Catasetum Rot HELP! - Orchid Board

mab3362 · #1 08-12-2010, 11:39 PM

I have had catasetums/cynoches/etc. for 6 months or so with no problems. Recently I have had 3 plants, simply rot overnight! I am not sure the cause.

Growing conditions: outdoors under covered plastic roof with 50% shade, hanging, with constant circulation from fans. Outside temp has been 100 this last two weeks, in this "greenhouse" temp has been about 10 degress cooler and plants are nots hot to touch. Since they are semi outside and its been hot, I have been watering nearly daily as they quickly dry out. Additionally, misters com on during the day to cool the area off some more. Cattleyas are thriving in this similar situation.

Catasetums are potted in plastic with sphagnum with styrofoam nuggets (per advise from Fred Clarke).

Any thoughts? The ones that rotted, I have pulled off any intact non rotted pseudobulbs and removed all media and brought them in house bare root and sprayed them with dilute physan. Was thinking about letting them dry for several days in the open air and then repotting in fresh media.

Would love to hear what you guys/gals think!

micah

Eyebabe · #2 08-13-2010, 12:19 PM

The only thing I know of that rots a plant that fast is Pseudomonas...although Pythium fungus can rot stuff pretty quick too. Anything else would take longer than a day or so.
Don't know a wet lick about cultivating Catasetums though

Izzie · #3 08-13-2010, 12:37 PM

I'd agree with eyebabe...

Can you get pictures to post? That might help narrow it down. What did the media look like when you unpotted?
Have you checked all the other plants in the area where these guys were?

mab3362 · #4 08-13-2010, 12:48 PM

Media is fresh and clean. They simply turn soft and squishy, and the leaves fall off and the pseudobulbs flop over. They don't turn black or anything like that!

Izzie · #5 08-13-2010, 01:02 PM

That is very concerning....pictures would definitely help.

King_of_orchid_growing:) · #6 08-14-2010, 04:00 AM

The moss might be the culprit.

Of all the pics I've seen of Catasetums growing in the wild, they don't appear to be growing on trees with moss.

The trunks may be wet, but there's no moss.

kavanaru · #7 08-14-2010, 07:47 AM

Normally, the media should not be the problem here... Catasetum love A LOT of water when growing (I grow all my Catasetinae in S/H and I know people growing them in standard substart, but the pots sitting on pans with up to 2 inches of water!) If the PBs of your Catasetum were already mature, which I am not sure should be the case yet (but maybe your plants just started too early to grow), then too much water can become a problem.... Please be advised that Sphagnum can look dry on the top, but be wet inside! A lot of people grow them succesfully in Sphagnum, Fred Clarke included (at least the younger plants!)

Temps should also not be a problem at all... Cold Temps can kill Catasetinae when in active growth, but when dormant they can stand very low temps if kept dry. On the other side ofthe scale, Catasetum can stand temps of over 100F if enough water is given...

On the other hand, I have right now a Catasetum incurvum, which is still dormant (newly imported from Brazil) and has started to rot with no apparent reason (it is in Sphag and completely dry!)

Pictures of your plants and growing area could help to identify the problem. Exebabe has already given a good point about quick rot!

Lagoon · #8 08-14-2010, 07:49 AM

Micah, Get you get us some photo's?
Are you seeing the old bulbs die out along with the root system? Older bulbs will turn yellow and go soft.
Do you have any new growth this season that green at all?
Man, that is some high heat you're dealing with!

mab3362 · #9 08-15-2010, 10:55 PM

Hi All,

Thanks for the replys, these are the only pics I could find. When I saw it happen to my 3 mature plants, I freaked and pulled off the old pseudobulbs and dunked them in physan! I think the old bulbs will be ok and I am potting them up in dry sphagnum and will withhold water to see if i can stimulate a new growth.

When looking at these picks, the new growth is literally mush, you can see it is bending over. The old bulb, on this one is still solid, but on the other plants I lost, they looked normal but again, pure mush when you squeezed them. All my other plants, about 10-15 are all still doing fine, perhaps and isolated incident, but one I would sure like to avoid!!
Micah

catasetum-ian · #10 08-16-2010, 09:23 AM

well i usually don't attempt to replant a pseudobulbs that i just rescue from rotting problem immediately, in fact i would just trimmed off all the roots and let them sit in an empty pot under dry condition till new shoot appears from the back bulbs.
just had a similar case like your to one of my catasetum longifolium a month ago and the good news is new growth started to appear from the rescued back bulbs