BLACK PATCH ON LEAF CATTLEYA ORCHID

[monet]

Hi
I have a black patch on my orchid leaf. I have cut back twice with sterile knife and applied cinimon to the area and tried sulphur powder. It has come back. I have a flower bud developing should I cut back and loose the bud? Thank you if you can help.

[silken]

I would hate to lose a bloom, but if it keeps advancing, it might be better to take more drastic action. Have you always cut into clean green tissue when you cut it back previously? If so and it is still advancing, in order to save the plant you might need to remove further down. It can always bloom another time. Try cutting and using some rubbing alcohol on the cut this time, since sulfur and cinnamon didn't do the trick.

[monet]

Hi Silken,
I did cut into heathy leaf but it reurned. I will get some rubbing alchhol tomorrow and cut a little bit lower and hope.
Thank you.

[silken]

Be sure to isolate it from other plants as well. I hope it quits advancing. You may have to cut further than just the adjacent healthy tissue. Sometimes it can be in the green tissue, but not apparent yet. I had an Oncidium that had a similar problem. I removed the unhealthy pseudobulb plus some healthy green rhizome, 2 or 3 times and it kept returning. I had to remove the entire next healthy looking pseudobulb before I could finally eradicate the problem. Needless to say I had to wait several years for it to get large enough to bloom again. But it is blooming right now

[Orchid Whisperer]

Cut using a very sharp blade (such as a single-edge razor blade or an X-acto knife.). I would wipe the leaf with alcohol or peroxide before cutting.

After cutting, either discard the blade or flame sterilize blade until red hot before you use it again.

[Leslie]

It has happened to some of my cattleyas and I attributed it to high humidity and some type of bacterial infestation. I usually cut the part off about 0.5 to 1 cm below this black part with sterile cutters and spray with 3% hydrogen peroxide. This usually stops it. If it continues I will keep cutting until it stops.



The above pic shows the cut part that grew a sheath in the growth nonetheless. I had to cut this leaf twice.

I also increase air flow a bit and made sure leaves are dry by nightfall, that means no spraying after 2 pm (under lights).

Hope this helps....



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[monet]

Originally Posted by Orchid Whisperer

Cut using a very sharp blade (such as a single-edge razor blade or an X-acto knife.). I would wipe the leaf with alcohol or peroxide before cutting.

After cutting, either discard the blade or flame sterilize blade until red hot before you use it again.

Thank you orchid Whisperer, I have treated and hope this works the bud is growing well and I see 2 more flower spikes coming on. It is the first flowering so cant wait to see it.

[Leafmite]

I am glad you did not lose the flowers. I have had this happen now and then when I did not give my Cattleyas enough Calcium and we had a cold, wet summer. Your Cattleya should be fine.