not dripping wet.

The fungicide that has remained on the surface should be allowed to dry naturally rather than being rinsed off because doing so will only remove around half of it. It is therefore better to leave it alone.

This remedy must be used within a week if it is homemade. If you purchase it, be sure to keep it in a dry, cold environment.

Method #5: Clean Your Cactus Plant Thoroughly With Soap and Water

The easiest option is to just give your cactus plant a thorough washing every day, or at least every other day, with soap and water, especially after working near them while they are dusty.

Before applying fungicide using method number three above, make sure to clean up any dust since it acts as an insulator to prevent fungi from drying out.

Spray two quarts of lukewarm water with one tablespoon each of liquid soap, hydrogen peroxide, and baking soda to clean all leaves, including the undersides.

Method #6: Use a Fungicide Solution

Fungicides can be used to treat your cactus plant if it develops a fungus infestation.

Fungicides come in a variety of forms, some of which function better than others and serve distinct needs. Be careful to pick the proper one for your situation!

Keep in mind that even if just one or two leaves exhibit symptoms, it is still crucial to spray them down because, if left untreated, this disease will soon spread throughout the entire plant.

Why does the white substance on my cactus exist?

White spots on cacti are typically brought on by an insect infestation. Mealybug or scale shields can be seen as the white patches. White spots on cacti can also be caused by fungus development brought on by necrotic spot virus or powdery mildew. Treat white spots as soon as you notice them and have determined their cause because, frequently, yellowing and aberrant foliage appear after white spots appear.

Why is my cactus covered in mold?

In contrast to other species, this mold, which is brought on by the fungus Drechslera cactivorum, can completely obliterate a plant in as little as four days. The illness begins as yellow spots that quickly become brown and spread, depriving the cactus of water and covering it in spores that are a dark brown color.

Will alcohol work on my cactus?

Spray the plant with some isopropyl alcohol that is 91%. That will instantly kill them. Don’t hesitate – do it now. Rubbish alcohol is too oily to use.

How does fungus appear on a cactus?

Only the enormous variety of fungi can outcompete the great number of cacti species. Cactus pads frequently develop fungus spots, such as the Phyllosticta pad spot. Since treatments are typically the same, it is frequently irrelevant to identify the specific fungus that is causing the spots.

Once their visible harm is noticed, some fungal kinds attack the roots and finally the entire plant, therefore it is too late for the plant. Simple topical fungal spots are much easier to treat and, as long as the offending fungus is controlled, usually do not pose a threat to the cactus’ existence.

Cacti lesions can appear in a variety of ways. They could be square, oblong, angular, elevated, flat, or any other shape. Many are discolored, but once more, the hues might be anywhere from yellow to brown to completely black. Some are snarky, some are tearful. These may exude rust-colored, brown, or black fluid as a sign of a serious illness.

Opuntia and Agave cacti are the most frequently affected by fungal infections. Water spots or light discolorations on the plant’s epidermis are frequently the first signs of fungal diseases on cacti. As the fungus develop and spread over time, the symptoms may become more severe and may even eat into the cambium as a result of the surface skin breaches that allow the infection to enter.

Make your own fungicide spray at home.

You have control over the materials when you learn how to manufacture your own fungicide, many of which are already in your house. Here are some of the more widely used ingredients for creating fungicide for gardens and lawns:

  • In a gallon (4 L) of water, add 4 teaspoons or 1 heaping tablespoon (20 mL) of baking soda (Note: many resources recommend using potassium bicarbonate as a substitute for baking soda.).
  • For homemade plant fungicide, dishwashing soap is a common item that doesn’t contain bleach or degreaser.
  • To make homemade plant fungicide stick to leaves and stems, cooking oils are frequently added.
  • A common ingredient in commercial plant fungicides is pyrethrin, which is found in the leaves of the painted daisy flower. You may grow your own painted daisies and use the flowers to protect your plants from fungus. Flower heads should be dried before being ground or left to soak in 1/8 cup (29.5 mL) of alcohol overnight. Add up to 4 gallons (15 L) of water, combine, and then filter through cheesecloth.
  • Some bacterial and fungal illnesses can be controlled by using a Bordeaux combination during the dormant season. You can create your own Bordeaux mixture using copper sulfate powder and pulverized limestone. 4-4-50 is the suggested strength for application during dormancy. With 50 gallons (189 L) of water, combine 4 parts of each. Reduce the recipe for this homemade plant fungicide to 6.5 to 8 teaspoons (32–39 mL) of copper sulfate and 3 tablespoons (44 mL) of limestone to 1 pint (.5 L) of water if you only need a smaller amount, such as for a gallon.

How should a cactus be cleaned?

To get between those spines and remove cobwebs and dust, use a soft brush. To clean your cacti of dust and cobwebs, use a variety of brushes, such as makeup brushes or artist brushes.

My plants: Will rubbing alcohol harm them?

If rubbing alcohol is used as a pesticide or herbicide in excessive doses or if the plant is sensitive to alcohol, it can harm plants. Avoid using alcohol on plants like hydrangeas, mint, and lavender that quickly absorb moisture and pollutants through their leaves.

Rubbish alcohol works better as a pesticide on plants with waxy surfaces on their leaves and stems, such as peace lilies and monsteras.

Rub alcohol harms succulent plants?

Neem oil, insecticidal soaps, rubbing alcohol in a spray bottle, or cleaning the infected regions with water can all be used to control them. The bugs are promptly killed by a fine, light spray of rubbing alcohol that doesn’t harm succulent foliage.

How can a sick cactus be saved?

While skin-deep disorders in the upper body of the cactus can be easily handled, those that have spread to the roots typically result in a plant that is slowly dying. Excision of the diseased tissue works successfully for the majority of cacti. Dig out the damaged flesh with a clean, sharp knife, then let the hole dry out. When the wound is healing, avoid overhead watering.

There is not much you can do if the roots have been affected by the harm. You could attempt to repot the plant by removing the unhealthy soil and adding sterile soil in its place. Before replotting the roots in a new potting medium, thoroughly wash the roots out.

Taking cuttings and allowing them to grow roots for a brand-new plant is another way to salvage a mushy, soft cactus. Before inserting the cutting into the sand, let it a few days to callus over. The cutting may need to be rooted for several weeks. A healthy cactus that looks exactly like the parent plant will be created using this method of propagation.