Cactus mold

[kinless]

I've got a little exotic collection of cactus species, and I threw in some columnar cactus to balance it out. They're now twice as high as when I planted them.

Problem is, in the past few months I've got what looks like beige-colored mold growing on them. I can wash/rub it off but it always seems to come back. Not sure if there's a way to prevent this from happening in the first place. Any kind of spray or remedy I can use to minimize or eliminate the issue?

(There is a water fountain on the ground next to the plant stand, but it's much lower than where these are, and is low-flow/no splash, so I can't imagine water/moisture would be causing it, but I'm sure someone would know better than me.)

Thanks!

~j

IMG_0280.JPG (36.18 KiB) Viewed 578 times

[george76904]

Is it like fluffy whispy stuff? Because it looks like mealies. Do a search on the forum for how to get rid of them.

[iann]

Looks more like scale than mealies. Scrape some off and take a close look. Mealies have what looks like wooly coverings, but is really quite waxy. Uncovered they have a distinctive oval segmented appearance, often with small thin protrusions around the sides, and sometimes with two tails. Scales hardly look like insects at all, more like little limpets. You could treat either pest with a systemic soil drench which would hopefully kill them all in one go, but try to idenitfy them first. They are both quite resistant to spraying.

[kinless]

Thank you for your input. After closer examination, it looks like they are indeed scales.

I still need to re-organize and re-pot several plants in this bowl, so it's best I probably remove the infected cactus and treat it. Just strange that the bugs only attacked the right column and left the other two alone. (They did spread to that smaller cactus below the infected column so looks like I'll be treating that one too.)

Any suggestions on soil drench? Or will any consumer-grade soil drench work?

~j

[greenknight]

You should treat any plants that were in contact with it.

[george76904]

Looks more like scale than mealies. Scrape some off and take a close look. Mealies have what looks like wooly coverings, but is really quite waxy. Uncovered they have a distinctive oval segmented appearance, often with small thin protrusions around the sides, and sometimes with two tails. Scales hardly look like insects at all, more like little limpets. You could treat either pest with a systemic soil drench which would hopefully kill them all in one go, but try to idenitfy them first. They are both quite resistant to spraying.

Yes they do look more like scale. I was trying to view it on my phone, but I just got it pulled up on a computer and that is clearly what they are. Sorry for the misinformation I recommend neem oil (very carefully applied), and if it makes you feel better to see them you can wrap the plant in double sided tape and see them stuck to it after a week or so... I have never used the tape method though (only on trees) but it seems like it would work if you could get it around the spines.