Dendrobium Emma White- black spots + yellow leaf

[Stefka]

Hi,

I've bought this orchid last week and i've noticed black spots at the back of one of the leaves. I am totally new to Orchids and I have no idea what it is.

This leaf has also become yellowish within a day. I've placed this orchid by a window facing west-north so the sun only comes out late on it. it is 4pm now and the window is still in the shade. And also the weather isn't that good in England.
ive only watered it once since I've got it. the side with the spots is the one facing the window.
Any kind of help would be much appreciated as i'm not sure what is the problem.
Also I've noticed that quite a few roots are coming out. does it need repotting?

Many thanks,

Stéfka

[tizzycat]

I don't have any dens Stefka, apart from that one leaf the plant looks really healthy, I'm sure someone will be along shortly to give you the right advice.

Welcome to the forum.

[Stefka]

Originally Posted by tizzycat

I don't have any dens Stefka, apart from that one leaf the plant looks really healthy, I'm sure someone will be along shortly to give you the right advice.

Welcome to the forum.

Thanks a lot... the rest of the plant looks healthy indeed so im just hoping that the problem won't propagate to the other leaves. It's my 1st orchid so i really don't want to kill it.

[brookn]

I could be wrong, but that looks like mites. I would give it a spray with some neem, another in one week, another in two weeks, and once a month after until you are sure you have taken care of the little buggers.

Also, I would not repot as they love to be potbound. You might try some artificial lighting, they really do like quite a bit of light. Mine are outside, and get just a bit less light than my cattleyas.

[Tobi]

Srefka,
I believe you have a Phalaenopsis type Dendrobium. Alot of mine are losing
their leaves from the older canes right now. This is quite normal. At times
they will have these speckled black spot or patches of black before they turn
yellow and fall off. If there were mites you would see them moving with a
magnifying glass on the underside of the leaves along very fine webs. As
long as the new growth leaves are not experiencing this, I would not worry.
They also need alot of light, so I would move them to a south to southwest
window. Sheltered light in a southern window.

[jbigio]

Dendrobium often loss the lower older leaves which as Tobi said often get the spotting you are seeing. The rest of the plant as far as I can see looks good. Its true that Dendrobium don’t like being repotted often but when it’s needed I try not to disturbed the roots as much as possible and they seem to do ok.

[Stefka]

Thanks a lot for your suggestions. I don't see anything moving to the naked eyes, i need to buy a magnifying glass and check more carefully.
I've wiped the leaf with a white tissue and nothing came off and it's not sticky either. and no dusty stuff either.
Do you think i should wash the leaves with soapy water to prevent?
my question might be stupid but which one are the older canes? are they the smaller ones?

[Tobi]

Originally Posted by Stefka

Do you think i should wash the leaves with soapy water to prevent?
my question might be stupid but which one are the older canes? are they the smaller ones?

If there is no visible sign of insect infestations, you don't need to wash the
leaves. It won't hurt to if you are concerned.
The older canes are the ones where the previous spikes and blooms can from.
They can be smaller as the new canes are usually taller once they mature.

[Stefka]

Originally Posted by Tobi

If there is no visible sign of insect infestations, you don't need to wash the
leaves. It won't hurt to if you are concerned.

i think i'll do it anyway as i'm not sure if there are any insect or not on it.

Originally Posted by Tobi

The older canes are the ones where the previous spikes and blooms can from.
They can be smaller as the new canes are usually taller once they mature.

the cane with the problem is not the one where the last blooms were: that's the bigger one. On the pictures the yellow leaf is on the smallest cane. and it is also not the lowest leaf, it is actually the 2nd one from the bottom. i really hope that it is just an old leaf. today the leave is even more yellow (if you compare with yesterday's photos)

[brookn]

Hi it looks like you may have some pitting in the leaves next to it, but I can't tell for sure. If it is, my guess is still bugs. Washing the leaves might do the trick, but I would use the neem spray. The only reason I still think it's bugs is that mine was doing the same thing, and lost two leaves before I sprayed. I try to keep it sprayed once a month as it is outside, and it is putting out all kinds of new growth now.

[Stefka]

OK I've washed the leaves of my Den yesterday. I didn't find ant bugs or anything on it.

Anybody knows if neem spray is available in the UK?

i've looked at what i've have at home and i found something called "Provado Bug Killer". on orchid.org.uk they recommend it to kill lots of different bugs but if its mites it won't treat them. they recommend Bio Liquid Derris Plus or Bug Free. have you heard of them?

What shall I do? you are right Brookn other leaves starts yellowing. This morning i've noticed that another leave is loosing its green. On another cane this time and it is the lowest one. it's not the whole leaf but it comes off in small yellow spots like it's been beaten.

