Help! Mealybugs on my Cactus – Let’s Get Rid Of Them

A featured image showing an up close picture of my cactus with mealies clearly visible on the right hand side with the text "Ugh! i have mealies too - let's get rid of them together! on the left hand side

We’ve recently had a new arrival in our family, a beautiful baby boy!

As you can imagine, my poor plants had fallen to the bottom of my to-do list for the last few months and the result?…..

Mealybugs had attacked two of my smaller cacti!

My Lobivia arachnacanth clustering cactus on the left and my Mammillaria spinossima cv. Un pico on the right hand side that have become infested with mealybugs.
My plants have been attacked! You’ll see some close-ups in the following sections

I’m not too worried though. As cacti collectors, these little critters are just something we have to deal with from time to time.

I’m about to share with you exactly what I did to get rid of them so you can follow along.

They say prevention is better than cure so I’ll also share with you what I’ve learned about preventing (or limiting) this happening in the future.

How to Identify mealybugs – A closer look

Mealybugs are small whitey-grey bugs that remind me of small woodlice.

A small cluster of mealies at the top of my Mammillaria spinossima
A small cluster of mealies on my Mammillaria spinossima

They have a strong, protective waxy coating which makes them difficult to get rid of.

The first signs of mealies look like small masses of cotton wool on your cactus.

The mealies are harder to see on my Lobivia arachnacanth but you can see what looks like cotton wool spread over the plant

Although they may look cute up close, these little critters suck the sap from your plants or attack the roots, slowly weakening them over time.

Do this as soon as you spot them!

If you only read one section in this article, let it be this;

As soon as you the first sign of mealybugs, quarantine it from the rest of your plants immediately.

In a different room ideally, as they spread fast. Luckily, mine had only jumped to one other plant when I spotted them…phew!

How to treat mealybugs

# Step 1 – remove it from the pot

First, we need to remove our cactus from its pot, using gloves of course.

A mealbug infested Mammillaria spinossima  removed from it's pot with the roots exposed laying on a sheet of brown paper.
You can see the mealybugs on my Mammillaria spinossima before we zoom in!

Carefully brush away as much soil as possible to expose the roots.

# Step 2 – Use a spray

There are plenty of ready-mixed sprays available but these are packed full of chemicals which I’d rather not use on my plants (unless I have to).

Instead, I prefer to make my own.

I’ve seen people recommend either just Isopropyl alcohol or just dish soap. Both report great results so I use a mix of both.

I mix one part tap water;

With one part 70% Isopropyl rubbing alcohol…

A 500ml bottle of 70% strenght Isopropyl rubbing alcohol

And a single squirt of dish soap.

A bottle of fairy liquid
I’d prefer to use natural soap but this is all I had to hand

I believe the dish soap breaks down the waxy body and then the alcohol will kill them.

I mix it up in a spray bottle which you can pick up for a couple of dollars if you don’t already have one lying around the house.

Important! Always test the spray on your plant on a small, inconspicuous area before to check for any adverse reactions before your spray the entire cactus.

A thin, black reusuable spray bottle that I purchased from amazon stood next to my cacti
A cheap spray bottle that I bought from Amazon for a couple of dollars

Then simply spray your infested plants including the roots. I strongly recommend you do this outside if you’re using alcohol or at least in a well-ventilated room.

My gloved left hand in the picture with my black spray bottle spraying myMammillaria spinossima

Be sure to get in every nook and cranny!

What if you don’t want to use alcohol?

Maybe you don’t have any or you’d rather not use it on your cacti.

I get it. In this case, you can always just use the dish soap and warm water.

I’ve used it successfully a couple of times in the past. I’ve only added the alcohol now as an extra step to be sure I get them all!

What if you don’t have a spray bottle?

I also see people recommend dipping Q-tips in the solution and applying it directly to the bugs.

This is great for the larger bugs but I don’t see how you’ll be able to get the small ones and all of the hidden eggs with this method.

Alternatively, you could always submerge the plant in the solution using a bowl for a few seconds and then rinse off as described above.

Step 3 – Don’t forget to clean the pot!

You’ll likely find mealybugs in the pot, underneath the pot, and maybe even on the hard surface where the pot was standing so we need to clean these things too.

One of the empty pots with a little soil left containing what looks like evidence of mealybugs that needs to be cleaned out.

Remove as much soil as you can with a brush and soak with the same solution.

The two empty plant pots from my infested cacti soaked with the solution

Step 4 – Let’s hose them down!

Set the plant and pot aside and let them sit for 30 minutes. It’s important to keep them out of direct sunlight to avoid sunburn.

Have a quick look and you should see the mealybugs have turned to a green, mushy substance.

Ooops! I forgot to take a picture to show you what they look like after being sprayed!

We need to thoroughly rinse the plant and pot off. I like to use my garden hose but you can use a tap if you wish.

Getting ready to rinse of my cactus with a hosepipe outside in my garden.
Carefully rinse the solution from the cactus

Step 4 – Let them dry

First, I like to carefully detangle the roots using a comb.

Carefully combing out the tangled roots of a cactus

Then we need to leave them somewhere to dry for 2 or 3 days but again, avoid direct sunlight as this can easily scorch our plants.

Step 5 – Inspect and then replant

Now they’re dry, take a few minutes with a magnifying glass or the zoom mode on your phone, and make sure they’re aren’t any signs of bugs or eggs.

If not, we’re good to replant.

As it’s autumn here now, I’m going to leave these unpotted until spring as they’re in a dormancy period.

If you’re in the growing season, let them dry out completely before replanting.

Even though we’ve removed the mealybugs and replanted them, I’m still going to keep them away from my other plants for 3-4 weeks to be sure that I didn’t miss any and I suggest you do the same!

I don’t want to risk affecting the rest of my collection.

Why didn’t I simply remove the mealies?

I’ve seen a lot of advice online saying you can simply pick them off.

I tried this the first time around, but they hide in every nook and cranny, underneath and in the roots and that’s just the big ones!

If you catch it early enough, you may be able to do this successfully but in my experience, simply picking them off a heavily infested plant is virtually impossible.

How to prevent mealybugs in the future

Inspect any new plants in the nursery for signs of pests before you buy them, and quarantine at home for a few weeks before introducing them to your collection.

I set aside some time once a week (usually on a Sunday) and inspect each plant. By doing this I can usually catch pests in the early stages before they start taking over!

Going forward, I’ll be regularly using neem oil to help prevent mealybugs as both a spray and adding it directly onto the soil.

This will also help keep away those less harmful but pesky gnatflies.

I’ll be doing a full article walking you through the process of using neem oil very soon!

Over to you

Did you follow along with me? If so, how did you get on? I’d love to hear all about it in the comments section below, I look forward to talking to you.

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