Black spots!

[Absinthe]

I recently discovered these black spots on my bridgesii. I can't work out whether it is some kind of damage from getting too cold overnight, or a fungus, in which case I would have to perform some major (painful) surgery. Any idea's as to what it is, and suggestions on what I should do?

http://shaman-australis.com.au/gallery1/al...i/ach.sized.jpg

Thanks, Jon

[hairyplant]

without doubt a fungal problem....

[planthelper]

this one, slow to heal...

but not deadly.

saw it at some pedros i recieved,

the blue healed up, forming dry mosaic patterns.

no idea what's causing it either, but i guess it's too much moisture (glasshouse problem?!).

i got all my pedros outdoors,

and there, i never encountered this problem.

[mr toodly]

Do you suggest removal of the tissue in question?

[Guest electro]

if it feels mushy cut it out (cut heaps extra out to ensure that you get it all) - asap

ive had spots liek that eat 60cm high cactii in a matter of days...

if it isnt mushy though it isnt the same thing so it might be ok to leave them there ...,

[Absinthe]

The spots are not mushy, and don't appear to be increasing in size, however I will be checking every day for any signs of activity. I also posted at Gardenweb and received this reply:

Jon,

Most probably this is a fungus. Actually the most dangerous for cacti and very difficult to get rid of. It only attacks the softest and most active parts of the plants like growing points, areols and flowers and invades and destroyes the vascular bundles within short time. Its scientific name is Helminthosporium cactivorum or Drechslera/Bipolaris cactivora. It mainly attacks South American columnar cacti and Echinocereus.

Try rescueing your plant by cutting off and disposing the pups immediately. And separate it from the other plants for a while and check your other plants very thoroughly!

This made me a little unhappy to say the least. It think I will take a risk, and leave it unless there is activity, in that case I will be removing all the pups I hope it doesn't progress any more. It might even pay to (sacrificially) cut open one of the pups (not the black bit) to see if the inside is fine or not.

Thanks for the help guys.

Jon

[Flip]

without a picture... I'll take a shot at my opinion.

It's a common fungus that that has a affinity for the

cacti, small, back fuzzy spots?

it'll attack open wounds and can (in my experience)be easily managed

if your plants are healthy and in a proper enviroment they'll

be able to hold off anything serious.

IMO do not cut into or scrape your plant in and effort to

remove this one. I believe that it resides upon the skin of the cacti

in the same manner natural yeasts reside upon grapes waiting

for the chance to invade. resulting in natural fermentation.

keep the grapes dry and it won't sour garps to bit into.

I've had it show up on a few of my fresh cuttings as well as

water damage on the top of the tips of the plants.

Generally the plants can deal with it on their own.

nothing to worry about, unless it manages to invade into

the deeper soft tissue (either with a bacterial associate or not)

the tissue will liquidfy and turn brown with a type of boil showing.

This would be a much more serious problem and

may require a bit of surgery to stop additional damage.

but I've not had it happen unless the plant is housed in a bucket of water.

The best medicine is to have it exposed to

DRY FLOWING AIR and perhaps a bit of good old sunlight.

But then again, I live in a warm and generally semi arid enviroment

from what I understand, many on this board reside in the much

more humid places -still they should be able to handle it.

Bests!

[ 22. August 2004, 06:56: Message edited by: Flip ]

[Rev]

Flip:

The best medicine is to have it exposed to

DRY FLOWING AIR and perhaps a bit of good old sunlight.

But then again, I live in a warm and generally semi arid enviroment

from what I understand, many on this board reside in the much

more humid places -still they should be able to handle it.

Bests!

that be the truth! Ive seen identical clones - some near the coast and some inland - the caostal ones melt over a week to a foul smelling goop while the inland (low humidity) ones scar up and keep on growing

Humidity is the killer. If it gets away dont hesitate to be brutal in the extreme in removing a hefty portion of teh cactus well away from the infectionsite (itll be running down the vascular tissue)

Sulphure doesn nothing to stop it, or copper, or any fungicide yet tried

salvage what you can and well ..mm.. dispose of the rest thoughfully

[Absinthe]

Update on situation...

