Mealybugs: How To Get Rid of Those Fluffy White Bugs on Cannabis

Last updated: 23 June 2021

How To Get Rid of Mealybugs

Growing cannabis comes with many challenges, especially when you’re trying to grow quality bud. One of the biggest problems every grower will face from time to time is the presence of harmful parasites and mold. At the forefront of troublesome pests is a fluffy, cotton wool-looking parasite called a mealybug.

These tiny but potentially deadly white fuzzy bugs can destroy your plants and lower your overall yield size and quality. Thankfully, monitoring your plants for mealybugs is easy, and there are many great ways to get rid of these nasty buggers.

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What are Mealybugs?

The first step to getting ahead of mealybugs is learning to identify them at the early stages before the damage caused is irreversible.

Identifying Mealybugs

If your plant has mealybugs residing on its leaves or stems, you will notice the accumulation of a white cottony substance that may be mistaken for mold, and will also see tiny white crawling bugs.

These white fluffy bugs, scientifically known as Planococcus citri, are no bigger than 1cm (0.4”) in size, with an oval, scaled body covered in hairs. These cannabis bugs secrete honeydew and gather along the stems and crevices of plants.

Females are the most obvious, as they are larger than males and tend to stick around eating, laying eggs, and spreading the white cotton-like substance. Males, who don’t live very long after reproducing, are much smaller and have wings.

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Why are Mealybugs Dangerous to Pot Plants?

Any sign of mealybugs should be taken seriously to save your plants and allow their buds to develop. Mealybugs live on the sap of marijuana plants, with females latching on and covering themselves in a protective layer while they feast.

A long-term infestation with a high number of these white fuzzy bugs can ultimately lead to lower photosynthesis, causing the loss of bud quality or even the death of your plant entirely. Check your plants for any signs of mealybugs regularly to ensure treatment can be applied in time.

Symptoms and Signs of Mealybugs on Cannabis

Along with the appearance of the white fuzzy bugs on marijuana plants, there are a few additional signs of mealybugs you should watch out for:

  • Ants or other insects are drawn to your plants: Ants can live symbiotically with mealybugs, offering them protection from predatory insects while surviving off their honeydew. Ants can also attract mealybugs.
  • The formation of mold and mildew: In humid climates, the honeydew left behind by mealybugs, paired with the bite wounds from the insects, increases the chances of mold formation.
  • Discolored or dying leaves: Mealybugs can drink enough sap and cause enough mold to inhibit the photosynthesis of affected leaves.

Noticing any of these symptoms should be cause for concern, but thankfully, there are plenty of things you can try before sacking your plants altogether.

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How to Get Rid of Mealybugs on Weed

Mealybugs have a hard protective outer layer, along with the protective web-like substance that they secrete and cover themselves with. To get rid of these pests, you’ll need to try either removing the bugs physically or weakening them enough so that they die off themselves. Luckily, there are a couple of effective ways to do this.

Remove as Many Mealybugs as Possible Manually

Whether your infestation of mealybugs is mild or severe, you can start by simply manually removing as many of these white fluffy bugs as possible. Fill a bucket with soapy water and use a damp cloth to detach the mealybugs, throwing them into the water to kill them.

You can also use a cloth soaked in diluted alcohol for quicker action or carefully pressure-spray your pot plant to loosen and blast the bugs off.

Apply a Neem Oil Solution

Neem oil is a highly effective natural treatment for a wide variety of parasites and mold, including the treatment of mealybugs. Use it alongside potassium soap for best results.

For the most effective solution, mix 1 teaspoon of neem oil, 1 liter (35oz) of warm water, and ⅓ teaspoon of non-toxic detergent in a mister or pressure spray bottle. Mist your plant with the solution every 3 days, taking care not to spray any of your buds. Neem oil can leave an unpleasant taste on buds and may be harmful to ingest, so use it during the vegetation stage only.

