There are more than 2,000 species of mealybugs in the family Pseudococcidae. Thankfully, you’ll likely only find two species of mealybugs on houseplants! Their name refers to the white secretions covering their bodies. That look like finely ground meal[5]. They feed on a wide variety of ornamental plants indoors and outdoors.
While mealybugs are not harmful to humans. If left unmanaged, they can ruin your houseplants. They cause damage by feeding on plants and excreting honeydew. Honeydew is a sticky, sugary substance that can allow black sooty mold to grow on plants[2]. They will also leave their white, waxy secretions on plants.
What Are Mealybugs?
Mealybugs are white fuzzy looking bugs in the order Hemiptera. They use their piercing/sucking mouthparts to feed on the nutrient-rich sap. In large numbers, their feeding damage and the nutrients they steal can harm plants.
Females have pinkish bodies that appear to be segmented[3]. They are covered in a white, waxy, almost powdery looking secretion. The waxy increases as they get older. Eventually forming long filaments on some species which are used for species identification.
Adult males are tiny and rarely seen. They have wings and two long wax filaments protruding from the end of the abdomen[1]. They only live for 2 to 3 days for mating and don’t eat[1,2]. Male mealybugs are able to fly to find females for mating. Though many species don’t require mating to reproduce[1].
Types of mealybugs
There are more than 275 species of mealybug in North America[5]. The most common mealybugs you’ll find on houseplants are the citrus mealybug and longtailed mealybug[5].
Citrus mealybug (Planococcus citri) can be identified by the faint gray strip that runs down their back[1]. Short filaments protruding around the edge of their bodies with two slightly longer filaments at their rear.
Longtailed mealybugs (Pseudococcus longispinus) also have filaments around the edge of their body. But they are longer than the citrus mealybug. They also have two very long filaments protruding from the rear that can be longer than their entire body[2]. These filaments can often break off. Causing them to appear shorter in some individuals.
These tiny white bugs tend to cluster together and hide at the base of plants. In the crotches of stems, or under leaves making them difficult to detect early on. Look for signs of mealybugs such as honeydew, black sooty mold, or the waxy secretions they leave behind.
How to get rid of mealybugs
First and foremost, move any infested plants to a different room. Since mealybug females can’t fly, and crawl very slowly, this will prevent their spread. Remove as many bugs as you can by gently rubbing them off the plant[3].
To get rid of mealybugs naturally, use rubbing alcohol to instantly kill them. You can apply 70% rubbing alcohol directly on mealybugs using a cotton ball or swab[3]. This is the best mealybug treatment. Make sure to test a small spot on your plant for adverse effects 1-2 days before treating the entire plant[3].
For severe infestations, use a mixture of 1 part 70% rubbing alcohol to 3 parts water and spray the entire plant. Repeat this spray once per week for several weeks for complete control[3].
Insecticidal soap and oils can also be used to control mealybugs. They coat the body, essentially suffocating the insects. Direct contact is necessary for soaps and oils to be effective. And multiple treatments are necessary for complete control of mealybugs.
Other insecticides are ineffective against adults due to the protection their waxy coat provides. They may work on newly hatched mealybugs. But still should only be used as a last resort for heavy infestations or high value plants.
How To Prevent Mealybugs
Plants kept indoors year round are only able to get mealybugs if you bring them inside. They can be brought in on dirty gardening tools, infested soils, or on new plants you don’t realize are infested.
Make sure to clean all gardening tools before using them on indoor plants. Only use sterilized soil when repotting plants. If you purchase new plants, it is best to quarantine them for one month. To ensure they don’t have mealybugs before putting them near other plants.
If you put your indoor plants outside during summer, there are many other ways they can be infested. Outside, mealy bugs can be dispersed by birds, pets, and immatures can be carried by wind. Check plants carefully for signs of mealybugs before bringing them back inside. Even better, quarantine them for one month before placing them near plants you didn’t put outside.
Frequently Asked Questions
Yes, mealybugs can spread to other plants but only if they are relatively close since they can’t fly. Plants in separate rooms of your home are far enough apart to prevent spread. If you’re worried about spreading, you can place sticky traps around an infested plant. Which will stop mealybugs in their tracks.
Thankfully, if you find mealybugs on your indoor plants, you don’t have to worry about them infesting your house. They move very slowly and won’t move very far from their food source, your plants. Removing or treating infested plants is the only thing you need to do to get them out of your home.
There are many species of soil mealybugs in the genus Rhizoecus[4]. They feed on the roots of plants which makes them very difficult to detect and even harder to get rid of. Always make sure to use sanitized potting soil. To reduce the risk of introducing soil mealybugs to your plants.
References:
[1] Buss, L. (2012, September). Citrus mealybug – Planococcus citri. Featured Creatures. Retrieved September 30, 2022, from https://entnemdept.ufl.edu/creatures/CITRUS/Planococcus_citri.htm
[2] Byron, M. A., & Gillett-Kaufman, J. L. (2016, August). Longtailed mealybug – pseudococcus longispinus. Featured Creatures. Retrieved September 30, 2022, from https://entnemdept.ufl.edu/creatures/fruit/MEALYBUGS/longtailed_mealybug.htm
[3] Flint, M. L. (2016, March). Mealybugs. How to Manage Pests Pests of Homes, Structures, People, and Pets. Retrieved September 30, 2022, from http://ipm.ucanr.edu/PMG/PESTNOTES/pn74174.html
[4] Frank, S., & Baker, J. (2010, August 1). Mealybugs Entomology Insect Notes. NC State Extension. Retrieved September 30, 2022, from https://content.ces.ncsu.edu/mealybugs
[5] Shour, M. (2004, February 27). Mealybugs: A common houseplant pest. Horticulture and Home Pest News. Retrieved September 30, 2022, from https://hortnews.extension.iastate.edu/2004/2-27-2004/mealybugs.html#:~:text=Although%20there%20are%20more%20than,the%20United%20States%20since%201879