Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
While pruning some shrubbery one summer day, I found white fuzzy stuff on the stems and leaves. When it moved, I realized it was insects. I was shocked to learn that they were mealybugs. I thought mealybugs only survived indoors on houseplants. I wasn't aware that they can be a problem outdoors as well.
What are Mealybugs?
Mealybugs are small armored insects that suck sap from plants, eventually killing them. Plant sap is similar to our blood. If plants lose too much sap, they will die just as we die if we lose too much blood. The insects' bodies have a waxy coating that makes them impervious to insecticides. The females are 1/8 to 1/16 inch long and wingless. The males are smaller and have wings. They have wings so that they can fly around in search of females. The males don’t feed. They have very short lives, only living long enough to fertilize the females and then die. The females lay 50 to 200 eggs in a sac two to six times a year, depending on the species. Most species do not survive the winter. They need warmer temperatures which is why they are such a pest year round indoors on houseplants or in greenhouses.
Mealybugs don’t move far on their own. Most infections are the result of new plants which are infested with them being brought into your garden or your home.
Ants can also move mealybugs from plant to plant. The mealybugs secrete honeydew, which ants eat. They are known to “farm” mealybugs, protecting them from other insects and harvesting the honeydew.
Always Isolate New Plants
Always check new plants carefully for mealybug infestation before purchasing them and bringing them into your home or installing them in your yard. Even if you don't see any, it is a good practice is to quarantine new plants for a few weeks before planting them in your garden or introducing them into your home. Any infestation of mealybugs will show up during that time.
Wash Mealybugs Off of Your Plants
An easy way to rid your plants of mealybugs is to spray infected plants with a hose that has a high pressure nozzle attached. This will knock the insects off of your plants. This won’t kill the insects nor will it get rid of them completely. It merely minimizes the infestation, making it more likely that your plants will survive.
Shortly after I discovered the infestation on the shrubs that I was pruning, we had a hard rain. When I checked the shrubs the following day, all of the insects had been washed away by the force of the rain.
Indoors, you can simply place infected houseplants in your sink and use the sprayer to remove the insects. Don't forget to wash under the leaves where these insects can hide. Since the plants are smaller and you can be more thorough, this is a good way to completely rid your plants of this pest.
Pick Mealybugs Off of Your Plants by Hand
For smaller infestations, you can remove mealybugs from your plants manually. Use a cotton swab dipped in rubbing alcohol to remove the insects from the plants. Alcohol dissolves their waxy covering, so this method also kills the insects.
Use Sprays Made with Soaps or Oils
Spraying infected plants with insecticidal soaps, horticultural oils or neem oil are safe, organic ways to kill mealybugs. All three are readily available at your local nursery or online. The oils and soaps smother the insects, killing them. Make sure when you spray that you get the undersides of the leaves and the stems of the plants where these insects often hide.
Use Beneficial Insects
Outdoors, encourage beneficial insects to visit your yard by not using insecticides or herbicides which can kill or harm them. Ladybugs, parasitic wasps, lacewings and syrphid flies think mealybugs are delicious. Ladybugs can be purchased online and released into your yard. Just be aware that once they have eaten all of the mealybugs, they will fly away in search of food rather than waiting around to see if more will appear.
Most plants can tolerate mild infestations of mealybugs but when they become too numerous, they can literally suck the life out of your valuable plants or houseplants. Protect your home and yard from these insects using these simple, organic steps.
Questions & Answers
Question: Is there a way to keep mealybugs from the garden? It is not possible to pick them off tomato plants. Do they come out of the soil, or do they fly and lay eggs?
Answer: Mealybugs were introduced into your garden either through new plants that were infested, or ants brought them in. Ants "farm" mealybugs for their honeydew which the ants eat. The mealybugs and their eggs live and die on your plants. They do not fly or live in the soil. If you cannot pick them off, you can hose them off or spray your plants with insecticidal soaps, horticultural oils or neem oil which will kill them.
© 2017 Caren White
Caren White (author) on June 06, 2019:
Mealybugs infest the plant parts that are above ground, not the roots. If you have an infestation, remove the infected plants and dispose of them in the garbage. That should take care of the problem before they spread to other plants.
Ten on May 30, 2019:
how will you know which mealybug it is? I scared it will spread in the roots..
Caren White (author) on January 10, 2018:
Jim, as a Master Gardener, I always recommend organic solutions to gardening problems. Thanks for reading and commenting.
Jim Ferringer on January 10, 2018:
I tried soap and oil and still had Mealybugs. I finally used Systemic Granules byBONIDE, I now have zero Mealybugs
Caren White (author) on September 05, 2017:
I love that idea! Organic solutions are always the best. Thanks for reading and commenting.
Danesh Kumar on September 04, 2017:
In Wayanad Dist, Kerala, we face this problem on coffee plants, found a cheap solution , spray diluted rice gruel water, water discarded after cooking rice, dilute it four time with water, and spray it, as it dries, the mealy bugs limbs become stiff, become immobile , and fall off..
Caren White (author) on August 01, 2017:
They are a nuisance, aren't they? Thanks for reading and commenting.
Mary Wickison from Brazil on August 01, 2017:
I think these are the little critters which get on my tomato plants. I pick them off by hand but they seem to cause the plant's leaves to curl.
I too am all for natural predators in the garden.
Caren White (author) on July 26, 2017:
RoadMonkey, I wrote a hub on ridding your garden of thrips. I didn't know that they are a problem indoors, though. Have you tried insecticidal soap or neem oil? They smother insects. Spray the entire plant, expecially the undersides of the leaves where they hide. Let me know if it works for you! Thanks for reading and commenting.
RoadMonkey on July 26, 2017:
Very useful, thanks. I haven't had mealybugs on my plants but one of my old indoor plants keeps getting thrips that I try washing off.