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Use Insecticidal Soaps

Another highly effective solution for a mealybug infestation is insecticidal soap. These soaps contain fatty acid salts that weaken the outer shell of insects without negatively affecting your plants. They don’t leave residue behind, but do require frequent reapplication to successfully keep the bugs at bay.

Use Insecticidal Soaps to Get Rid of Mealybugs

Bear in mind that despite being safe to use, it’s best to avoid getting any of the solution on your plant’s buds.

Spray or Dab with Rubbing Alcohol

A great way to kill mealybugs is with the direct application of isopropyl alcohol to their outer shells. Alcohol dries out the white fuzzy bugs’ protective layer, ultimately weakening and killing them. Depending on the size of your plant, there are two ways to apply alcohol to the bugs.

On larger plants with a large number of bugs, you can mix a solution of 1 part rubbing alcohol to 9 parts water and spray the bugs directly once a week until they’re all gone. For smaller plants, you can use a cotton swab soaked in rubbing alcohol to apply directly to the mealybugs.

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Sprinkle Diatomaceous Earth on Your Soil

Diatomaceous earth is a 100% natural pest detergent made up of fossilized shells. Although safe for humans and animals, at a microscopic level, the dust proves dangerous to insects with its sharp particles, causing fatal puncture wounds to their exoskeletons and lodging in the joints of insects like mealybugs.

Sprinkle Diatomaceous Earth on Your Soil

To use diatomaceous earth as a pest detergent, sprinkle it across the soil beneath your plants, stopping insects from making their way up the plants’ stalks.

Release Predatory Bugs

To keep things within the natural circle of life, predatory bugs that love to feast on smaller prey like mealybugs can be a great addition to your pest-repellent techniques.

The best insect to introduce are ladybugs, particularly the Cryptolaemus Montrouzieri species. These ladybugs can sustain themselves on mealybugs, but make sure not to spray any insect detergents on the plants once they’re introduced or you risk killing them as well.

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Spray This Simple Home-Made Solution

Lastly, you can also make a homemade solution of simple, easy-to-find ingredients that will effectively deter the bugs on cannabis. Here’s the basic recipe for homemade bug detergent:

  • 5 tablespoons castile soap (undiluted)
  • 2 tablespoons olive oil
  • 3.5 liters (8oz) water
  • 1 teaspoon garlic (powdered is best)
  • 1 teaspoon ground red pepper

Spray This Simple Home-Made Solution

Reapply this spray weekly until you reach the desired results.

PRO-TIP: When it comes to using sprays on your cannabis plants, whether store-bought or home-made, make sure to apply them in the evening or at night in order to prevent burns on the plants’ surfaces from the hot sun.

How to Prevent Mealybugs on Cannabis

If you don’t have mealybugs on your cannabis plants yet, there’s no harm in preventing the white fuzzy bugs in the first place. Mealybugs love colder temperatures and humidity, so here are the best ways to prevent them and other pests from invading your plants:

  • Check your plants for bugs daily
  • Make sure there’s good airflow and ventilation where your plants are growing
  • Keep your humidity below 65%
  • Monitor temperatures and try to keep within the 20-25°C range
  • Clean up around your plant regularly, removing dead plant matter
  • Keep an eye out for honeydew or ants
  • Spray your plants with neem oil during the vegetative stage

Mealybugs on Your Weed? Don’t Panic, You’ve Got This!

As you can see, although finding a bunch of sap-sucking bugs infesting your plants may send you into a wild panic, there are many great solutions to the problem and preventative measures you can take for future plants. All you can do is try one thing at a time until the mealybugs are down to a manageable level. Then, enjoy watching your plant thrive, bug-free!

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Evan Reilly
Use beneficial bugs, ladybugs, eat aphids and mealy bugs 🐞💪
Moses Free
I'm dealing with this now on my plant. They kept coming back like crazy. It wasn't until I turned over the pots and underneath the saucer until I rid myself of those little bastards!
Mike Arredondo
Those freaking mealy bugs are the worst. They annihilated my grow once. They destroyed my poor girl. I am still not over it and its been about a year. I had no idea that I could use neem oil against them. Thank you!
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