Heres a couple of photos of my Astro and Opuntia sp(Sorry about the picture size). On the Astro, its a little orange dot, but it is depressed in, i looked around the plant and saw on the tip of the ribs, there is a couple, but because its skinny on the tip, i can see light through it.
On the Opuntia, it has affected every pad... i guess where they are isnt good, theyre covered by tin roof, but to the side is open shade cloth. But they shouldnt be recieveing much to little water.

The opuntia looks like the stuff we are talking about and it's not good. Have a good read of this thread and make up your own mind on treatment. The good thing for you is the growing season is about to start and this will help get rid of it.

The astro looks ok. The marks on the skin are typical of astros especially the marks on the ribs. Do they get any direct sun ?

I will read the thread carefully and make a decission. If worse comes to worse, i can just burn it and buy another one from the market.

Not sure about the Astro, so im going to watch it a bit more and see. Where the Opuntia is, it gets a bit of sun, being right next to the shade cloth, but not enough to burn it. The Astro is on the ground but still recieves light. Alot of my other plants are sunburnt from neglect awhile ago when i just wacked them into their new spots, bit down on that, some are really bleached.

Also HN, would it be possible for you to maybe upload some of your Astro collection, prefferably your cv's?
I need to upload my SK-Cap pics.

The astro looks fine I have seen the marks on mine with no ill effects

I have my Opuntia like yours not protected and one new pad has been growing slowly all winter........ the pad in the first pic I would take off as it looks pretty bad

Hahaha i hope so

I didnt think it would grow during winter? From what i remember, dad potted it in just normal dirt, and i havent noticed it growing, so maybe your's is doing better then myne Yeh i think i will, but the others are getting that way aswell.

the hakuun actually looks alright. i'd keep an eye on the spots though.
in fact it looks better than mine because it's getting all corky at the base and also has a split down the base of the side where the hylo pushed it way do hard... that and i kinda overwatered last summer lol.

Yeh mynes very corky at the base, and the stock is old and warn out, so im thinking of degrafting it and putting it on its own roots.

i am thinking of doing the same. be sure to do it when it warms up and pump the scion up as much as possible before degrafting so it has good water reserves to work with while its thinking about rooting.

You took my idea 8| Haha ive been talking bout this since last growing season, as you should know.
Seeing ive taken this topic majorly offcourse, how long do you think it should take to establish roots?

A combo of nasty chemicals might be the best way to treat orange rot. Or like kada says, bright and dry...

damage to Pelecyphora from this automn

Damn, that looks nasty. Are you treating it with anything?

No. I might be stupid to not treat such a valuable plant, but I suppose the harm is done [marks]. I generally avoid using chemicals... If it gets worse I will have to... I sprayed with nicotine solution earlier for what I thought was mites, but I think this is orange rot again...

Any suggestions is welcome.. I am monitoring it closely and If I see worsening, I will spray with a combo of antifungals. But the temperature is falling and I hope keeping it dry will stop it...

Oh. I remember I did make a spraying with that year old combo I kept in a spraying can.... Maybe I should repeat or make fresh.....

I've been looking at more natural remedies myself lately and just came across a couple here



Rust can also be controlled with sulphur, and
homemade sprays made from Chamomile, or a blend of Chive, Horseradish, Elder and Casuarina
leaves.
http://www.thewaterwisegarden.com/rust.htm

The Chamomile looks easy anyway

and here's another one with a few different remedies

http://www.figtree.org.au/natural_pest_control.html