Am I looking at Scale?

[CoolestGravy]

I'm growing concerned that my Fairy Castle Cactus has Scale. Most of these spots have been present since 8/2023, probably for longer.

Is this Scale, something else, paranoia? If I do have an infestation, I'll also be eager to hear remedies. My current thought is to rub it down with rubbing alcohol and give it some Bonide Systemic in spring.

I hope you're having a nice day!

[Steve Johnson]

Looking at photo #1 -- if those little white things come off easily with your fingernail or tweezers, you have scale. And you'll need to physically remove the scale insects since alcohol won't do anything. Good news is that you're dealing with a very low-level infestation. Re. Bonide, see the PM I just sent you.

[CoolestGravy]

Any time I've tried to remove any spots, I've really had to pry it off. To the point that it seems to have left minor damage.

[Nino_G]

Looks like a calloused tissue that develops after epidermis is pinpricked (possibly by the spines of other cactus if they were transported together).

[Steve Johnson]

Any time I've tried to remove any spots, I've really had to pry it off. To the point that it seems to have left minor damage.

Then you don't have scale. Here's what CactiGuide's founder Daiv Freeman has to say about it:

• "I am not sure if some species of cacti have skin that is too tough for the scale or if they just don't taste good. I suspect the former, however, as scale will often be found only on tender new growth and not elsewhere on a cactus."

Could be a combination of both -- if you're not seeing any scale insects on your Fairy Castle's new growth, the plant probably doesn't taste good to them. I think Nino's assessment is correct.

[CoolestGravy]

Thanks so much everyone! This guy is my first cactus, so it's a little special to me.

I'll keep an eye on things and read more into the systemic measures Steve told me about. Maybe take the same pictures in a month so I can see if anything changes. I'll probably also make a thing of carefully scraping more concerning looking spots to see if their anchored or not.

I welcome any further input, but either way, I hope you all have a fantastic week!

[CoolestGravy]

Yesterday I scraped off a couple spots that's sending my mind back to scale being a real possibility. In spring I plan to take systemic measures.

But while waiting, I was thinking about using some Diatomaceous Earth. I know it wouldn't cure anything, but maybe it could slow things down, if scale? What do you guys think?

[Steve Johnson]

Yesterday I scraped off a couple spots that's sending my mind back to scale being a real possibility. In spring I plan to take systemic measures.

But while waiting, I was thinking about using some Diatomaceous Earth. I know it wouldn't cure anything, but maybe it could slow things down, if scale? What do you guys think?

Never had a use for DE, although some members claim that it'll kill root mealies. It won't do anything to slow the spread of insect pests going after the stem. The only thing you can do before spring is to scrape off the scale. Now that I think about it, your fingernail might damage the Fairy Castle's skin, so use a blunt object like a q-tip handle or plastic ballpoint pen cap. I know this may be a bit "labor intensive", but a low-level scale infestation is relatively easy to deal with while the temps in your house are still in the 60-70 degree range.

[keith]

Usually you can see the tiny white insect under its shell if its scale . You scrape them off but they come back . scale infestations on my cactus always came back after scraping it off . they come off pretty easy and grow back fast I think they live in the soil before climbing on the plant and making scale shells.

imidacloprid works