# Copper for slippers



## dodidoki (Jul 24, 2011)

Hello! Previously I had many problems with Erwinia, fortunately in last two years I didn't met this disease. However I read some literature and they recommend copper against bacterial infection. Has anybody experience with copper?
Thanks for replies!


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## Rick (Jul 24, 2011)

There is a product called Phyton that is copper sulfate as primary active ingredient. It's almost like a black paste. Some people swear by it, I didn't have that much luck with it.

I found the company trial studies and noted that the success rate for non orchid plants was better than doing nothing, but not very good. Really just a few percent better than doing nothing. I would not call this product very effective.


In comparison I found an article (for non orchid species) that showed that excesses of potassium (relative to calcium an magnesium) where much more positively correlated to incidence of Erwinia. Also the susceptibility to Erwinia increased dramatically when leaf tissue concentrations of K exceeded Ca and Mg tissue concentrations. Obviously changing fertilizer will not "cure" a plant with an active infection, but "an ounce of prevention is worth a pound of cure" as they say. So I would try to push your general plant nutrition away from high potassium fertilization.


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## Brian Monk (Jul 24, 2011)

I have used copper on Paphs with no problems that I have seen. Don't se it on your Dendrobiums, especially anosmum and its relatives. I can't stress this enough.


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## dodidoki (Jul 24, 2011)

Rick said:


> There is a product called Phyton that is copper sulfate as primary active ingredient. It's almost like a black paste. Some people swear by it, I didn't have that much luck with it.
> 
> I found the company trial studies and noted that the success rate for non orchid plants was better than doing nothing, but not very good. Really just a few percent better than doing nothing. I would not call this product very effective.
> 
> ...



Dear Rick!
Thanks for your very useful reply. My opinion is similar just I didn't know reasons. While I use added lime stone in mix and use as fertilizer so called "compost tea" with high Mg concentration, Erwinia diappeared, and I haven't met it for about 2 years. 
I open this thread, because all of my plant infected by erwinia previously, died within a week despite of my all efforts (peroxide, dry condition etc.) and a few days ago I read this oppurtunity about copper against bacterial infection.
Best wish: Istvan


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## John Boy (Jul 24, 2011)

Hiya Rob!
would you mind showing a few pictures of your Erwinia expiriance??? Some people might not even know what Erwinia means!


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## Rick (Jul 24, 2011)

dodidoki said:


> Dear Rick!
> Thanks for your very useful reply. My opinion is similar just I didn't know reasons. While I use added lime stone in mix and use as fertilizer so called "compost tea" with high Mg concentration, Erwinia diappeared, and I haven't met it for about 2 years.
> I open this thread, because all of my plant infected by erwinia previously, died within a week despite of my all efforts (peroxide, dry condition etc.) and a few days ago I read this oppurtunity about copper against bacterial infection.
> Best wish: Istvan



I still have much better results with dragons blood and cinnamon than I every had with Phyton 27. I still see occasional Erwinia, but now if it pops up, its much slower (less virulent) in expression. Often I just chop off the effected leaf, and cover with DB and cinnamon, and good to go. Since I've been pushing my whole collection over to higher Ca/Mg gradually for the last couple years, and just recently figured out the competitive K interaction, I expect to see even lower rates and less virulence. In some recent cases, I've seen it run its course on an old phrag growth while putting up a new growth, and never spread beyond the outer leaves of the old growth with no intervention at all. 

It's also not unlikely that people with good results on Phyton where treating plants with this low grade version of Erwinia, for which probably anything would work just fine.


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## Roth (Jul 27, 2011)

Rick said:


> I found the company trial studies and noted that the success rate for non orchid plants was better than doing nothing, but not very good. Really just a few percent better than doing nothing. I would not call this product very effective.
> 
> In comparison I found an article (for non orchid species) that showed that excesses of potassium (relative to calcium an magnesium) where much more positively correlated to incidence of Erwinia. Also the susceptibility to Erwinia increased dramatically when leaf tissue concentrations of K exceeded Ca and Mg tissue concentrations. Obviously changing fertilizer will not "cure" a plant with an active infection, but "an ounce of prevention is worth a pound of cure" as they say. So I would try to push your general plant nutrition away from high potassium fertilization.



Not very surprised. In Thailand, to control pseudomonas during the rainy season ( where they leave sometimes the paphs outside below just shadecloth, so they get full rain...), they use huge amounts of lime, including on the leaf bases and crown.

As an aside note, at a time where Vacherot and Lecoufle was a world class nursery, and one of the leader in orchids, they used extremely hard water, 1g/L fertilizer, and used Kocide 101 at full strenght every week. They had everything possible in those days (from cyrtochilums to dendrobiums, through masdevallia, paphios, miltoniopsis, odonts, phals, catts...), everything got Kocide, including during hot summers, and the plants were superb. I know people who killed everything with copper compounds on the other side. So it must be the growing environment that allows people to use or not Kocide.


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## Eric Muehlbauer (Jul 27, 2011)

I've tried Phyton. Can't say it ever helped in any way.


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