Scale and frost bite?

[Amym]

After being advised on these very helpful boards that another cactus of mine had scale, I began to worry.

When I bought this one I was told it got frost bite (the darker spots) so I assumed that’s what everything on it was. Now I’m afraid that it’s also scale.

Thoughts? I did try scrapping a few pieces and it did come off but there are some pretty hard ones. I don’t want to lose it!!

[stefan m.]

Scale and what i assume is corking. Some of it could be sunburn.
Scabs could be also from overwatering,
Frostbite is way nastier and worse looking than what you have here.
Also PLEASE REMEMBER TO ROTATE THE PICTURES.

[Amym]

Should I scrape all except where the arm is?

The last time I posted the pictures the correct way you had told me to rotate sideways which is why I did it this time, was unsure why you were asking that...

[stefan m.]

Scabs you should not scrape, and neither sunburn. Scale comes off easiliy , are small, so that should determine what is scale and what is not.
What i meant was---
1-Cacti are easier to id when the plant is in portrait
2- Pictures taken on a phone , rotated 90" take less space.
So, to help you easily, make sure the plant you want to show is upright.(as it would be in real life). Most of your photos you take depict the plant vertically, but you post them as landscape, and thats what makes the plant./pest harder to id)

[WayneByerly]

PLEASE REMEMBER TO ROTATE THE PICTURES.

Stephan ...
Not saying that this IS what happened, but in Amym's defense, I've had this system rotate a number of pictures that were NOT landscape mode pictures INTO landscape mode. Its happened to me on 3 or 4 occasions.

[WayneByerly]

I am far from being the most qualified expert on this forum, but I will give you my opinion and you can take it for what it is worth.

Scale
First, I don't believe that what I am seeing on the cactus in the picture that you posted is Scale. The spots on your cactus are brown and look like some damage/condition IN the cactus skin. Scale is an insect hiding under a 'shield' ON the surface of the cactus. This 'shield' is white-ish with a tan spot right in the center. Here's a picture of Scale that I copied from https://cactiguide.com/cactipests/#scale.

scale_pachycereus_a_800.jpg (74.56 KiB) Viewed 694 times

If you were here in the United States, I could recommend a number of pest control chemicals, but from the spelling of your name, I suspect that you are not. So I don't know what I can tell you about that. If you can tolerate a friendly query, in what country DO you live in? If you don't want people to know, then just ignore the question. I won't mind ... just curious ...

As a slightly interesting ancillary note, the following is an excerpt from the text on that same page about scale:

• "According to Wikipedia there are over 8000 species of scale insects."

So if it is NOT Scale, then what is it? Again, not being expert, I cannot say with any certainty, but it looks somewhat like some pictures of corking that I have seen, although 'corking' is something that I have normally seen at ground level. Not saying that It can't appear elsewhere however.

Corking
Go to Google, and execute a search for "cacti with corking" and then switch to the "images" view (button in the upper left of the screen) to see a great number of pictures of cacti with corking. Here's a single picture of corking that looks somewhat like what I am seeing on YOUR cactus:

Corking 1.jpg (112.12 KiB) Viewed 694 times

Frost Damage
I am also of the opinion that your cactus does NOT suffer from frost damage. I've seen damage from frost on globular cacti that is in places other that just the tips, but MOST of the pictures that I've seen of Frost Damaged Cacti show the damage on the tips. Here (also from cactiguide.com ... https://cactiguide.com/cactipests/#frost) is a picture of frost damage:

frost_pilosocereus_a_200.jpg (10.04 KiB) Viewed 694 times

An additional note regarding frost damage. You'll note that in the following picture, the action being taken to prevent frost damage is to cover just the tips.

Frost Protection.jpg (86.44 KiB) Viewed 694 times

Finally, I would like to ask you to NOT depend on anything that I have opined here. I am NOT an expert, but I DO know how much I've appreciated ANY help that I have gotten from this forum. The one thing that I would hope that you could take from this reply is that it is comparatively easy to do research yourself on the Internet. I in NO way wish to discourage you from asking questions here, but the lesson about learning to do research on my own has been extremely valuable to me. Use this forum as a start, and then go teach yourself.

I hope some part of this helps you in some small way...

[hegar]

Hello Amym,
I agree with WayneByerly letting you know, that there most likely is neither a scale insect infestation nor a mealybug problem. The lesions shown are way too big to be qualifying for an armored scale. They could have been caused by a mechanical injury or perhaps feeding by an insect. They also may be of a pathogenic nature. If this is a fungal infection, you would be able to see some fuzzy growth (mycelium, conidiophores and spores) or you may see small cushion-like structures or tiny grey to black spots within the spots on the plant. Those would be fruit structures that fungi produce.
There is also a very slight possibility of a rust pathogen, which would manifest itself in the form of rupturing blisters that contain brownish or dark grey contents (spores).
Well, as WayneByerly already stated, it is very difficult to arrive at a valid identification. So, whatever anyone tells you, it may or may not be correct.
On my job I usually insist on the specimen being sent to my laboratory, because I do need to see everything highly magnified and - if the pathogen is a fungus - to encounter the spores, in order to arrive at a valid diagnosis
I do consider the lesions on your plant to be not of a very serious nature. I suggest, that you keep an eye out for any changes in appearance of the lesions. If they do increase in size or in number, you most likely do have a pathogen on or in your plant. If there are no noticeable changes, the problem is just cosmetic in nature.
If you want to take a look at some cactus problems, go to the Home Page here and click on the tab "Pests and Disease".
As stated above, your cactus does look rather healthy and I would not worry about anything at this time, if nothing changes.

Harald

[Amym]

Waynebyerly - I actually live in the US! My name is Amy.
I really appreciate all of the advice you gave and did some research like you suggested and It does look more like corking
And thank you too Harald!
I’m going to keep an eye out to see if anything gets larger but for now I will say it gives my cactus character:)

Now I’ll be focusing on trying to take care of the one I scraped bc it looks to be in bad shape

[WayneByerly]

Ahhhh... Then that would actually be "Amy M."

When I saw "amym", i thought it an unusual name and probably foreign to the United States in origin, and so looked it up to see what it might mean. Hence my question (the name "amym" does exist BTW) . I am amused that I was so mistakenly confused.

Welcome to the cactiguide forum and the world of 'growing cacti' by the way, where according to Professor C. D. Darlington ‘cactus taxonomy is the pursuit of the impossible by the incompetent.'

There are a great number of truly friendly and knowledgeable people at this forum. I have never been cursed by anyone here and have always garnered several gems of very useful knowledge whenever I post a question here. I think you will very much enjoy your stay here.

[WayneByerly]

I actually live in the US!

Ahhhh ... then I may offer you a piece of information about a readily available material for insect control. Should that problem ever arise. It's called "Safer BRAND End ALL INSECT KILLER". It's a USDA approved organic insect killer and is supposed to kill 45 different insects, from the eggs through larva to adults. It's also supposed to be safe enough to use on crop type plants right up until the day before harvest. The three active ingredients are 1) potassium salts of fatty acids (which disrupts cellular membranes which causes the insects to dry up from the inside out and die), 2) extract of neem oil (this blocks the insects ability to feed, so it starves and dies) and 3) pyrethrin (which shuts the nervous system down, resulting in death of the insect) .

It is available at amazon.com

The last time I bought it, I paid $12.45 for a 32 oz spray bottle. The cost right at this moment is $13.24, so there's no saying what you'll pay for it, except it's not very expensive.

Its ASIN is B00314DYNW. Go to amazon.com and search for that ASIN. That'll take you right straight to that page.

I hope you never have occasion to need it, but in the event that you do, you now know where to acquire it from, and that it's a safe, inexpensive and effective insecticide.