How to get rid of mealybugs on indoor plants

It starts out looking innocent. Like white fluffy patches on your plants. But look closely and you may find the culprit. Mealybugs. The good news is there are multiple, effective treatments that will get rid of mealybugs on your indoor plants. Here are the best two that work for me...

 

Mealybugs are a pest both indoor and outdoor gardeners have had to contend with for over 100 years. It feels like there's a remedy for each of those 100 years. If you look up treatment options you may be overwhelmed (I know I was). But the good news is there are a couple in particular that work best to rid your indoor jungle of mealybugs. 

However mealybugs are also one of the most difficult pests to completely get rid of because of the combination of their lifecycle as well as where they like to hide out. But it absolutely can be done with a little patience, especially if caught early.

What do mealybugs look like?

There are a few types of mealybugs but the one you'll most often see attacking our indoor plants is the longtailed mealybug like these guys below, called Pseudococcus longispinus.

 

They are small, white, and appear fluffy, but are actually covered in a powdery wax that repels water-based insecticides (which is why you need a different approach to other insects, and why what you've tried so far might not have worked).

They also like to hide out in difficult to treat areas. They are pretty easy to spot as adults can reach 3mm to 5mm long. If you don't see any adults you might first notice white 'fluff' in the crevices or leaves on your plants, like this below.

 

 

What conditions do mealybugs like?

Mild temperatures and high humidity are the conditions mealybugs love. Spring is a favourite. Although you can get them any time of year indoors. Eggs hatch every 2-3 weeks, which is why repeating treatment at least every 2 weeks is required. Extended periods of hot weather will reduce their numbers. 

 

Are root mealy the same?

You might also have heard of root mealybugs or 'root mealy' which target roots. Because they live below-ground, treatment of root mealybug is different from the more common mealybug found on foliage and flowers. If you're on a mission to get rid of mealybug above-ground, this guide is for you.

How to treat mealybug on indoor plants

 STEP 1: Move the plant

No matter how bad the infestation, the first thing to do is move that plant ASAP. Or if it's not an easy one to move, move other plants nearby instead. One infested plant can quickly turn into your whole jungle becoming a victim to mealybugs. No thank you!

Once your plant's in isolation, get yourself some isopropyl alcohol, also called rubbing alcohol, but it's important to know the difference between the two.

Should I buy isopropyl alcohol or rubbing alcohol?

They are the same thing, however the concentration is different. Isopropyl alcohol (also called IPA) is 100% vs rubbing alcohol which is diluted, usually to around 65% to 70% isopropyl alcohol. It's the diluted one - called 'rubbing alcohol' - that you want to look for. But as a back-up, you can also dilute the 100% concentration as another option.

 

Where can you buy rubbing alcohol from?

The one I use is Isocol Rubbing Alcohol (that's if you're in New Zealand). For my international plant friends, the Amazon Basics 70% Rubbing Alcohol will do the job nicely. If I'm sold-out - or you want to get yours in-store instead of online - most chemists and hardware stores are likely to either have 100% isopropyl alcohol or rubbing alcohol.

 

STEP 2: Spray'n'Wipe

 
You can (and should) use the alcohol method two ways as it's most effective when both methods are combined. 

 

The first step is to kill the adult mealybugs. Dip a q-tip, cotton bud, cotton ball or cotton pad in rubbing alcohol (not 100% isopropyl alcohol). 

Press that on to every adult you can find, wiping them off the leaves as you go. It works instantly and those evil fluff-balls will turn orangey-brown when dead. You can wipe off the fluffy white nests too.

The second step is to mix 1 part of rubbing alcohol with 1 part water, and a couple of drops of liquid dish soap. 

Stir well and put that mixture in a fine-mist spray bottle, like the Mister 360 super fine spray bottles (those are available in NZ), which is the same as this Ultra Fine Spray Mister (that one's from Amazon).

(you want the finest mist possible as it's important to get really good coverage)

Spray everywhere! Leaves (top and bottom), stems and lightly spray the top of the soil too (don't pour it onto or through the roots however). Get that mixture into all those leafy nooks and crannies.

