Opuntia pad problem?

Trouble shoot problems you are having with your cactus.
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fanaticactus
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Joined: Sun Oct 25, 2009 7:44 pm
Location: Grand Isle Co., Vermont

Opuntia pad problem?

Post by fanaticactus »

I raised this from a seed. It's about 5 or 6 years old. It had several more pads but they broke off. Now there's this gray area around all the areoles on just one pad. It's not soft or powdery...just discolored, and I don't see any bugs. The other picture is of the pad next to it, and it's perfectly fine. What's going on?
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Catch a falling star--but don't try it with a cactus!
dvdmsy
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Re: Opuntia pad problem?

Post by dvdmsy »

This happened to one of my opuntias. I believed that its growth was stunted on account of this (I decided that it was a fungus), and I discarded it, I'm sorry to report...
fanaticactus
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Joined: Sun Oct 25, 2009 7:44 pm
Location: Grand Isle Co., Vermont

Re: Opuntia pad problem?

Post by fanaticactus »

dvdmsy wrote:This happened to one of my opuntias. I believed that its growth was stunted on account of this (I decided that it was a fungus), and I discarded it, I'm sorry to report...
Oh well...it's had a rough life but it's the only cactus I have that was raised from seed. I have notoriously bad luck getting anything past about 1/4" tall. Do you think I should rescue one of the good pads and try to root it? Or might the fungus (or whatever) have spread to areas that aren't visible yet?
Catch a falling star--but don't try it with a cactus!
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hegar
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Re: Opuntia pad problem?

Post by hegar »

I have seen a number of pathogens on cacti, but this one stumps me. There seems to be a water-soaked margin around the lesions, which would indicate some kind of leading edge of an infection. Most of the spots are located around the areoles of the stem segment, but there seem to be some "sister-colonies" of the pathogen developing.
I would go ahead and cut a healthy looking pad off the plant, place it for a week or so on its side, so the cut can heal, and then transplant this stem piece into clean soil and place it some distance from the cactus with the spots.
If the pad develops the same kind of lesions, then it would seem to me, that the pathogen is a systemic one, i.e. it is present throughout the plant.
You could also go ahead and apply a fungicide. There are a number of systemic kinds on the market, including one called "Halt Systemic", Fertilome systemic, Benlate DF, Bonide "Infuse", and Spectracide Immunox.
These are not inexpensive and you may be better off to discard the plant, if it turns out, that all parts are diseased, including the new growth.

Harald
fanaticactus
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Joined: Sun Oct 25, 2009 7:44 pm
Location: Grand Isle Co., Vermont

Re: Opuntia pad problem?

Post by fanaticactus »

hegar wrote:I have seen a number of pathogens on cacti, but this one stumps me. There seems to be a water-soaked margin around the lesions, which would indicate some kind of leading edge of an infection. Most of the spots are located around the areoles of the stem segment, but there seem to be some "sister-colonies" of the pathogen developing.
I would go ahead and cut a healthy looking pad off the plant, place it for a week or so on its side, so the cut can heal, and then transplant this stem piece into clean soil and place it some distance from the cactus with the spots.
If the pad develops the same kind of lesions, then it would seem to me, that the pathogen is a systemic one, i.e. it is present throughout the plant.
You could also go ahead and apply a fungicide. There are a number of systemic kinds on the market, including one called "Halt Systemic", Fertilome systemic, Benlate DF, Bonide "Infuse", and Spectracide Immunox.
These are not inexpensive and you may be better off to discard the plant, if it turns out, that all parts are diseased, including the new growth.

Harald
Thanks, Harald. Seems like a wise analysis. I did cut off a pad; actually, it broke off when the parent fell over in the wind. That separate pad seems to have escaped any signs of a similar fate. The other pad on the parent plant is still OK, so the whole situation is very strange. I did spray once with a surface fungicide. I think I want to cut the separate pad more or less in half so there is more surface area from which the roots can grow. Maybe I'll also plant the 'pointy' end, too, just out of curiosity and see which one does better. I hate to ditch the entire cactus because it's the only one I have that I raised from seed that came from a supermarket 'tuna'.
Catch a falling star--but don't try it with a cactus!
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