Food-Gardening Lessons From A Wartime Victory Garden

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Tag: Mealybugs

How Do I Remove and Manage Mealybugs?

“What is the best way to remove ground mealybug or should I dispose of the whole plant?” Question from Erin of Conover, North Carolina

Answer: Mealybugs can be overcome. It just takes a little time and patience. The main reason is that one has to eradicate both the adults as well as the juvenile crawlers, which are almost invisible to the eye. Outdoors, ladybugs and other natural predators keep populations down, but inside the house mealybugs can take over a plant really quickly.

How To Manage Mealybugs

Here is an excerpt from my blog, Managing the Worst House Plant Pests:

Mealybugs are soft, white, and feed on the juices of plant leaves and stems, particularly in the crevices between leaves and stems. Mealybug infestations are hard to manage because these pests travel and spread as crawlers. Crawlers are the nearly invisible nymphs that hatch from the pest’s white, cottony egg masses and “crawl” several feet to quickly infest other plants. You can’t always see these crawlers, so to manage them, you have to clean plants, containers, and surrounding surfaces when you see an infestation.  They produce copious crawlers, so the sooner you notice mealybugs, the better.

At high populations, mealybugs produce lots of cottony egg masses, adult bugs, and nearly microscopic crawlers. All must be completely removed if the plant is to be saved. (Image by Alexlutor)

To remove mealybugs, start by cleaning your plant, its pot, and all surfaces surrounding the plant. Remove the top two inches of potting soil and replace it with fresh. Finally, spray the plants. One of the best mealybug sprays is a 10-25% solution of isopropyl alcohol. Fill a spray bottle with 1/4 cup of isopropyl alcohol and 2/4 cup water and shake to combine. When treating plants with this solution, keep them out of direct sunlight because it can cause leaf burn in the bright sun. You can also treat plants with insecticidal soap or Neem oil. Repeat spray treatments until plants are mealybug-free.

Another method to stop crawlers is to surround infected areas with double-sided tape traps. As the crawlers hatch and begin crawling, they will get stuck on the tape and die. You can also surround plant bases and pot edges with double-sided tape to keep crawlers from moving beyond an infected plant.

I hope that these tips help!

Happy gardening,

Jessie Keith

Black Gold Horticulturist

My Gardenias Have Root Mealybugs. Help!

“I have tried growing gardenias, but they always die. When I pull them up there are white bugs all over the roots. What are these and how do I get rid of them?” Question from Sheila of Tampa, Florida.

Answer: There are several pests and diseases that will attack gardenia roots. I am glad that we narrowed yours down to root or ground mealybugs (Rhizoecus spp.) in our email communications. Here is a little more about these pests.

About Root Mealybugs

Root mealybugs also feed on the roots of African violets, grasses, palms, citrus, pineapple, mangoes, and other plants. The sucking insects suck the life out of the roots. This eventually will kill a plant. These pests will live for 27 to 57 days on a host plant, but cannot live off of a host for long. The females lay eggs and live young, called crawlers, hatch in just one day. Crawlers are microscopic but can travel several feet in search of a plant to feed on.

Root mealybugs are certainly a serious pest to manage, but there are some safe management practices that will enable you to get rid of them. Here are some cultural and organic treatment methods for their removal.

Cultural Controls

1. Remove all infected and surrounding plants and dispose of them far from the garden.

2. Do not replant gardenias where you had them previously planted without allowing the soil to remain unplanted for at least several weeks.

3. Check the roots of all new potted gardenia or other plants that you bring into the garden. Ants like to feed on the sugary dew created by mealybugs, so you will often see ants in infected pots or around infected plants.

Organic Treatment Methods

These pests are REALLY difficult to control, as you have already discovered. Here are some methods that are approved for organic gardening and have been shown to work. All products need to be applied as drenches.

1. Insecticidal soap drench: Apply insecticidal soap as a drench, being sure to apply enough to reach all of the infected plant’s roots. Be sure to follow the manufacturer’s recommendations.

2. Standard soap root drench for potted or uprooted specimens: Mix one teaspoon of Ivory liquid into 1 quart of water and drench the roots. This can kill the mealybugs at all stages. Repeat every couple of weeks until the problem appears to be gone.

2. Pyrethrin drench: Apply standard pyrethrin as a soil drench rather than a spray. Be sure to follow the manufacturer’s recommendations.

Some advocate digging up plants, treating their roots with a bowl/tub of drench, and replanting them elsewhere.

I hope that these tips help you tackle destructive root mealybugs.

Happy gardening!

Jessie Keith

Black Gold Horticulturist