White bugs are a problem for many gardeners who like to grow houseplants. There are several would-be plant bugs, but a common one is mealybugs on plants.
If you have discovered what looks like a white fuzzy coating on the stems and leaves of your succulents or other indoor plants, it is likely that you have a mealybug infestation.
The cottony white coating of mealybugs makes it easy to identify them. In northern climates, they are often seen on houseplants and in greenhouses.
Signs of a mealybug infestation are a white cotton-like substance on the plants, sticky amber colored honeydew, ants around your plants, or a layer of black “soot” on the foliage.
In warmer zones, they can be a problem both indoors and out. Keep reading to find out more about this pest and learn tips for mealybug treatment.
What are mealybugs?
Mealybugs (Hemiptera: Pseudococcidae) are a classic indoor pest. They are easy to spot since they are slow-moving and look like tiny fuzzy pieces of cotton wool.
Their powdery wax exterior is secreted as a protective coating. Mealybugs live by sucking plant sap.
These oval-shaped, small white insects on plants are related to scale, but they have soft bodies instead of the hard shells that scale has.
Mealybugs also secrete honeydew, which is attractive to ants and can cause black sooty mold.
You will normally find mealybugs at the leaf axils and nodes of plants. The soft bodies of the insects are easy to mistake for a fungus on your plants.
They measure 0.05” to 0.2” (1.2 – 5 mm) in size. I often discover these bugs when I am in the process of repotting a succulent and doing a routine inspection.
Mealybugs also like to hang out in clusters in inaccessible parts of the plant such as between the flowers, around twining stems, and some even live in the roots of plants. They can easily spread to nearby plants.
If you have mealybugs on your plants, it is likely they are female pests. Males are rarely seen on plants.
The white cottony coating is where the female hides her eggs.
Females can lay from 300 to 600 eggs. Mealybug eggs only take about 10 days to hatch, so your number of mealybugs can become large in just a few weeks.
Populations of mealybugs can overlap, so the infestation can multiply quickly.
Since they are so small, many gardeners do not even notice the mealybugs on plants until there are many present.
If you have a mealybug infestation, the plant will become stunted, the leaves will yellow and wither and drop. If left untreated, mealybugs can enough damage to kill the plant.
One of the most common gardening mistakes is forgetting to inspect for insects. Don’t let that be your downfall!
Mealybugs can infest many different species of indoor and outdoor plants. Some plants that they seem to be attracted to are these:
- jade plants
- citrus trees
- and many more!
When do mealybugs strike
You can find mealybugs on plants any time of the year. They seem to be more of a problem in late summer and fall.
What causes mealybugs?
There are several ways that mealybugs will find their way onto your plants. The most common ones are:
- Using soil that is contaminated
- Introducing and infected plant into your collection
- Re-introducing infected plants that lived outside during the summer
- Fresh flowers placed nearby which have mealybugs on them
- Occasionally, ants will bring mealybugs to your houseplants so they can feed off their honeydew
Mealybugs tend to be drawn to certain plants that have an abundance of the juices on which they like to feed. Citrus trees are particularly susceptible, as are some types of succulents and African violets.
Mealybugs are attracted to plants with high nitrogen levels and soft growth; they may appear if you overwater and over-fertilize your plants.
Controlling mealybugs can be a challenge, since the waxy coating helps to repeal most pesticides. That white, sticky stuff on your indoor plants means that you’ve got plant bugs.
Unfortunately, the white, waxy coating also repels most pesticides making it difficult to treat a mealybug infestation.
It is important to begin mealybug treatment right away when you first notice the problem of these tiny white bugs on plants.
The first step is to quarantine the affected plant or plants so that the problem does not spread to other houseplants.
Depending on the severity of the infestation, getting rid of a mealybugs on houseplants can be a job, but it is possible! Here is how to control mealybugs naturally with insecticidal soaps and other natural techniques.
Wash the mealybugs away
If you have just a few mealybugs, a steady stream of water can dislodge them and get rid of the problem.
The easiest way to wash the plants is to take them outside and use a hose to spray the plant. This will help to remove the bugs as well as their sticky honeydew residue.
You may need to repeat this process.
Delicate plants may not like this water treatment so use this method of controlling mealybugs for a light infestation.
Swab mealybugs to remove them
Use a Q-tip or cotton puff soaked in rubbing alcohol and swab it directly on the mealybugs. The white fuzzy coating is alcohol-soluble wax, so direct application of alcohol works better than plain soap and water.
Be sure the alcohol is no more than no more than 70% isopropyl alcohol. It’s also a good idea to test it on one leaf before you go whole hog with the entire plant.
In order for this method to work, the alcohol must come into direct contact with the mealybugs. Swab carefully, though, since delicate plants can be burned with alcohol.
As you swab the tiny white bugs be sure to inspect the plant carefully – under the leaves, at the leaf nodes, in the folds of the plant and at the base of the plant. These white bugs are good at hiding themselves!
Check your plants daily for signs that the mealybugs are still there. Repeat the alcohol treatment if you find them.