I noticed the spots beginning to spread, and also turning mushy. I decided it was time for some surgery. I didn't get your post Reville until today, after the operation was complete. Anyway, I unpotted the whole thing (ouch) and decided to play it by ear, and cut into one of the pups. It wasn't too deep, so I cut all infected tissue out, being careful to be sterile at the right times, and it didn't turn out too bad. I basically covered the whole base/exposed tissue with "Rose Dust" which contains Mancozeb and Sulphur. I read up on the fungus, and found Mancozeb was suggested, and I also know cacti don't have any problems with it. So now, I have left it, unpotted, and will check to see if anything develops over the next couple of weeks. If not, I'll repot and drench with another fungicide. If so, then I'll just have to cut a whole lot more off.

Cheers,

Jon

[Rev]

Great!

Its only since this thread that ive known the actual pathogens name

For example look up 'Black Rot' for succulents, cacti and orchids and youll get a host onf names

Mancozeb eh?

Is that a systemic? Maybe i could protect my stock plants with an injection once a season

Ive lost some pretty special single specimens to that fungi - and plants taht grow very well except where i live ATM

Please let us know how it goes

[Absinthe]

Rose Dust: 300g/kg sulphur, 40g/kg mancozeb, 5g/kg rotenone. I think the mancozeb is a contact fungicide, not sure about the rotenone. It is used as a dust, not in water.

Anyways, I used compressed air to blow off all the dust, and discovered the black rot had begun again at a point where I expected it might. I decided to be safe and cut the whole bottom portion off, and will reroot the cactus. I kept the bottom bit with the pups, just to see what will happen to it.

Reville: Did you end up getting your Pereskiopsis?

Cheers, Jon.

[Rev]

Well i may have just in the last few days

i haveto check the box

still waiting on it o/wise

i sent the guy my 1/2 of the trade about a week and a half ago

sometimes thse sthings can take a bit longer

I hope iget it soo as theyll be taking off with this weather

[infinite_monkey]

dont know if it helps at all but i have a Pereskia aculeata var godseffiana getting to about the size for taking a cutting or two if your perskiopsis doesnt make it, asuming of course your using it for grafting, though you can eat it just no fun hiding in side

[Rev]

Im always up for a new grafting stock

I can swap another grafting stock if u like

T pachanoi, Stapelia gigantea, Ceropegia woodii, Hylocereus undatus, T spachianus.

anyway update on black rot

I have had zero outbreaks since starting a prophylactic treatment of mancozeb during muggy periods on all single specimens and susceptible clones

[planthelper]

sorry for sidetracking...

more than a week ago, i grafted a small hoodia gordoni onto a ceropegia woodii. i did this out of emergency because the bottom section of that hoodia was seemingly dead and very shriveled.

the hoodia is very prone to curving up the edges,

so trim the edge off using a 45 deg angle.

a pice of wire was heated with the lighter and holes got poked stratigigily ( word sorced, australien crawl, boy's light up) positioned on the top of the pot, holding the bottom section.

small hook's got bend and inserted at the holes.

those hooks are used to fasten our rubberband to!

make sure beforehand that there is just perfect downward pressure produced. adjusting this this can be achieved by lenghening or shortening of the hooks.

the graft still looks good,

but i am worried about one thing,

the potatoe like woodii tuber did not show any sigs of cambium layer, so i could not watch out for alingement. question, how much would you cut off the woodii tuber?

just a 2-3 mm slice to the surface, thats what i did, or is cutting deeper better?

i will go now and halve a woodi tuber to find out if there are prefered layers hidding inside...

no there are not!

in other words, it's important do match the white ring if doing peyote on pedro or pereskiopsis.

but the woodi tuber is just like a potatoe,

does that mean i don't have to worry about alingement and just keep both cut's the same size?

[Rev]

Nice work Planthelper

maybe you should start new thread on this

this deserves it

I thought the benefit of Ceropegia woodii was that you dont need to match up the bundles cos there arent any

im growing lots of these for future stocks and now stapelia gigantea too.