[brookn]

Stefka,
I use Garden Safe that I get from Wal Mart here in the States for approx $5. I know that Cynthia has reccomended this. It says Fungicide 3-in-1 on the bottle, but Cynthia has pointed out is not a fungicide, but great for getting rid of bugs esp. mites. When this happened to my plant I was afraid that it was going to croak on me. The closer I looked the plant over the more I saw small signs of damage. This happend after I had put it outside, and I think the mites could have come from the tree that it is under (covered in ivy). Anyway, I keep it sprayed, i let off for a while, and big mistake. It looks like it might be sending out 3 spikes right now yay! Time will tell, I am excited.

Here is a link to the Garden Safe so you know what to look for. I am not sure you can get it in the UK. I bought it right before Cynthia's post about it, just looked at labels and was pleasantly surprised it had neem (I end up having to order everything cause I live in the middle of nowhere)


http://www.gardensafe.com/

[Stefka]

Originally Posted by brookn

Stefka,
Here is a link to the Garden Safe so you know what to look for. I am not sure you can get it in the UK. I bought it right before Cynthia's post about it, just looked at labels and was pleasantly surprised it had neem (I end up having to order everything cause I live in the middle of nowhere)


http://www.gardensafe.com/

THanks for that, i will try to find it. I went to homebase (DIY shop) and couldn't find anything with neem in it. I've got other leaves turning yellow now and i'll need to act fast. I will have a look at the DIY shop round the corner tomorrow to check if they have any garden safe but my guess is that it's only sold in the USA. If i can't find it i will order it. hopefully i will find an online shop to get it.
and by the way congrats for the 3 spikes

[brookn]

Thanks for the congrats, I am pretty new to owning dends, and this is a victory for me. When I got my first one, I was in a panic, then it aborted the spike it had when it was shipped, more panic hee hee. They are very lovely, and I will keep everyone updated on the spike for sure (I thought they were leaves at first, and still could be for all I know lol) I am keeping my fingers crossed. Good luck, something like this can be discouraging, but once you get it taken care of it feels like a huge accomplishment.

[Stefka]

Yes please post some pics of it...

as i said before it is my first orchid and i bought by chance. I went to the shop to get new pots for my other plants and really liked this den.
Unfortunately she has got little hosts in it
But I'm stubborn and i don't want to bring it back to the shop...
In case i don't find any neem based product, can i use any other bug and mite killer?
I've got another one called "Bug clear gun" which also treat mites but i am scared of using it as it may be too strong.
That what it says on it:

"Broad spectrum, multi purpose insecticide.
No mixing, easy to use.
Controls many common garden pests including greenfly, blackfly, whitefly, caterpillars, cabbage aphids and red spider mites.
All listed fruit and vegetables may be sprayed and eaten on the same day.
Suitable for use on flowers, listed fruits and vegetables.

Contains bifenthrin"

[brookn]

I am not sure about the bug clear gun, maybe pm Cynthia, she will know for sure, and she is very good to answer questions. You can use Bayer Rose and flower in the meantime if it is available there, it will kill the live ones but not the eggs, may halt some of the damage, it has imadocloprid (I may have spelled wrong, but it is close). I will try to get some pics this week, I am currently playing hooky from my homework, and i have school, work, my son's football, and daughter's play, girlscouts etc...I am on overload lol.

[Stefka]

oh now that you mention imadocloprid i've got one spray with Imidacloprid, so i believe it is the same stuff. It's called "Provado bug killer".
you must think i've got a lot of insecticide at home. I live in a rented house and this stuff was left by the previous tenants. I'm spaying the den with it now.
How do you manage between your kids and you study and your work? you must be an organisation master.
I only study and work and I find it hard...

[brookn]

I am always amazed at the amount of poison that is in my house, especially since I try to keep from using it. Since I practically live in the woods, sometimes I just can't help having to use it, and then I feel a bit guilty.

Organization? What's that? Hee hee, mostly I feel like I am flying by the seat of my pants. My daughter, who just turned 11 (I like to refer to her as the mouth) will not let me forget anything. I also am an insomniac, I average about 5 or 6 hours of sleep at best, most nights. Sometimes I answer posts here and I think that my brain must have been fried judging what I said lol. I love this forum though, orchids help center me, and the people here are great.

[Stefka]

Ok Today I bought a magnifying glass to check if there are some tiny things on the plant.
And i've noticed little white things. I'm not sure if they are moving though. I tryied to fix them for about a minute and didn't see them moving. can it be mealy bugs? or are there any white mites?
Yesterday I spayed it with Imidacloprid, that should do the trick for mealy bugs? it seems like this morning the plant was in the same condition as last night i.e. as yellow, no more no less.
11 is quite of a tricky age for girl isn't it? they think they are adults and they obvioulsy aren't. Good luck with everything