Dendrobium laevifolium spots on leaves?

[jason woodrue]

Hi,

My Dendrobium laevifolium has spots on the leaves. all the leaves seem to be affected by this to varying degree. Am i growing to warm? Humidity too low?

sometimes the black little spot is a depression and sometimes it is raised - almost looking like black scale, but more often it is sunk into the leaf. i have tried to remove the raised bumps but they do not come off. it kindof reminds me of how some oncidiums are prone to leaf spotting.
Other than the spots, the plant seems fairly healthy and is putting out nice new growths!

your thoughts?

[jason woodrue]

Tom-DE what conditions are you growing your laevifolium?

[Tom-DE]

I/C but it can handle warmer. I used to grow both clones of mine in moss but now I grow them on cork mount with little bit of moss. IMO, it doesn't like constant wet.

[whygreenberg]

Jason...my laevifolium is also prone to getting these black spots on the leaves. not really positive as to why (i don't mist or anything, and my growing shelf gets really good air movement,) but i can say that it really hasn't affected my plant at all.

in terms of growing conditions, mine are pretty much I/W, and in the summertime here in NYC, highest temp can get up to 84º F. mine is in sphagnum moss with some small gravel mixed in.

interesting what Tom says about not growing constantly moist, b/c that's what i've always read is best. but seeing all the awesome 'chids that Tom posts, i bow to him.

[whygreenberg]

Ha ha! Funny, Jason...didn't see till just now that you are in NYC yourself!

[catwalker808]

Tom. I 've got to disagree just a wee bit about the temp range. I think that I/C is entirely suitable for cuthbertsonii, however, laevifolium is a bit warmer. Laevifolium will surely tolerate cool (it may even experience cool in its habitat). However, I think that it really thrives in the range between 50F and 75F ... if you can give sufficiently bright light in the lower temp periods.

The normal cycle for the species is active growth during the bright light late spring to early fall. Then in late fall/early winter, the leaves drop off in response to sub 50's temps and low light conditions. Then the bare bulbs bloom in spring, followed by new growth in late spring.
I have found that even in above 80's summer temps, if plants are heavily shaded they will experience good new growth. In addition, IF you can give them strong light when temps hit the low 50's , the plants will not go deciduous and will bloom with full foliage and even new growths.

Tom. your plant is blooming with full foliage (in mid summer) so you must be able to somehow provide the lower temps even when it is very bright and hot outside. For growers like yourselves in temperate zones, it may be more difficult to achieve any winter growth. In temperate zone low light winters, the plants look like a cluster of smal dried round onions.

Attached is a photo of a plant I bloomed probably in mid Feb. with 52F to 75 temps and very bright light.

Jason. I agree with Tom about the potting. Your sphagnum might be keeping your roots soggy since they are thin clinging roots rather than fat feeding roots. Don't look at the flowers in my photo just look at the leaves and pbulbs. Your leaves look a little translucent and soft. At this time of year they should be firmer and maybe even a little bit more reddish, even with the new growth. You might even have low light with too warm temps. But the pbulbs still look good and should harden off ok. The leaf spots are probably from stress ... like zits just before the senior prom.

[jason woodrue]

Hi,

thanks Tom, Greenberg (bkln), and Catwalker. all your input is fantastic.

By the way my laevifolium has the J&L sphag, treefern, perlite combo. It seems to dry out about everyother day in current NYC weather. We've been in the 90s the last week and all orchids are just gonna have to grow hot at my place until things cool down (no AC in growing areas). So it sounds like the spots may just be a response to conditions. Tom your plant looks great! Catwalker, Yours looks great too! but i see yours has some spots also. maybe this species genetically prone to do this? I guess it doesnt matter a whole lot - it is supposed to be deciduous unless you grow it the way catwalker was talking about. I will see if I cant move the little plant outside, up the light and give cooler nights... In the winter I am able to grow under cooler conditions with a with fluorescents and daylight supplemented enclosure. it is too hot to use the enclosure in the summer. All orchids are extra-vehicular right now. In the tank they just boil

MIke Smith

[Tom-DE]

"Tom. I 've got to disagree just a wee bit about the temp range. I think that I/C is entirely suitable for cuthbertsonii, however, laevifolium is a bit warmer. Laevifolium will surely tolerate cool (it may even experience cool in its habitat). However, I think that it really thrives in the range between 50F and 75F ... if you can give sufficiently bright light in the lower temp periods. "

Catwalker, it all depends on your definition of I/C. Yes, it basically is an intermediate grower, but this species is from 400 to 2400 meter alt., so it can handle wider range of temperature and that is why I said I/C but it can handle warmer temperature
My definition of I/C:

Intermediate(I) 55-80F
Cool(C) 50-70F
Warm(W) 60-90F

I am not going to define cold or hot, you should get the whole picture now.





"Tom. your plant is blooming with full foliage (in mid summer) so you must be able to somehow provide the lower temps even when it is very bright and hot outside."

All the flowers on my plant are from leafless pbulbs. It normally starts to bloom in mid/late May and the flowers last for four months under my condition. I don't grow this one outside. The high temperature in my inside growing area is not more than 75F.

" For growers like yourselves in temperate zones, it may be more difficult to achieve any winter growth. In temperate zone low light winters, the plants look like a cluster of smal dried round onions."

Both of my plants don't grow(much) during the cooler months and they drop off some leaves, which it is normal. This species blooms on leafless canes...

"Attached is a photo of a plant I bloomed probably in mid Feb. with 52F to 75 temps and very bright light."

Hmm, that is called intermediate temperature in my book.





"Jason. I agree with Tom about the potting. Your sphagnum might be keeping your roots soggy since they are thin clinging roots rather than fat feeding roots. "

Moss can be used but you have to keep your eyes on the moss condition. Water your plant when the moss is crispy dry at the surface.
Here is photo of my plant(same plant posted on other thread before I divided and mounted this spring) that was potted in moss: