MealyBug: All You Need to Know for Effective Pest Control

Mealybugs are common pests that can wreak havoc on various plants, both indoors and outdoors. These soft, oval, wax-covered insects tend to feed on many plants found in garden, landscape, and indoor settings, making them a problematic presence for plant enthusiasts 1. Often found in colonies, the insects are closely related to soft scales and have piercing-sucking mouthparts, which allow them to extract nutrients from their host plants 1.

A telltale sign of a mealybug infestation is the presence of white, waxy, cottony material covering the bugs to protect them from excessive heat and moisture loss 2. Some species of mealybugs even feed on plant roots, making them challenging to detect and eliminate 1. With their potential to cause serious damage to various plants, it’s crucial to understand how to identify and manage these unwanted pests effectively.

Understanding Mealybugs

Pseudococcidae Family

Mealybugs belong to the Pseudococcidae family of scale insects. They are known for:

• Sucking on plant sap
• Injecting plant toxins
• Producing honeydew
• Causing growth of sooty mold¹

Life Cycle

The life cycle of mealybugs consists of three stages²:

1. Egg
2. Nymph
3. Adult

Females typically lay clusters of eggs in white waxy enclosures, called ovisacs. Nymphs (also called crawlers) hatch from the eggs and begin feeding on plant sap. As they grow, they shed their exoskeleton multiple times before becoming adults.

Types of Mealybugs

There are several types of mealybugs, including:

• Citrus mealybugs³: Most common greenhouse species, can cause significant damage to plants
• Longtailed mealybugs⁴: Characterized by long tail filaments, about twice the body length
• Madeira mealybugs⁵: Grayish, oval-shaped insects with three parallel rows of small waxy tufts

Comparison Table

Identifying Mealybug Infestations

Appearance

Mealybugs are soft, oval, wax-covered insects with a characteristic white, cottony appearance. They typically have a powdery wax coating with some having waxy tufts around the body and several tails at the rear end.

Common Signs

• Honeydew: Mealybugs feed on plant sap, producing a sticky fluid called honeydew
• Sooty Mold: Black fungus, called sooty mold, often grows on honeydew, making leaves look dirty and reducing photosynthesis
• Reduced Plant Vigor: Heavy infestations can stunt growth and affect plant health

Affected Plants

Mealybugs infest a variety of plants, including:

• Indoor houseplants
• Garden and landscape plants
• Tropical foliage plants in particular

Here’s a comparison of some common plants affected by mealybugs:

Mealybug Damage and Effects

Direct Damage

Mealybugs are sap-sucking insects that cause direct damage to plants by feeding on their sap. These pests inject their feeding tubes into plant tissues, such as roots and stems, draining the plants’ nutrients and water. This results in:

• Wilting
• Stunted growth

For example, grapes and indoor plants like foliage plants can be severely affected by mealybug infestations.

Indirect Damage

Apart from the direct damage, mealybugs can also cause indirect harm to plants. As they feed on the sap, they excrete a sticky substance called honeydew, which can lead to:

• Sooty mold growth
• Ant infestations

Here’s a comparison table displaying the differences between direct and indirect damage:

Mealybugs form colonies under leaves and on plant stems, which makes them difficult to control. They are often covered in a powdery wax that provides protection against some pesticides. Moreover, their tiny, mobile crawlers can easily spread to new plants.

To manage mealybug infestations, it is important to detect them early and act promptly. Some of the pros and cons of using pesticides include:

Pros:

• Effective in controlling mealybug populations
• Can prevent further outbreaks when applied at the right time

Cons:

• May harm beneficial insects
• Some mealybugs may be resistant to certain pesticides

A combination of early detection, proper plant management, and targeted pesticide application can help prevent mealybug damage and maintain healthy plants both indoors and outdoors.

Preventing Mealybug Infestations

Roles of Ants and Aphids

Ants and aphids play a significant role in mealybug infestations. Ants protect mealybugs from predators, while mealybugs produce honeydew, a sweet substance ants feed on. To control infestations:

• Manage ants in the area
• Use beneficial insects to control aphids

Use of Nitrogen Fertilizers

High levels of nitrogen fertilizers can lead to mealybug infestations, as these pests prefer plants with abundant nitrogen. To prevent infestations:

• Use slow-release or low-nitrogen fertilizers
• Monitor plants for signs of overfertilization

Quarantining New Plants

To prevent mealybugs from spreading to other plants:

• Quarantine new plants for 2-3 weeks
• Inspect for any signs of mealybugs or other pests

Maintaining Cleanliness

Cleaning plays a crucial role in preventing infestations. Some tips are:

• Remove dead leaves and debris
• Avoid using leaf shine or other materials that can harbor pests

Regular Inspection and Pruning

Inspect your plants regularly and prune them to:

• Remove damaged or infected parts
• Allow proper airflow and light penetration

Remember to sterilize your tools to prevent spreading pests.