That waxy coating makes mealybugs almost water-proof, so the addition of that small amount of liquid dishwash soap (same as you use for washing up), helps the spray get through that waxy layer.  

It's important with this method that you wipe or spray down the plant thoroughly afterwards as it is a strong treatment.

Wait between 5 and 10 minutes maximum before completely washing it off. I do my treatment in the bath or shower so I can use the shower head to wash off the treatment - and every dead mealybug along with it!

TIP: If the rubbing alcohol or isopropyl alcohol you find has a bit less than 70% alcohol that's still fine to use for both steps above (the one I use is about 64% alcohol but that one from Amazon is 70%). You just don't want to go over 70% without further diluting the alcohol. Make sure you do a test patch first if your plant is sensitive or if you're unsure how your type of plants reacts to alcohol or to dish soap.

STEP 3: Fortnightly follow-up

 

Using a suitable pesticide that specifically says it treats mealybugs - like Enspray-99 or BioNeem - follow-up with a thorough spray of foliage (top and bottom), at least once a fortnight. Use a fine mist sprayer and spray just to the point of run-off.

If using both, or just using a neem product, check it's a registered pesticide. It should list mealybug on the label. That's important because most neem products are NOT tested or registered. Many have low levels of the active ingredient that is effective against mealybug.

They may work as a repellent to reduce the risks of pests setting up home, but if you only see claims like 'repels' or 'prevents' it's likely not a registered pesticide, not strong enough to work on mealybug, and may not work on when a plant is infested. Always check the label.

Only treating one plant? See if you can find the product you want but already mixed for you. Most pesticides are for indoor and outdoor plants, meaning they are often concentrates made to mix with water and you end up buying a lot more than you need.

Plus keep in mind, once mixed, you need to use it up or dispose of the mixture. You should never store pesticides once mixed. Always make and use fresh. This is why > Instead, either make up very small amounts from concentrate at a time, or buy them pre-mixed for you for smaller plant collections. For Enspray-99 for treating a handful of plants, I'd get yourself the Enspray-99 Ready-to-Use which comes with a super-fine mist spray bottle included. 

 

Should you repot when a plant has mealybugs?

 

Yes, if the infestation is really bad, or you just want to do everything possible to get rid of the mealybugs as thoroughly and quickly as possible, you can repot. If you've treated for mealybugs before and they keep coming back, I would repot.

 

You don't have to if you're concerned about how well your plant will recover, but it is recommended. Repotting can be quite stressful for plants so considering they are already been eaten alive by sap-sucking mealybugs, you may want to err on the side of caution.

 

If you do repot, remove as much of the old soil as you can, focused on the top 5cms or so of soil as that's where the eggs and larvae concentrate. Rinse the roots well. You don't have to remove every particle of soil. While you're doing that, it is really important to give the nursery pot and cover pot a good clean and sterilise too.

Give the pots a scrub and 'bath' either in a bleach solution (I use 1 part bleach to 10 parts water), or using hydrogen peroxide like Plant Care Plus to make sure any sneaky mealybugs are gone-burgers.

Hydrogen peroxide can be used both to kill what's in the soil and to clean the nursery pot and cover pot. I use Plant Care Plus in New Zealand, which is at the right strength for use with plants. If you're not local, have a look for Essential Oxygen Food Grade Hydrogen Peroxide 3% (available on Amazon).

After rinsing the roots, to kill what's left, water with a quarter cup hydrogen peroxide 3% to 4 cups water and pour over the roots before repotting. To clean the nursery pot and cover pot, scrub off surface soil, then mix 1 part hydrogen peroxide 3% to 1 part water in a tub or bucket. Fully submerge the pots in the cleaning solution. Leave them in the mixture until the solution stops bubbling. Remove them, rinse well, then leave to dry. You can re-use the same nursery pot and cover pot right away once dry, or repot into new pots.

 

Do you have to repeat treatment for mealybugs?

 

Yes, these guys are great hiders. You will need to repeat spray every 10 days to 2 weeks on average for at least one more time, but to be safe I'd recommend a fortnightly spray for 2 months total (so that should be 4 sprays total). 

