OOps, brown spots on my dend.

[renata]

Helloooo!
My dendrobium (nobile type, I think it is a Yukidaruma) is very healthy with lots of canes, but there are lots of brown spots on the tip of the leaves, especially the new ones...
The plant is in plastic pot and bark/charcoal mix, but it's under full sun, could it be sun burn or some disease??? It's sitting on a glass table, could it be refflecting on the leaves, cause there are spots under them as well...
Take a look at the pics,
Thanks so much for your help!!!

[kid a]

Well unfortunately I have no idea. But.... I don't think it's sun burn just because they are all mostly the same shape and seem to have an area in the center of the spot that is a bit different than the rest of the spot. I am thinking it is something along the lines of fungus/bacteria/disease. Hopefully someone will know and you can get it all fixed up. Good luck!

[GrowInHydro]

Do you have a 4 year old with a magnifying glass...



Seriously...it looks like it could be rot form water staying on the leaves. If it doesn't get worse, don't trouble yourself over it. Orchid leaves get ugly sometimes.

[mrspiza]

My Dendrobium nobile has the same thing going on. I asked about it when I was at Hausermann's last week, and they said that this was natural leaf drop in the fall, and that unless it was happening to the new shoots I should not be concerned. On mine, anwyay, the black spots at the tip are restricted to the tips of the older leaves. They said that this often freaks out people new to nobile-types.

[mrspiza]

Hmm, I just read that it was on the new ones, too. Hmmmmm. This pattern is exactly what's on mine. Whatever it is, we have the same thing. I'm a little concerned about my plant now . . .

[GrowInHydro]

If you guys are really worried, here is more info: Plant Disease 1984 | Greasy Leaf Blotch of Dendrobium nobile Caused by Aphelenchoides besseyi.

Watch your watering, and really, don't fret too much. The leaves are going to drop here in a few months anyway.

Kind regards,
Jesse

[kid a]

I live not far from mrspiza. I don't think we have nematodes in Indiana at lest that I know of. I couldbe wrong but I think is from something different

[renata]

GROWINHIDRO, maybe you're right, we tend to worry about a little bit too much, but i'll just keep an eye on it and cut the affected parts...
MRSPIZA, if you have any news, let me know...also if your try a successfull treatment, maybe I will too...Is your plant ok, despite of these spots? Cause mine is and has doubled its size in half an year, but appered this spots on it....and I got worried....
Well, KID A, I never heard of nematodes here in Brazil too, I'll pray it has nothing to do with this .....
I'll bring any new information, ok?
Thanks a lot, everyone!!!!

[Brooke]

Nematodes are everywhere Kourtney, even in IN :>) If the nursery where purchased has them, then they can spread via splashing water. If a division is from a friend and the plant was outside, splashing water, including rain can spread the nematodes.

Brooke

[GrowInHydro]

Hi RENATA,

Unfortunately you do have Aphelenchoides besseyi in Brazil, but it is more commonly hosted by rice and strawberries.

I think you are fine. Just be careful when watering and assume it is infectious and take precautions not to spread whatever it is to you other orchids. According to the literature you will know for sure within 3 months if it is a nematode, but it may very well just be bacterial brown rot. Since nobile types are deciduous, you're leaves will drop and the problem should go away with the onset of winter.

Kind regards,
Jesse

EDIT: Hi from Lexington Brooke!! Nice weather we're having huh :-)

[renata]

JESSE, how will I know if it is nematodes? the plant will die in 3 months, hehehe...????Oh, God, I hope not!!!! I've already separated this poor thing from other plants as you said, let's see what happens now, ...thanks for everything once again!!!!!!!!!

[GrowInHydro]

Originally Posted by renata

JESSE, how will I know if it is nematodes? the plant will die in 3 months, hehehe...????Oh, God, I hope not!!!! I've already separated this poor thing from other plants as you said, let's see what happens now, ...thanks for everything once again!!!!!!!!!

Nematodes won't kill your orchid, but it will weaken it and a secondary infection or other pathogen might.

