How To Get Rid Of Mealybugs, According To An Expert

Mealybugs can affect all types of crops, ornamentals, and houseplants, including succulents and cacti. Outdoors, mealybugs have natural predators to keep their numbers in check. But indoors in your nice, cozy house, their numbers can increase quickly.

Unfortunately, these tiny insects are difficult to manage, especially if you don’t catch them early. “Mealybugs are little vampires.,” says Alejandro Del-Pozo, PhD, assistant professor and extension specialist at Virginia Polytechnic Institute and State University. “They use their piercing-sucking mouthparts to feed on plant cells and eventually can kill the plant.”

Mealybugs have a distinctive appearance. They are elliptical, flattened insects covered with a white, waxy or fuzzy-looking material that serves as protection. Some species also have long filaments that extend from their posterior ends. Mealybugs often are confused with scale, a related pest that also hides under a waxy protective coating. But scale pests don’t move around, and mealybugs do, says Del-Pozo. 

How To Get Rid of Mealybugs

If you’ve identified mealybugs on a houseplant, try these steps for control:

• Isolate the affected plant from your other houseplants.
• Act fast. When you discover an infestation, treat right away. “The bigger mealybugs get, the thicker the waxy coating gets, and the more difficult they are to control,” says Del-Pozo.
• Scrub them off with a cotton swab dipped in alcohol. But test a small area on your plant first, and wait 48 hours to ensure the alcohol won’t harm the plant, says Del-Pozo. This method is only recommended for small infestations.
• Use an insecticidal soap or horticultural oil, such as neem oil. Again, test the product first because some plants are more sensitive to products, says Del-Pozo. Be sure to spray all surfaces, including leaves, crevices, and stems, for good coverage because these are contact insecticides that must coat the insect thoroughly in order to be effective.
• If you’re still battling an infestation, try an insecticide labeled for houseplants. These usually contain botanical pyrethrins. Read the label to ensure the product is effective on mealybugs and safe to use on houseplants, and follow the instructions.
• Re-treat the plant in a week. “This is a marathon. You can’t just treat once and forget about it because new mealybugs are going to hatch, so you need to keep inspecting the plant,” says Del-Pozo. Check for several weeks, re-treating as necessary.
• Consider using a systemic insecticide. This is watered into the soil and requires the insects to feed on the plant, delivering a toxic dose of the insecticide. Choose one that’s labeled for mealybugs and for houseplants.
• Know when to call it quits. If you’ve tried to get the infestation under control for a few weeks and things aren’t improving, you may need to dispose of the plant. “Sometimes you have to sacrifice for the good of your other houseplants,” says Del-Pozo.

Signs of Mealybugs

Mealybugs are tiny (1 to 4 mm long) and soft-bodied beneath their waxy coating. Male mealybugs have wings, females do not. The females will lay 200 or more eggs, protected by cottony eggs sacs, which then hatch in a few days into crawlers that creep away to find new places to feed, says Del-Pozo. Indoors, multiple generations overlap, if left unchecked.

Small numbers of mealybugs may be missed on houseplants because they wedge themselves into plant crevices and at the base of stems. Once the population ramps up, you’ll see the pests themselves, or you may notice that the plant’s leaves are yellowing and sections of the plant are beginning to die. If the plant is failing, it’s likely already too late to stop the infestation, says Del-Pozo.

How To Prevent Mealybug Infestations

Because these insects are notoriously difficult to control if you’re dealing with an indoor infestation, these tips can help protect your plants:

• Inspect houseplants regularly. “Don’t just water your plant every week. Look at it and pay attention to anything new or unusual so you can catch pests early,” says Del-Pozo.
• Don’t put your houseplants outside for the summer. If your plants are healthy, placing them outdoors puts them at risk for picking up all kinds of pests, including mealybugs, aphids, and spider mites.
• Treat outdoor plants before bringing them in for the winter. If you must bring outdoor plants inside for the winter, spray them down with a hose first, then treat proactively with an insecticidal soap. Inspect again after a few days before bringing them indoors.