Mealybug Control Methods

Natural Remedies

One effective natural remedy to control mealybugs is using isopropyl alcohol. You can dab a cotton swab or a small paintbrush in 70% isopropyl alcohol (rubbing alcohol) and directly apply it to the mealybugs. This method works best when there’s a small infestation.

Another option is using predatory insects such as ladybugs and lacewings, which are natural predators of mealybugs. They can help reduce the mealybug population on your plants.

Chemical Solutions

For more extensive infestations, you might need chemical solutions like insecticidal soap or neem oil. These can be directly sprayed onto the mealybugs, and you need to make sure to cover all plant surfaces. These options are relatively safe for beneficial insects.

• Pros of insecticidal soap and neem oil:
  • Safe for beneficial insects
  • Effective in controlling mealybugs
• Cons of insecticidal soap and neem oil:
  • May require multiple applications
  • Can harm sensitive plants

When natural remedies and insecticidal soap or neem oil are not effective, systemic insecticides such as imidacloprid can be used. These insecticides are absorbed by the plant and can control the mealybugs more effectively.

Comparison of chemical solutions:

Remember to always follow the product label instructions and apply the right amount to minimize potential harm to your plants and beneficial insects.

Managing Mealybugs on Specific Crops

Mango

To manage mealybugs on mango trees, it is essential to:

• Monitor the trees regularly for signs of infestation
• Use natural predators like ladybird beetles

An integrated pest management approach is recommended. High-pressure water sprays can dislodge mealybugs from trees, while insecticides should be used cautiously to avoid harming beneficial insects.

Sugarcane

In sugarcane crops, mealybug management strategies include:

• Regular inspection for infestations
• Biological control agents, such as parasitic wasps

Chemical control is an option but can harm natural predators. Always opt for targeted insecticides to minimize the impact on other organisms.

Pineapple

Pineapple crops can be protected from mealybugs by:

• Proper irrigation management to reduce moisture, since damp conditions promote infestation
• Encouraging the presence of natural enemies, like lacewing larvae

Applying targeted insecticides and cultural practices, such as cleaning and proper disposal of infested plant parts, can also offer help.

Coffee

To control mealybugs in coffee plants:

• Regularly inspect plants and remove any infected berries
• Introduce biological controls like predatory beetles

Crop diversification and appropriate pruning can help reduce the chances of mealybug infestation in coffee crops, as well.

Papaya

In papaya crops, mealybug infestations can be managed by:

• Providing adequate spacing between plants
• Introduction of parasitic wasps for biological control

Targeted insecticides should only be used when necessary, and other cultural practices, such as sanitation and the removal of infested plant parts, can help limit mealybug damage.

Special Cases

Ground Mealybugs and Roots

Ground mealybugs are a type of mealybug that infest the roots of plants. They cause damage by feeding on the plant’s root system, leading to stunted growth and a decline in overall health.

• Common signs of ground mealybug infestation include yellowing leaves and wilting.
• Use of systemic insecticides may help in controlling these pests.

Hibiscus Mealybugs and Succulents

Hibiscus mealybugs are a damaging pest known to specifically target hibiscus plants and succulents.

• Infestations result in discolored leaves, stunted growth, and distorted flowers.
• To control these pests, introducing beneficial predators like ladybugs can be helpful.

Comparison Table

Longtailed and Madeira Mealybugs

Longtailed and Madeira mealybugs are two other unique species of mealybugs, causing significant damage to a wide range of plants.

• Longtailed mealybugs have elongated tails, while Madeira mealybugs are distinguished by a dark stripe on their back.
• Both species can be controlled through the use of insecticides and introducing beneficial predators.

In summary, mealybugs come in various types that infest different plants. Understanding their unique characteristics can help in controlling their damaging effects on our plants.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Giant Snowball Mealybug from Australia

Subject: Found at work
Location: Victoria, Melbourne
May 22, 2013 8:39 pm
Hi, just wondering if anyone knows what this is please?
Signature: Kim

Hi Kim,
The first time we received a photo of a Snowball Large Mealybug in the genus Monophlebulus, we had no idea what it was as it looked so very primitive, and Eric Eaton eventually identified it as a Giant Scale Insect.  Several years later when we received another photo, we learned that the Snow Ball Large Mealybug in the genus Monophlebulus at which time Karl who frequently contributes to our site did some wonderful research.  There is a nice photo on Life Unseen and the Brisbane Insect Website has some marvelous photo of members of this genus with the white cottony covering found on so immature Hemipterans.  We have taken the liberty of making the grammatically confusing common name more acceptable by using the compound word and moving the adjective in front of the noun:  Giant Snowball Mealybug has a much better ring to it.  As Karl noted in the previous posting, Ground Pearl is a name for the encysted nymph that is noted on the North Carolina Cooperative Extension Department of Entomology Ornamentals and Turf page.  

Letter 2 – Bird of Paradise Fly from Australia

Subject: Fly with plumes
Location: North Sydney, Australia
June 6, 2017 9:18 pm
Hi!
A colleague sent me a picture of this insect she found. Whilst my first thought was that some unfortunate insect had met its end by Cordyceps, I was told it was definitely alive.
I presume therefore this is a male specimen of some species, but I don’t know where to start to id this.
Could you help me? Thanks!
Signature: Fe

Dear Fe,
This is a male Mealybug, sometimes called a Bird of Paradise Fly, a statement we verified on the Brisbane Insect site, where it states:  “As a member in the Mealy Bugs family, Bird of Paradise Fly is unbelievable large. Females grow up to 40mm, the largest in Soft Bug suborder. Bird of Paradise Fly is an incredible insect. It Adult males have only one pair of wings. When we first it we thought it could be a fly in order Diptera. After we saw the female and we were confused. We cannot tell even the order of this insect. More information and pictures on Bird of Paradise Fly please click this page. “

Letter 3 – Mealy Bugs

bugs infesting my Emina fern
Dear Bugman,
I live in southern California and I noticed a bunch of these little bugs
on my emina fern, I was wondering if you could tell me what they are and
if they are harmful to my plants. They have a lot of little legs, the
antennae stick out of their back end, and they’re about the size of the
tilde sign on the keyboard.
Thanks,
Tom

Hi Tom,
You have Mealy Bugs which will infest many types of house plants. Check with a local nursery about the best way to get rid of them.

Letter 4 – Mealybug

Unidentified Rosemary Bug
July 31, 2009
I found this bug all over my rosemary plant. It doesn’t appear to be harming the plant yet. Could you identify this bug? How would you suggest ridding the plant of this bug?
Best Regards, Brian Jennings
Fraser, Mi, USA

Hi Brian,
This is a Mealybug, and it is a common plant pest related to Scale Insects found in the garden, in the greenhouse, and on houseplants.  There are several genera and species of Mealybugs, and we believe you may have the Citrus Mealybug, Planococcus citri, a common species known to infest rosemary.  Now that you know what you have, you should be able to locate numerous online sources to help you control the Mealybugs.  We have been unable to log onto BugGuide since yesterday, but we found a University of Wisconsin Master Gardener page on Mealybugs with much helpful information.

Letter 5 – Mealybug

Subject: Daniel – Strange White Bug
Location: Hawthorne, CA
February 2, 2013 10:15 pm
Hi Daniel,
I’m pretty sure the little fat dark things in this photo are aphids, but cannot figure out what the white bug is. Can you please help?
Signature: Thanks, Anna Carreon

Hi Anna,
We cannot make out details in the black bugs to confirm if they are Aphids, but we do know that the white bug is a Mealybug, a common pest on a broad variety of plants.  You can find numerous images of Mealybugs on BugGuide and the University of Minnesota Entomology website has a nice page on them as well.  You should try to get rid of them while there are only a few.

Hi Daniel,
Well, I certainly should have known that.  Thanks very much and I’ll go out and take care of that this morning!
Anna

Letter 6 – Mealybug

Subject:  Termite?
Geographic location of the bug:  Anaheim California
Date: 04/01/2020
Time: 08:01 PM EDT
Your letter to the bugman:  I took this picture March 25, 2020 not sure what that bug is,
Hopefully someone can tell me.
How you want your letter signed:  Ken O

Dear Ken,
We are relatively certain this is a Mealybug based on this BugGuide image.  According to the University of Wisconsin Master Gardener Program:  “The citrus mealybug (Planococcus citri) is the most common species found on plant foliage. It feeds on a wide variety of plants, and especially likes soft-stemmed and succulent plants such as coleus, fuchsia, croton, jade, poinsettia and cactus. In my greenhouse I also find them consistently on rosemary, citrus, and bird of paradise. ”  You did not indicate where you found it.