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Mealybugs on Orchids — Do This

Mealybugs are fascinating to read about or watch how they interact with plants in gardening documentaries. 

On your plants, the results are not fascinating at all. Mealybugs are fast orchid destroyers. 

The males are said to be shorter-lived, but that does not matter. What does matter is they are ALL killed. 

Did you know that the long-tailed mealybug does not lay eggs in the soil? 

The female of the Pseudococcus longispinus species give birth to live young! The live young from the female bugs can be as many as 600 bugs in under 10 days. That is their lifespan. 

It does not take a math genius to work out that those numbers on any orchid plant are fatal! 

Read on to discover the necessary steps required to eliminate mealybugs before they destroy an orchid. 

Getting rid of mealybugs on orchids requires treating the leaves, stems, roots, and the potting mix. The eggs or live young result in root mealybugs. Getting rid of the infestation requires the leaves to be treated with neem oil or insecticidal soap, repotting, soil sterilization, and root pruning. 


Treating the leaves

The leaves are the area to tackle to eliminate the live mealybugs. There is little point in treating any eggs or orchid bugs in soil when there are actively feeding and breeding on the foliage. 

Two solutions exist to treat the leaves on orchids. 

  • Insecticidal soap 
  • Neem oil 

Either of these is how to get rid of mealybugs on any plant. Orchids are no different. 

What is different is the time of day you apply them. These are soapy solutions that coat the leaves. Applying them when the temperatures are high (above 85-Fahrenheit) can cause leaf burn on orchids. 

Apply these by either rubbing or spraying the solutions over the leaves in the morning, or move the plant into the shade to prevent hot sunlight from heating the oil. 

Every area of the leaves and stems need to be coated. 

Mealybugs are sneaky critters that will hide between the folds of leaves and tight crevices that make them hard to detect. Even one survivor will retrigger the reproduction process. 

The process will need to be repeated multiple times because these work as contact insecticides only. 

When spraying, the soap or oil needs to come into direct contact with the soft-bodied skin of these insects. Upon contact, mealybugs dehydrate within hours. 

If they are missed when spraying, the leaves will dry and the insecticide will no longer be effective. 

Repeat applications daily. Each morning, knock the leaves to knock off as many mealybugs (live and dead) as possible, then respray the leaves. 

Treat and replace the soil mix

Getting rid of the mealybugs on orchids is not a guarantee that the plant is entirely free from them. 

The mealybugs feed on the leaves on the plant, preferring to stay above the soil. 

However, they do drop eggs onto the soil. If those are not removed or treated with a pesticide, the next problem that will need to be addressed is root mealybugs. 

Root mealybugs are tiny white bugs in soil that deplete the roots and plants of nutrients. Adult mealybugs do not bore into the soil. They lay their eggs or live young on the soil surface. 

Once those are hatched, the bugs bore into the soil and begin to feed on the roots and soil nutrients. 

As the bugs mature into adult mealybugs, they venture beyond the soil surface, get onto the leaves and the whole process starts again. 

To truly eradicate mealybugs from orchids, the potting media should be replaced, or at the very least sterilized. 

The potting mix can be sterilized the same way you would sterilize the soil for houseplants

Using steam, bake the mix in the oven, in the microwave, over a grill, or solarization by leaving the mix in direct sunlight to cook. 

The aim is to increase the soil temperature to at least 180-Fahrenheit and keep it around that temperature for at least a half-hour.


Washing orchid roots

Treating the orchid roots is different. Exposing the roots of the plant to extreme temperatures can do just as much damage as the root mealybugs do. 

To wash the roots at high temperatures, boil some water then let it cool. Dip the roots in purified water while it is still warm and let the roots soak for around ten minutes. 

The warm temperatures and short time will be sufficient to either drown any hitchhiking mealybugs attached to the roots or knock any lingering eggs loose into the water. 

After soaking the roots, gently shake them and leave them to air dry for a little while. 

As it is drying, prepare the new container by wiping it down with rubbing alcohol (70% isopropyl).


Pruning damaged roots 

Before repotting the orchid in the freshly sterilized potting mix, insect the roots for damage and prune off any rotted roots.

If you’re unsure about how to cut orchid roots, it is straightforward. Start by disinfecting your pruners or scissors, inspect the roots for soft brown patches. Those are rotted. To cut them off, make the cuts diagonally.

Once finished pruning the roots, spray them with hydrogen peroxide (3%) solution. 


Repotting your orchid

Before repotting your orchid, mix in some Diatomaceous earth (DE) through the potting mix. 

The sharpness will take care of any lingering eggs that did manage to survive your attempts at sterilization. 

Mealybugs are stubborn and difficult to get rid of so every trick in the handbook needs to be implemented to make sure they do not return. 


Frequently Asked Questions related to getting rid of mealybugs on orchids


How did my orchid get mealybugs? 

Mealybugs are everywhere. The only way to prevent mealybugs is regularly coating the leaves with a neem oil application. It is a fungicide and an insecticide. If the leaves are not protected, mealybugs, thrips, aphids, and other sap-sucking pests will find the plant and set up home. 


Do ants eat mealybugs? 

Ants and mealybugs have a symbiotic relationship. Ants do not eat plants or mealybugs. They feed on honeydew – the excrements of sap-sucking insects. Ants protect sap-sucking insects from natural predators. Getting rid of mealybugs will cause the ants to move onto another food source. 

Author Bio

Daniel Iseli

Taking care of houseplants and gardening are my greatest passions. I am transforming my apartment into an urban jungle and am growing veggies in my indoor and outdoor garden year-round.