Ctna 'Why Not' sick leaves
 

Hello everyone,
My sick catt is Ctna "Why Not'

Could you please tell me what seems to be traveling down one of the leaves from the tip? Very obviously, the leaf coloration is yellow-ish/orange-ish/brownish with black spots (I included a photo of the underside, as you can see). The black spots are somewhat indented and seem to be firm. The other discolorations are not indented and also seem to be firm, no mushiness. In fact, they seem to be as firm as the green, healthy-looking portion of the leaf. Although I noticed the leaf problem earlier in the week, it may have gotten slightly more discolored, definitely in the last 24-36 hrs. I would have already contacted you, but I've been sick for several days. I've managed to water my mounts and check my orchids each day, though - but not feeling so great, I failed to closely monitor how rapidly/slowly the problem changed from day to day earlier in the week.

Two of the other green leaves are also showing 2-3 indented dark spots at the tip, but no other discolorations.

Several months ago (I failed to make a note of the exact date) I was concerned about the smaller black indented dots on several of the green leaves, so I sent a sample to Critter Creek and the report that they sent to me afterwards indicated the plant was negative of any virus.

I repotted the plant last month and at the time only the leaves with small-ish, slightly indented dark spots were obvious.

Thanks to all of you for reading…..I would appreciate your help.
Vicki

By the way, the plant has a spike about 2" long.

Seems like some sort of fungal infection to me.

Hopefully someone with more knowledge can chime in.

http://www.google.ca/url?sa=t&rct=j&...70810081,d.aWw

(page 25) Bacterial Brown Spot. Acidovorax (syn. Pseudomonas).

Prevention: Pseudomonas cattleya is a water-borne pathogen that prefers warm, moist conditions. Reduce humidity and temperature (if possible), eliminate overhead watering and increase air circulation.

Treatment: Immediately remove infected tissue and spray the plant with a bactericide like Physan or copper compounds following label instructions. Disinfect growing area with 10% bleach solution.

Bingo. Very nasty stuff. Looks like you have a good collection so disinfect everything. I would get a pump sprayer and spray everything down. If not, you can just cut off the infected leaf and dab powdered cinnamon on the cut with a Q-Tip. I get this all the time and that's what I do. But then again, I don't water overhead. I get no water on any of my leaves. I just water the media.

RandomGemini
 

Thanks for replying!
Vicki




---------- Post added at 04:37 PM ---------- Previous post was at 04:32 PM ----------

Thanks for taking time to look the info up for me! I should have thought to do it myself. :blushing:
Vicki






---------- Post added at 05:13 PM ---------- Previous post was at 04:37 PM ----------

Hi James,

After reading your advice, I did a total disinfect of the entire greenhouse. As for that one particular plant, I did cut the leaf off and apply cinnamon to the wound. Afterwards, I treated the plant with Thiomyl. I know the bottle says it is a fungicide, but it was the only "big guns" product I had (I used it on a fungus infection late last summer). I hope Thiomyl was ok for this ??

I don't water overhead, but I do mist my mounts heavily with a pump sprayer and have a misting system, as well, so moisture may have accumulated on the leaves of this plant too much - so I plan to re-think the water overspray issue. It's very hot here in Alabama at this time of year. My greenhouse is like a furnace. I'm doing my best to keep the temp. down as much as possible, but unfortunately, I haven't mastered that yet (not sure if I'll ever be able to). The airflow seems to be good, the humidity from 55-65% during the day.

Thanks for your help,
Vicki

If you can water the floor of the GH and run big fans along with your misters, that should drop the temps some. The RH is high so maybe you don't need the misters. Hard to get evaporative cooling with high humidity but with good strong air flow you might drop the temp by 10*f.

I agree with this advice, plus, I would spray the whole plant with the 10 % bleach solution. I have used this and it works! BettyE.

James Mickelso
 

Hey James...
"Been there, done that". Minimal luck, unfortunately. You're right, though. Your thoughts do work for me. Watering the floor does drop the temp. a tiny bit, but not enough to call the temp. decrease significant. Definitely not 10 degrees. I'm one step ahead of you (I think ??)...watering floor, misters, 4 fans (a small one sitting at the end of each bench (that oscillates), a large one on the floor under each bench)...even Port-O-Cool swamp cooler - and that fan is strong. Exaust fan, overhead vents. Geez, I'm at a loss....I must be doing *something* wrong. Whatcha think?

The floor is treated wood except under the benches. Under each bench, there is river rock instead of wood. My mister line is floor level, attached to the bench legs/braces and mist across the rock toward the walls. If I don't have the misters on, for whatever reason, I water the rock with a garden hose. Think I should omit the misters?

I made notes for an example of temp. and humidity at 3:00 pm today: 91 degrees outside, 96.5 in the greenhouse, 62% humidity outside, 61% in the greenhouse. I brought one of my favorite cattleyas inside, otherwise the blooms are gonna wither and die before their time. Sad but true. :(

I’m grateful for your help, but I sure would appreciate more please.gif All suggestions welcome...you and/or anyone. Thanks.
Vicki

I had pictures to include, but they wouldn't upload. I've only had this problem once in the past. I sent a msg. to an administrator, but there must have been a problem because I never heard back. The error msg. said: Your submission could not be processed because a security token was missing.

If this occurred unexpectedly, please inform the administrator and describe the action you performed before you received this error.
Do you know what it means?




---------- Post added at 04:26 PM ---------- Previous post was at 04:20 PM ----------

Thanks, Betty. I didn't know about the bleach treatment. I've already sprayed it with Thiomyl. Should I spray with bleach also?

I was just typing to James about the heat problem I'm having. Since you and I have the same style greenhouse, are you having issues with the same things...or not? I hope not!

Thanks again for your advice,
Vicki

I don't have a g/h but my g/h friends all tell me the same thing...if the humidity is high their cooling equipment can't cool the space very well.

How big is your g/h?

You might want to post up a separate thread in the g/h section so other g/h growers can share what they do to combat extreme heat.

And there is why you can't cool it with evaporative cooling. The RH is high so the is little evaporation. For $100 HD has a nice little unit that cooled my darkroom during the summer down to 60*f if I left it on high. Might work for you. give it a try.