If you spot any white fluff or individual mealybugs, use your rubbing alcohol again and wipe them off. Then spray and wipe down the leaves again with your rubbing alcohol, water and dish soap combo. Rinse afterwards. 

I've tried that, but mealybug keep coming back!

If you're treating a repeat infestation or really bad mealybug infestation, bring out the big guns and opt for a systemic as well. 

Contact insecticides like Enspray 99 and BioNeem are short acting, don't get absorbed into the plant, and need frequent repeat treatments. Ones like Enspray 99 are instant kill, others like BioNeem stop pests feeding and interrupt the lifecycle so they don't mature and breed.

But a systemic like Groventive (in NZ), or Captain Jacks Systemic Houseplant Insect Control (available through Amazon overseas), does get absorbed into the plant and travels around in the sap, turning your plant temporarily toxic to sap-sucking pests, including mealybugs.

You can spray Groventive mixed with Enspray 99 for the best results, or use Groventive by itself, and Groventive will keep working for around 28 days.

One spray may be enough if you are also using a contact insecticide like rubbing alcohol or Enspray, but you can spray Groventive again 28 days later if needed. Just don't go over 4 sprays in a 6 month period so pests don't get resistant. Enspray 99 and BioNeem don't have a maximum for houseplants and won't cause resistance but Groventive can. 

 

How long should you wait until a plant can come out of isolation?

Whatever treatment you go with, wait at least 2 weeks with no signs of mealybug before returning your plant to joint the rest of your jungle. All up, expect your plant to be in isolation for 4 to 8 weeks. 

 

Can you repel mealybugs to prevent getting them in the first place?

Yes, if you want to be pro-active, but don't see any signs of mealybugs in your plants right now, you can use neem oil as a natural repellent. I use the BioNeem neem oil diluted but you can buy diluted neem oil leaf shine products that act as a mild repellent, like Foliage Magic.

Before you treat

 

The same warnings apply when treating any type of bug, whether using a DIY method, home-made or store-bought: some plants are more sensitive than others and ALL plants can become more sensitive when under attack by pests.

If you know the plant you're treating has a reputation of being more sensitive, or you're not sure, only treat a small area on the plant first, wait at least 48 hours, and providing all is well, you can go ahead and treat the entire plant.

Common ones to watch for are ferns, succulents, orchids, begonia and peace lily as well as thinner-leafed indoor plants like stromanthe and some hoya.

Remember also to always keep the plant out of direct sunlight during treatment as sunlight + treatments can sometimes combine to scorch leaves until they've dried, usually a concern when using an oil-based treatment that can leave a residue behind and make plants temporarily more photo-sensitive (meaning they are temporarily more sensitive to light). 

As a general rule, always treat early morning. That's a good rule for outdoor plants also so beneficial insects are not out and about yet. Keep plants out of direct sunlight when leaves are wet.

Mealybugs suck 

Quite literally, that's how mealybugs feed on your plant. If your jungle keeps getting targeted by pests in general, I'd highly recommend adding silica to your entire jungle's feeding schedule.

In NZ the best two I've found are GT Silica or Dyna-Gro ProTekt. I'm not sure on sourcing GT overseas, but you can get Dyna-Gro ProTekt from Amazon internationally as that's an American brand.

Silica helps plants create a barrier against future attack from chewing and sucking insects, helping protect roots, stems and leaves, while helping plants recover and heal faster.

Silicon helps protect the rest of your jungle from attack also. It's nature's bodyguard for our indoor plants! Generally outdoors plant gets all the silica they need from soil water naturally, but indoor our plants miss out.


The sooner you start treatment for mealybug the better. I hope you're reading this 'just in case' but if you do have a mealybug infestation, now you're armed with the most effective method to kill mealybugs, as well as the ways to prevent them from coming back.

Remember eggs hatch about every 2 weeks so make sure you repeat this treatment at least once a fortnight later, and keep infested plants away from the rest of your jungle in the meantime. It can be done (with a little patience). 

 

Happy (pest-free!) growing,
Anna :)