If you have a severe infestation, the plants should be washed completely in soap and water after the alcohol treatment, as well.
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Use Neem oil to kill mealybugs
Neem oil is a pesticide that occurs naturally in the seeds of the neem tree. It has a bitter taste, is brown and has a sulfur/garlic smell.
This oil will kill a variety of insects including mealybugs and is also helpful in treating fungal diseases in plants.
One of the benefits of using Neem oil is that it has a residual effect, so will kill bugs in future. Concentrated Neem oil is inexpensive and lasts a long time.
Some Neem oil contains other chemicals which can be harmful. Read your label and choose one that is cold-pressed raw or crude Neem oil.
If you are purchasing a pre-mixed spray instead of a concentrate choose a clarified hydrophobic Neem oil.
The concentrate is mixed with soap and water before treating mealybugs.
When properly applied, Neem oil controls a mealybug infestation with minimal risk to humans, and pets.
Insecticidal soap spray
There are commercial organic insecticidal soap sprays that will kill mealybugs. These sprays are made with potassium salts of fatty acids.
They are useful not only on mealybugs but also on common houseplant pests like aphids, whiteflies and spider mites. These soap sprays leave no nasty residue and are non-toxic to animals and birds.
When the soap is sprayed directly onto the foliage, it comes into contact with mealybugs and kills them. The soap spray may need to be re-applied until the infestation is gone.
Make your own mealybug insecticidal soap spray
You can use commercial products but a much more cost-efficient method of treating mealybugs is to make your own mealybugs spray. It’s easy to make with just a few ingredients.
Combine 1 cup of vegetable oil with 1 tablespoon of Dawn dishwashing detergent to make a “soap”, and mix 2 teaspoons of the mixture with a cup of warm water. Add to a spray bottle and treat for mealybugs.
You can print out the recipe in the project card at the bottom of this post.
The soap kills bugs on contact. Be sure to spray the whole plant, not just where mealybugs are visible. Spray the leaves, leaf nodes and stems near the soil.
Small plants can be treated in the sink to wash the leaves with the soap spray and then rinsed. You can treat larger plants in the shower.
Be sure to test the spray on a few leaves before treating the entire plant. Some types of soap can damage sensitive plants.
Remember that retail and homemade insecticidal soaps do not have a residual effect on the plants and they can come back. Spray regularly until you no longer see mealybugs.
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Tips for making sure mealybugs don’t return
Healthy, strong plants are less susceptible to mealybugs than weak, stressed plants.
While there is no true way to completely prevent mealybugs, there are some things that will lessen the chance of them returning.
Check new plants carefully
Mealybugs spread easily from one plant to another. Be sure to carefully inspect any new plants you bring into the house.
This goes for plants that have summered outdoors and are being brought in for the winter.
Lower the temperatures
If your plant can withstand lower temperatures, drop the nighttime temp to 60°F (15.5° C) will discourage mealybugs, since they like a more tropical temperature range.
Change the soil
Some mealybugs live in the soil of houseplants. If your plant seems to continually get attacked by the small white bugs on plants, you can change out the soil.
Remove the top few inches of soil and replace it with fresh potting soil.
Inspect the plant pots
Treatment for mealybugs in the ways outlined above will get rids of most bugs, but don’t just inspect the plant! Mealyugs can live on the sides and under plant pots.
After treating the plants with your preferred method, wipe down the pots with a isopropyl alcohol on a cotton ball to kill any bugs that may be hiding.
Clean the area where the plant has been sitting. It is amazing how these little pests will hide nearby.
Move your treated plant
After treating for mealybugs, move your plant to another spot where it is unlikely that bugs will be lurking.
Practice good plant maintenance to prevent mealybugs on plants
Be careful not to over-water or use too much fertilizer on your plants. Mealybugs are attracted to plants with a high level of nitrogen and lots of soft new growth.
Keep your foliage clean. Washing the leaves regularly will discourage future infestations.
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DIY Mealybug Insecticidal Soap Spray For Indoor Plan Pests
This DIY mealybugs insecticidal soap spray kills the little white bugs on plants immediately. Repeat the application for a large infestation. This homemade remedy is much more cost-effective than store bought products.
- 1 cup (240ml) of vegetable oil
- 1 tablespoon (15ml) of Dawn dishwashing detergent
- 1 cup (240ml) of warm water
- Large container
- Spray bottle
- Combine 1 cup (240ml) of vegetable oil with 1 tablespoon (15ml) of Dawn detergent.
- Mix well do to make a "soap."
- Combine 2 teaspoons (10ml) of the soap mixture with 1 cup (240ml) of warm water.
- Stir well.
- Pour the soap/water mixture into a spray bottle and treat for mealybugs.
- Spray the whole plant, not just where mealybugs are visible. Spray the leaves, leaf nodes and stems near the soil.
- Small plants can be treated in a sink and rinsed. Use a shower for larger plants.
- Repeat as needed until mealybugs are gone.
Sunday 4th of December 2022
If you spray the soap straight onto the plants, the mealybugs will be killed on contact. Sometimes further applications of the soap spray are needed to completely eliminate an infestation.