Is this rust or frost damage?

Trouble shoot problems you are having with your cactus.
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Steve-0
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Is this rust or frost damage?

Post by Steve-0 »

Echino. texensis, in a ten gallon pot with O.polyacantha. Year round outdoors. Hard growing, purchased from Nevada grower a couple years ago.
Its pollinating partner is a few feet away in a similar pot and has no brown spots....yet. Winter is fading into spring. We have had some teen degree cold snaps and winter snow moisture.
The brown spots were noticed a couple of weeks ago. They are on the sunny side of the ribs only.
I bought some fungicide and treated it twice in the last two weeks.
Do I dig it up and isolate it?

Keep treating it with fungicide?

Do nothing?

Please advise.
Thanks, Steve
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Aiko
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Re: Is this rust or frost damage?

Post by Aiko »

Steve-0 wrote: Sat Feb 26, 2022 5:47 pm They are on the sunny side of the ribs only.
That sounds like sun burn as the prima candidate, I would say! It would be impossible for my plants in this time of the year, but I am sure your winters / early springs are much sunnier and you will experience much more sun intensity.

These should be quite hardy. 10F, that is -12C. I don't think that is too much for this plant, assuming it has not been like that for weeks at night.
keith
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Re: Is this rust or frost damage?

Post by keith »

Probably sun damage ? If it's rot the plant will be loose in the ground you can check that but watch the spines they are sharp on this species
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Steve-0
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Re: Is this rust or frost damage?

Post by Steve-0 »

It has been outside for two years in the same pot/location. Our high mountain desert climate is high UV solar radiation and can get 🔥 HOT 🔥 in July and August. The other horse crippler is 4 feet away in a pot exposed to the same conditions. With no brown spots or other ailments. All my outdoor in ground cacti seem to be thriving as well as the potted ones. July 2020 we had a significant heat wave which caused 135F soil temps in my potted cacti and all came through that just fine. I did move them all into shade during the peak of the heat.
The fungicide I'm using is basically a copper sulfate type which is supposed to cover rust and many other fungi infections.
We'll see what happens in the next few weeks.
Download
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Re: Is this rust or frost damage?

Post by Download »

Wrong place for frost or sunburn.

My money is on rust. It could also be that you watered on a sunny day and the water droplets focused the sunlight causing burns, but if that's the case my money is on the burns having opened the skin allowing rust to take hold.
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Steve-0
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Re: Is this rust or frost damage?

Post by Steve-0 »

Download wrote: Mon Feb 28, 2022 10:30 am Wrong place for frost or sunburn.

My money is on rust. It could also be that you watered on a sunny day and the water droplets focused the sunlight causing burns, but if that's the case my money is on the burns having opened the skin allowing rust to take hold.
Thanks for the response.

I did a little research/reading about rust on cactus and find it sure seems that is what my Echinocactus texensis has. The cause comes from the fungus spores and certain weather conditions of low wind and high moisture. Rain or snow followed by a warm spell could get the spores going. Also, contamination by tools or handling could spread the fungus spores onto the plant.

Not a real easy cure ...only treatments. I may dig it out of the pot; leaving the Opuntia polyacantha while bringing the E.tex. indoors to dry out a month or so in much lower humidity than outdoors. It's a favorite of mine and I'd hate to lose it. But then ALL of them do die...eventually.

Here she is in 2020 and 21 during the blooming phase.
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Download
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Re: Is this rust or frost damage?

Post by Download »

I'm going to have to disagree about cures. Some of my cactus got rust over winter, but it went away with drier weather in spring plus mancozeb fungicide.
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mikethecactusguy
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Re: Is this rust or frost damage?

Post by mikethecactusguy »

Hey Steve-O
I'm not the biggest fan of pesticides, but with 764 plants in the collection I will occasionally resort to using one if it means saving and preventing an outbreak in the collection. I look at it this way. The once or twice a year use to treat a single plant is not going to contribute to the decline of my eco-environment Try a fungicide. If it is rust, it will stop it, The plant will always be stained. I'm not a fan of watering down all the plants with a pesticide yearly like some do. I recently bought 3 different bio-friendly treatments. In a few weeks I will water down the collection with those.
Mike The Cactus Guy
Enjoying the Spines
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ohugal
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Re: Is this rust or frost damage?

Post by ohugal »

I also have my doubts it is sunburn. Especially if you haven't moved the plant and at this time of year.

@mikethecactusguy: can you expand on your biological treatments?
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
south-west facing window in a city appartment
min. winter temp. 16°C/60.8°F
no outdoor or winter rest capability
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mikethecactusguy
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Re: Is this rust or frost damage?

Post by mikethecactusguy »

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The Cyzmics is the more dangerous one. It's going to kept as a last resort if I have any issues. I like it because it will hold up under the high heat of the desert here.
Mike M
Mike The Cactus Guy
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Download
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Re: Is this rust or frost damage?

Post by Download »

mikethecactusguy wrote: Sun Mar 06, 2022 12:48 am 20220305_163442.jpg
20220305_163452.jpg
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The Cyzmics is the more dangerous one. It's going to kept as a last resort if I have any issues. I like it because it will hold up under the high heat of the desert here.
Mike M
Rust is a fungus, not an insect. Insecticide won't kill it.
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ohugal
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Re: Is this rust or frost damage?

Post by ohugal »

The first one I know, never heard of the other two. I did just read the Wikipedia page on Spinosad. It is very toxic to bees, rainworms, fish and aquatic organisms. You water down your plants with this at night?
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
south-west facing window in a city appartment
min. winter temp. 16°C/60.8°F
no outdoor or winter rest capability
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Steve-0
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Location: Salt Lake Valley, Utah...high mountain desert climate

Re: Is this rust or frost damage?

Post by Steve-0 »

I'm using Copper Sulfate spray and hope that and approaching warm weather will knock it out. Two applications so far and another this afternoon.
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ohugal
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Re: Is this rust or frost damage?

Post by ohugal »

Good luck!
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
south-west facing window in a city appartment
min. winter temp. 16°C/60.8°F
no outdoor or winter rest capability
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mikethecactusguy
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Re: Is this rust or frost damage?

Post by mikethecactusguy »

I never water down my plants. When I apply any type of insecticide it is a very controlled application. Surface application is through misting only. Soaking the plant surface in the early morning just around sunrise so that the plant absorbs the treatment. If I have to treat a plant through the roots, I will remove that plant from the greenhouse, place it on a collection mat and then soak the soil. I don't just treat all 760 plants as a precaution. I keep an 18" fan located just above the greenhouse door, running 24hrs a day. After a watering I supplement that with a12" fan located just above floor level also by the door. I learned that air circulation is key to preventing most issues. No fungus, rot etc. As for pests, I have been very lucky to not need a to do an all out treatment of both the greenhouse and surrounding grounds. I leave spider webs intact. Very rarely do I find any intruder in the greenhouse. 2 to 3 hrs a day just examining all the plants also helps. Copper Sulfate and sulphur are really the only treatments I have had to use over the past 3 years. I keep everything else around just in case. I am more inclined to throw away a infested plant, then chance a spread. I have 12 Teddy Bear Cholla cutting that I was rooting sudden come down with mealies. It happen fast, Attacked all but 2 cuttings. I threw them all away.
Mike The Cactus Guy
Enjoying the Spines
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