Have a 6 or 7 foot cactus that was given to me in Oct. 2004. It is in a pot in our house in Minnesota. Last year it started growing fairly rapidly from the top, putting on about 8 to 10 inches of growth. In the same location, this winter it turned black on the new growth and the new growth wilted. In the middle of the stalks they have started turning a gray green color that appears to be spreading. I water about once per month. The plant has been in the same location for about 3 years. It sits in a corner exposed to morning sun and away from windows. The grey appears to be spreading rapidly but the blackend tips don't seem to be getting any worse. What is wrong and what should I do? Also, what kind of cactus is it? There are 3 separate stalks with 5 ribs on each stalk. The ribs have clusters of spines in the edge with the clusters being about 1/2 inch apart. Any help is greatly appreciated. The plant has great sentimental value for my wife and I.
looks like it's some kind of fungus. i'd cut off the parts that are completely gone - cut low enough so you get to healthy material as you want to make sure to get all the rotted part out. you can treat with a systemic fungicide - i've heard bayer's works well. i've not had need to use it though. can't help with an id.
I have found the name. It is called Twisted Cereus, Spiraled Cereus Cereus hildmannianus f. tortuosus. I sprayed with anti fungal and hope that will help. If anyone has any other ideas please respond. It has not been exposed to freezing temps or hot sun. It is inside all of the time and sits in a protected corner. No one goes near it but me and I only go near to water. It was doing fine until the last few months.
any kind of extended breeze could be the problem - you may not even be aware that there's a draft - they'll feel it though. if you have replacement windows anywhere nearby, please check to see that the top sash is ALL the way up and make sure to lock the windows...those top sash tend to work their way down over time if the lock isn't in place - especially if the windows are on the older side as they warp over time due to sun damage.
Thanks for the thoughts. We have crank out windows that only open from the bottom. Those are never opened and seal quite well. There is a floor vent nearby but it is turned away from the plant. The ceiling fan hasn't been turned on in over a year. The pictures show that one bad gray area and some smaller areas of graying. What is more difficult to see are areas about four or five inches up from the soil that are turning lighter. Currently they are a lighter yellowish green but that is something I have not seen before.
did these spots start appearing after a repotting? if so, then the soil may have been contaminated and i'd suggest dumping the soil completely and washing the container with bleach and rinse well - first with hot water and then a couple more times with cold water. use fresh soil. could also just be something that is in the ductwork and it landed on the plant and ended up with proper conditions to grow...changing filters yearly most people do - it's actually having the ductwork itself cleaned that people don't think of. if you haven't ever had that done, might want to do so :) i've had problems with my windows not staying up unless the lock is engaged (and the plants in the room got too cold), so, just thought i'd mention it... you CAN put the ceiling fan on - the plants will benefit from air movement. in fact, problems like fungal attacks can be kept at bay with air movement.
It's the original pot and potting soil. The plant is so large it is difficult to repot. I will try the ceiling fan to prevent further contamination. I had a person tell me it might be root damage caused by overwatering or underwatering. They suggested I try something called Superthrive to correct any root damage. They also suggested cutting off the bad parts and repotting the good parts after letting the parts "heal" for a few days. Any suggestions on how to handle a plant this large with out injuring it or becoming injured?
i'm sorry!!! i missed your last reply!! if it's been in that soil for more than 3 years, the least that needs to be done is to replenish the soil - it might even need a larger container (if the root ball is large enough - probably is, too, if it's been that long). i wouldn't do any treatments with fertilizer until you are sure what is going on...root rot would only occur with overwatering...other problems with root would be a root mealy infestation and the only way to get rid of them is to repot with fresh soil (and sanitize the container if you're going to continue using it)...i'd also recommend a systemic treatement be done, as well, to get rid of root mealies. yes, that's a mighty cactus and will take a fair amount of preparation AND help to do anything with it!! any time i'm handling a spiky i use a combination of things to keep from getting stuck. depending on size of the plant and it's spikies i may use tongs and/or just leather 'rose' gloves. i've also used layers of newspaper or a piece of cardboard (folded around) to hold the plant to move it. for something that large, i'd wrap it in a few layers of newspaper or cardboard and then cover that with a towel and lightly tie it in place so that you have a good area to grasp it to move it. it should be fairly easy to just tilt it over and support the body of the cactus on, say, pillows, so that you can unpot it and take a look at the roots. in fact, you can possibly do that part alone. getting it up and into a container again will definitely require two people, though. unless you wanted to create new plants. once it's laying on it's side you can just cut it (about mid-way) and then set those pieces aside to callous over before potting up (you would also cut off those top portions that are bad). the bottom portions should then be managable for one person to unpot/repot them - they'll continue to grow after you top them off.
Thank you so much for your response. I have been traveling and not in a place to check my email. The gray areas spread and dried completely out. I have cut two of the stalks off completely and have set the green areas aside to cure with the plan of repotting. The remaining stalk had to be cut off to about half of it's height to try to remove the bad and hopefully salvage the remaining part with the root. In looking at the bad parts, the areas turning lighter green had brown areas in the core of the plant. I cut back far enough to leave what looked healthy green. I plan to repot all three pieces in new pots with fresh soil once they have cured. If there are any helpful hints you can give me regarding the repotting, they will be appreciated. Thanks again, Ray The gray areas I wrote about originally dried out and were brittle obviously cutting off nutrients to the rest of the plant.
could you use boric acid on it? I've read lots of wonderful things about its fungicidal and general pesticide characteristics of boric acid. Not sure how it would be in contact with the plant tissue, but I'm sure you could do a patch test. Edit: I just read your most recent post. I hope your surgery has worked. I had some neglected Stapelia I found that I had to nurse back to health, and one of them did something very similar to this, I just cut off the affected parts. Good luck to us both!