You won't be able to see if you have nematodes with out a microscope. But, visible symptoms include wilting during the warmest period of the day, chlorosis, and stunted growth.

[Brooke]

Hi Jesse

Yeah, great weather - too bad Fay didn't give us rain to go with our mist.

In regular garden plants, hosta in particular, you cut off a portion of a leaf, soak it in a small amount of water and then check the water under a microscope or 10x loupe. The nematodes will be little wiggling, almost transparent worm-y things.

Splashing water is the biggest culprit in the spread of nematodes. If it was my plant and I suspected them, I would destroy the leaves as they drop from the plant. They will live in the soil from year to year. Will they live in an orchid mix - I don't have a clue.

Brooke

[mrspiza]

If Renata and I have the same thing on our Dens, and I think we do, it cannot be nematodes as my Den has been isolated from all other orchids the past year, and none of them have it. Also, I never let any water get on my leaves.

[jerrymeola]

The leaf is definitely infected with something. Cut the leaf. That should eliminate the current problem. Nobile drop their leaves and can survive with almost none. By the way this is the time to stop all fertilizer on Nobiles or they may not flower.

Spotting and browning is normal as Hauserman's told you but this pattern is not normal leaf age. Also you said this is on the new leaves.

I do not see where this thread went into nematodes, but nematodes are a soil infestation that usually attacks the roots. The best cure for nematodes are nematodes. There are beneficial nematodes that destroy the harmful ones. They can be purchased for large agricultural treatment and already are present in Worm Tea. Anyone using Worm Tea regularly will not have a nematode problem. The pattern on the leaves of this plant is not typical of nematodes.

Different growing conditions may be necessary if this continues. Good air circulation will help. More sunlight will sterilize the infection. Nobile do not need shade and can take full summer sun without shade.

[Brooke]

Here is a link describing foliar nematodes that explains them and their transmission

Foliar nematodes - Wikipedia, the free encyclopedia

I love ferns and had originally planned to have ferns growing under my benches in the g/h. After learning they are very suceptible to nematodes, I decided against it. They are beautiful, would help with humidity but the danger, to me, was to great to introduce into my g/h floor.

Jerry, Renata lives in Brasil and it is the spring season for her and the Den. is not getting ready for dormancy.

Brooke

[kid a]

nemadtodes are everywhere? Now I am paranoid, lol!

[mrspiza]

Yes, microscopic nematodes are very common in soil and elsewhere. In fact, they are one of the most numerous forms of life on the planet, and can be beneficial or detrimental--like bacteria. And much like bacteria, without them, we surely would not exist. So give them some respect. :-)

[mrspiza]

But back to the point, this particular problem is almost certainly not nematodes. I just noticed today that one of my new Den. nobile hybrids has a couple of the spots as well. It has never been in contact with the other one, which is now sequestered outside and seems to be doing quite well despite the black spots, which don't seem to grow more than about 4mm across.. I cut the spots off the "newly affected" plant but left them on the original. Guess I'll see what happens!

[jerrymeola]

This should be the end of flowering season in Brazil.

With lots of canes and leaves, it would appear the plant has not adapted to the southern hemisphere.

Still removing the leaves is the best defense to fungi and bacteria infections. Nobile can survive with little or no leaves not just when they are dormant. And if it is a Yamamoto Den it never goes dormant.

[renata]

MRSPIZA, I also think it's not nematodes, but bacterial infection, look at this site:Fitopatologia.net - herbrio virtual
It looks like this pic of "mancha bacteriana"= bacterial spot...
They recommend more ventilation, avoid water on the leaves, cut affected parts and spraying antibiotics containing copper...Now we have to find it....

JERRY,
My dend should be blooming but is not....it's a shame but I think I fertilized it for too long...Not a single flower...It's sure they are stressed out by the dry weather, yesterday humidity was the lowest of the year, 13%!!!!!!!!!!
Just can't avoid the old canes from shriveling...
On the other hand, the plant is gorgeous, many new canes, I'll have to repot it asap...
I'm cutting off the tip of the affected leaves, as you said...it's safer...
Can this Dend be a Yamamoto? How can you tell?...
Thanks everyone!