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Old 08-27-2017, 10:36 AM
monet monet is offline

Join Date: Aug 2009
Posts: 81
Black Rot? Female

Originally Posted by dounoharm View Post
akkk! looks like too much water to me, and possibly contamination from something....I would open up that root ball, cut off everything with sterilized scissors or knife....

I would mix up some fresh physan and spray everything you are going to use on the plant, including the plant, I said before, open up the root pot bound cases like this, I just cut in 3 places, about an inch from the plant, straight down with my knife. worry those plant roots loose and see whats in the might have an unseen problem inside there.....get all the cut and dead roots out and loosen up the rhizomes so you can see it all....cut the damaged portions out.

then, just lay the dissected plant on some newspaper to dry out some....rot is wet, right?....spray every couple days with that physan you mixed up....
do NOT leave it in strong light while it is 'healing'...put it in a shady spot....

after about a week, you can see if it is spreading or not....if it is, just keep cutting till you finally get to the end....orchids can take months out of a pot!

when it starts new growth, and that is clean of rot, just place it in a clay pot, no medium for a couple more weeks....

its a long process, but you should be able to rejuvenate it.....but recall how it got to be that way and adjust your watering....maybe less often? and with fresh water....

cattleyas really like to dry out between waterings, and when you have such a tight root ball, it is probably still wet in the middle when the outer roots look dry....this is why you repot every year or two....

just my 2 cents, good luck!
Thank you for the advise. I have to try and find a Orchid fungal disease control. The plant has has some good new roots and shoots. You mentioned calcium how do you apply that in what form?
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Old 08-27-2017, 10:51 AM
Orchid Whisperer's Avatar
Orchid Whisperer Orchid Whisperer is offline
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Join Date: Jul 2012
Zone: 7b
Posts: 3,061
Black Rot? Male

Two good calcium sources.

1 Easiest to find - either pelleted lawn gypsum or plaster of Paris (last one sounds crazy, right??). Plaster of Paris is just gypsum (calcium sulfate) with some water driven off (which you put back in when you make plaster). With either form, mix a teaspoon per gallon of water. Allow to dissolve overnight. Add about a cup of this solution to a gallon of water applied to plants alternating weeks with your regular fertilizer. If you also want to provide magnesium, add a teaspoon of Epsom salts (from the Pharmacy) into the stock solution with the Gypsum.

2 Found in specialty garden shops - calcium nitrate (sold to help prevent blossom end rot in tomatoes). A quarter teaspoon per gallon of water.

Either of the above options is way cheaper than commercial CalMag products (which work, but are expensive).

Another active thread right now is for an orchid fertilizer called Orchidgain. It has calcium. I would only mix that fertilizer at 1/8 to 1/4 tsp/gallon though.
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Old 09-03-2017, 12:31 PM
monet monet is offline

Join Date: Aug 2009
Posts: 81
Black Rot? Female

Thank you all for your advice. I am carefully removing the black spots and sealing the ends with rubbing alcohol . I did not know about calcium for preventing decease. Also letting the plant dry out. Not found fungus Treatment yet.
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Old 09-04-2017, 02:20 AM
camille1585's Avatar
camille1585 camille1585 is offline

Join Date: Oct 2007
Location: middle of the Netherlands
Posts: 12,236

I wouldn't be surprised if you didn't find a systemic fungicide. If the UK is anything like other EU countries, all the effective chemicals treatments (i.e. all the systemics and a lot of everything else) are getting pulled from the consumer market to protect the environment.

It's getting increasingly difficult to buy "big guns" to treat anything. I had a look at the alternative natural treatments that are now filling the shelves, and the only insecticides are basically pure rapeseed oil sold at a ridiculously inflated price...

Completely orchid obsessed and loving every minute of it....

My Orchid Photos
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Old 09-04-2017, 06:22 AM
monet monet is offline

Join Date: Aug 2009
Posts: 81
Black Rot? Female

Hi Camille, Thank you for reply. We must protect the bees but hope for safer remedy that wont cost so much . I am watching and cutting out any black spots out. An amazing amount of new roots are growing. Love the pictures of your orchids such variety of colors and shapes.
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