White Stuff on Plants: Does Your Houseplant Have Mealybugs?
If you look closely at your houseplant and notice little white tufts of something that looks like heavy cotton lint, it's probably mealybugs. Mealybugs give the appearance of lint due to a waxy outer residue that they secrete for camouflage and protection. Underneath that coat, the mealybug looks a lot like an ancient trilobite, only much smaller.
Mealybugs usually originate in the foliage crowns of infected plants or at leaf stem joints. Most commonly, you'll find the white residue in these areas first, but if your problem has advanced, these pests will spread out to more joints, foliage crowns, or further out along the foliage and down stems.
Mealybugs will also produce a sticky substance called honeydew that will coagulate on the leaves, giving the appearance that something has been splashed or spilled on the plant.
If you have positively identified mealybugs on your plant, do not worry; it is not a death sentence for your plant. However, it will need to be treated and quarantined.
How to Treat a Houseplant Infested With Mealybugs
Here is how you can get rid of mealybugs.
Step #1: Isolate the Infested Plant
Mealybugs have a piercing mouthpart on the underside of their bodies that they use to bite into houseplant foliage. They lay eggs along the foliage that they inhabit and easily contaminate anything that touches them.
Due to the ease of contamination, mealybugs are also easily spread to other plants that may be touched after the infested plant has been touched. Because of this, one of the first steps in taking care of an infestation is to make sure the plant is quarantined as best as possible. If you come into contact with the infested plant, it's important to wash your hands before touching any of your other houseplants.
Step #2: Remove the Mealybugs
As part of the removal process, mealybugs must be wiped away completely. They are best cleaned off with baby wipes or a wet paper towel. A sponge also works well but should not be reused on any other plant after being used on the infested plant.
After the mealybugs have been wiped away, spray the infected area down with a light solution of water and insecticidal soap, dish soap, or a very effective and natural soap called Dr. Bronner's. Not much soap is needed in this solution; a mere teaspoon in 20 oz of water is plenty.
Spray this solution on the plant leaves and wipe them clean again; this will serve to further clean off more eggs that may have been left behind. The soap will also coat the leaves (if any mealybugs ingest the soap, it will kill them). This cleaning process will need to be repeated regularly.
Step #3: Cut off Any of the Infected Parts
If an area of a particular plant has a spot that appears to be the epicenter of the infestation—dracenas (sometimes called corn plants) will commonly get mealybugs that are nestled down in the new growth crowns—cut off any of the infested crowns. Don't worry; the plant will easily regenerate, and the foliage was damaged anyway due to the pests.
What If You Still Have Mealybugs?
If you have followed and repeated the steps above and the mealy problem is still persistent, there are insecticides (referred to as systemic insecticides) that can be used to treat the problem. Since these insecticides can be hazardous to the plant itself along with other living creatures if used excessively or improperly, only use them as a last resort and follow the instructions carefully.
Systemic insecticides are absorbed into a plant's entire system through the roots. They come in liquid, granulated, and powder forms and are added to the soil. As the insecticide is absorbed by the plant's system, the plant itself becomes toxic to the mealybugs, killing them off by essentially poisoning their food supply.
How Can You Prevent Mealybugs?
Since mealybugs seem to come with the infested plant (unless the infestation is accidentally transferred from one plant to another), it's a little difficult to prevent them entirely. However, the following measures can be taken to help ensure that a problem doesn't worsen.
- Keep your plant clean by wiping the leaves down with baby wipes on a regular basis; remove any debris and/or potential pests that you notice.
- Keep your houseplant in stable condition by watering it properly and keeping it in proper environmental conditions. A plant that is struggling in any way is more prone to be attacked by pests of many kinds, including mealybugs.
If you know what kind of plant you're dealing with and maintain it with care, mealybugs should be of little to no worry.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: I have a natal mahogany tree that is healthy but is attracting ants which are leaving a sticky mess on the leaves, aside from pruning, what treatments can I use?
Answer: It is likely that the ants are actually there because they are feeding on the sticky substance on the leaves, they are not usually the cause of the stickiness. The culprit of the sticky substance on the leaves, called "honeydew", is most likely mealybug, scale, or aphids. The honeydew is excrement from these common pests, and ants love to feed on it. Identifying the pest responsible for the honeydew, and neutralizing it will resolve the problem.