It looks like it could be mealy bugs. Try googling them so you can look at the pics. The bugs themselves look like little tiny walking cotton balls sort of. Am I making since? If you google it and you think I'm right, you need to quarantine the infected plants and start treating right away. Hope this helps

Mealy bugs. Hard to get rid of them all. They could also be in the soil. You could soak boiling water on the soil while you soak the plants in warm soapy water,,, or resort to insecticides...

Yes, they are mealy bugs. The first step is definitely to quarantine any affected plants. Make sure you really check all your plants, not just the ones where they are readily visible, because they can be expert hiders.

Leaf or surface mealy bugs are different from root mealy bugs, but it is possible to have both. I would try pulling up a plant or two to check; if you don't see anything, you probably only have the surface bugs.

Treatment can be a bit of a pain, but you can find lots of information on what solution to use on the forum. I have used a 50/50 water/alcohol mix with a squirt of dish soap, and I'm currently experimenting with Safer's Insecticidal Soap. So far it seems to be working well.

Definitely make sure you spray and/or remove what you see, but I always like to spray the whole plant in case there are things I can't see going on. Because soaps and pesticides often work on certain, but not all, parts of the life cycle, you will have to do several treatments. The life cycle is around 3 weeks. I like to spray once every few days (spraying every day seems too hard on the plant, in my experience). Then, be sure to keep your plants quarantined for a few more weeks to be sure all the bugs are gone before you put them back with the rest of your collection.

Good luck!

Oh no, thank you.

Are mealybugs able to stay in the environment (without plants) for long?

I had something similar on a small plant about 4 months ago in the same room and got rid of that plant in a hurry, and these in the photo only arrived 2 weeks ago, they belong to my friend who hasn't had issues so it leads me to think they would have come from here somehow.

My own plants are in the balcony and I'm having aphid issues there so have been careful to tend to her plants before going out to mine.

They can hide under the lips of pots and next to the pot stands as they create more nests...

Oh no. This is heaps of mealybugs rather than cactus fuzz isn't it...?? argh.

{{gwi:629961}}

Oh dear! I'm afraid so. That one is so badly infested, honestly, I would get rid of it. It would be extremely difficult if not impossible to treat and it's really a risk to keep it if you have other plants. Even when plants are separated it is possible to spread mealy bugs if any bugs or eggs accidentally end up in your hair, on your clothing or your skin.

argh.
Thanks!

My plants are outside and I have ants - tons of ants. They delight in spreading mealies and aphids. I have had them on Dracaena, Echeveria, Kalanchoe and Adenium. I've even had a couple on my jades. However - I do not have any cacti, so take this advice with a grain of salt.

For the occasional mealy that I find, I remove it with a q-tip dipped in alcohol. Then I spray with 50/50 alcohol. I repeat the spray in 5-7 days.

For a heavy infestation, like pictured below, I wiped off what I could easily see and then treated with Bayer 3-in-1. Left the plant in bright shade and then treated again a week later.

Maybe this will work for you, or maybe you want to cut your losses now.

I've only had mealy bugs once, and used the alcohol and water formula recommended by spapa. Didn't need to treat the plant a second time.

You can also use systemic insecticides which are effective against mealy bugs.

The systemic I've read about using for mealy bugs is a Bayer product containing Imidacloprid. That's a rather nasty chemical, but then you're not spraying it into the environment, and you're not eating the cacti/succulents. [Whatever the formulation's name is, it's a U.S. product.]

Thanks, all.
I've removed the very infected cactus and happily couldn't see any in the roots, although I can't be sure there weren't just a few hiding that I missed.

On closer inspection most of the other pots had a wisp or two here and there too, unfortunately they were all close together as this was a temporary arrangement. I've wiped off what I can find, and will see what happenes in the next few days before considering systemics.

Does random spraying of alcohol on the environment around the plant (window sill, floor) help? Or at least not harm the plant, as I've done that ... :P